Canine mammary tumor: from early diagnosis to postoperative care. Causes of breast cancer in dogs and how to treat it

Diseases with oncological etiology are increasingly common in veterinary practice. No need to talk about how dangerous they are for four-legged pets. One of the most common types of cancer is a tumor of the mammary gland in a dog. Experts diagnose a tumor in females in 55% of cases, and in males in one case out of a hundred. The article will consider in detail the types, causes and symptoms of this neoplasm, as well as methods for its treatment and prevention.

Breast tumor is the most "popular" type of cancer in females. It is very rare in males, but it occurs, because they also have milky organs, though in a rudimentary state. It is important for the owner to understand that cancerous growths are of two types: malignant and benign. Let's discuss them in more detail.

A malignant tumor is almost a death verdict for a shaggy pet. It is constantly growing, extremely aggressive and metastasizes. If it is not treated, then death occurs very quickly, if treated, then the chances of a full recovery still remain negligible. The course of the disease is uncontrolled, and the prognosis is rarely comforting.

Benign neoplasms grow much more slowly and do not affect the tissues of the animal deeply. They do not metastasize, meaning the cancer does not spread throughout the dog's body. The specialist can predict the course of the pathology. If such a tumor is removed, then the chance of its recurrence is extremely small. Sometimes they themselves stop growing, and if they do not interfere with the animal in any way, then they can not be removed at all.

Varieties of the disease

Owners should be clear that mammary tumors in dogs are not always a death sentence. Experienced veterinarians are convinced that cancer occurs only in 40% of cases. Now we will understand what types of oncology of the mammary glands are.

Benign neoplasms include:

• adenomas: simple and complex;
• papillomas formed on the milk ducts;
• fibroadenomas;
• neoplasms of a mixed type, which consist of glandular and connective tissues.

Malignant tumors are presented as:

• carcinoma;
• fibrosarcoma and osteosarcoma;
• tubular cancer;
• nipple adenocarcinoma;
• anaplastic cancer.

Thus, the treatment of a breast tumor depends entirely on the course of the pathology itself in a dog in the body. If we talk about the differences in treatment depending on the tissue type of the tumor, then within the same course, the methods of therapeutic action are always similar to each other.

Causes

Until now, no scientist can give an exact answer to the question of why breast cancer occurs in dogs. However, there are certain factors that significantly increase the risk of such a formidable pathology. These should include:

Symptoms of the disease

In the early stages, a breast tumor is almost impossible to identify. It can manifest itself in the form of a seal or a small pea, which is sometimes very difficult to notice. The animal does not react in any way to the developing pathology, it does not itch, does not whine, does not try to lick it. Obvious symptoms at the very beginning are given only by such an aggressive tumor as inflammatory carcinoma, which affects the mammary glands of a dog with extensive and painful abscesses.

Neoplasms on the glands are most often discovered by the owners by chance, while touching the organ. At that time, a lumpy, stable formation will already be formed there. However, veterinarians are advised to pay attention to such symptoms characteristic of a tumor:

1. Solitary or multiple, with good differentiation, lumps, swellings or nodules that are located in the tissues of the glands of the animal.
2. Often neoplasms are connected to the nipple, may be covered with sores.
3. Lumps and nodules can move freely under the skin of the animal, which is a good sign of their good quality. Or vice versa, they are well fixed and sit deep, which indicates a formidable sign of malignancy.
4. When you press your finger into the area of ​​​​the mammary glands, the dog may whine or even try to bite the owner. This indicates that the tumor is painful.
5. Unpleasant whitish discharge from the nipples.
6. Enlarged lymph nodes in the armpit or groin. This is a terrible sign that the tumor has begun to metastasize.

It is extremely important for the owner to understand that in many respects the development of symptoms in the case of a malignant tumor is related to where exactly it will metastasize. For example, the presence of shortness of breath or difficulty breathing is a sign that metastases are going to the lungs, lameness is in the bones of the paws. If the dog has any of these symptoms, it should be urgently taken to a doctor who will diagnose and determine how to treat the pet.

Diagnostics

Without a full range of diagnostic procedures, it will not be possible to cure the animal. Ordinary palpation, even if the doctor is very experienced, will never be enough to accurately determine the nature of the pathology. Therefore, with a tumor, a biopsy is required - tissue sampling from the affected tissue and its thorough histological examination.

X-rays and ultrasound are used to determine if the tumor is metastasizing. For example, if the animal began to limp, then an x-ray of the paw is prescribed for him, which will help determine whether the bone tissue is affected by cancer cells. The most optimal option is a comprehensive diagnosis, only with its help it is possible to establish at what stage the cancer is and what to do in order to stop its spread.

Methods of treatment

In many respects, the treatment of the animal following the diagnosis depends on the type of oncological disease. So, if the tumor is benign, then it is enough for the doctor to give the pet anesthesia, and then simply remove it. Such operations have a high chance of a successful outcome, and the risk of recurrence of the disease is zero. Another thing is a tumor with a malignant course. They may be inoperable or their metastases have spread too widely, in which case it is not about a cure, but simply about maintaining the pet's quality of life until death.

The owner should be aware that no matter what type of cancer their pet has, removing the tumor will still involve about 2.5 cm of healthy tissue. And around the entire area of ​​neoplasm. Surgical interventions are usually differentiated by size, location and number of tumors. Let's consider them in more detail:

1. Lumpectomy - removal of only a neoplasm with a rim of healthy tissue. After such an operation, the dog can still bear puppies.
2. Simple and regional mastectomy - removal of most of the affected breast.
3. Unilateral and bilateral mastectomy - complete removal of the mammary glands.

If the doctor has determined that the pathology has reached the 3-4 stage of development, then the dog is prescribed chemotherapy. With its help, you can somewhat slow down the growth and development of cancer cells. Unfortunately, the disease in the last stage, in the presence of the formation of distant metastases, is incurable. It remains only to improve the quality of life of the dog and eliminate the most unpleasant signs of the disease. For these purposes, antibacterial agents and painkillers are used. In addition, veterinarians recommend that owners be gentler with their pet, caress it more often, feed it tasty treats and walk in nature. Don't blame the animal for dying.

Disease prevention

There are no special preventive recommendations that allow you to completely avoid the disease. The best solution would be to sterilize the female before the first estrus, this will increase her resistance to this disease. In addition, you need to monitor the diet and hygiene of the dog, do vaccination and deworming on time. Feel the pet's mammary glands more often for the appearance of tumors. Early diagnosis is a disease half cured.

breast tumor- this is an excessive and uncontrolled proliferation of tissues (cells) of the mammary gland. In dogs, there are: adenomas, fibroadenomas, ductal papillomas and mixed tumors (). Synonyms: neoplasm or neoplasia of the breast.

Mammary cancer- a malignant tumor from the epithelial tissue of the mammary gland (). Breast cancers described in dogs: non-infiltrating carcinomas (in situ), simple, complex and special types of carcinomas, sarcomas, carcinosarcomas, and others. Synonyms: Low/medium/well-differentiated breast adenocarcinoma, tubular breast cancer, papillary breast cancer.

Abbreviations: OMZH - tumor of the mammary gland; BC - breast cancer; Ultrasound - ultrasound examination; CT - computed tomography; MRI - magnetic resonance imaging.

Photo 1. Appearance of a benign tumor (adenoma) of the mammary gland in a dog.

Photo 2. Appearance of a malignant tumor (adenocarcinoma) of the mammary gland in a dog.

Etiology and pathogenesis | The reasons

Theory of tumor progression

Thanks to scientific research, it has been proven that mammary tumors in dogs develop gradually, in several stages - from precancerous lesions to invasive carcinomas. The stages are usually divided into adenosis, sclerosing adenosis, intraductal papillomas, sclerosing papillomas, ductal hyperplasia, and ductal carcinoma in situ.

The influence of sex hormones

The development and progression of breast tumors is influenced by female sex hormones - estrogen and progesterone. For example, castration before 1-2 years of age / the first three estrus - significantly reduces the risk of developing benign and malignant tumors of the mammary glands in the future. The increased risk is associated with an increase in the number of sexual cycles that have passed in the animal. Males initially have low levels of estrogen / progesterone in the blood and, as a result, a low risk of developing breast cancer compared to females (does not exceed 1%).

Influence of genes

Violation of some genes (overexpression or mutation) can contribute to the appearance of a tumor of the mammary glands. For example, according to the data in 35.4% of cases, a breast cancer tumor has an increased expression of the c-erB-2 / HER2 gene (epidermal growth factor). In another study, a mutation in the p53 gene (tumor suppressor gene / antitumor gene) was noted in 17% of cases of canine breast cancer ().

Influence of proteins and enzymes

Impaired expression of a number of proteins (E-cadherin, connexin, paxilin) ​​and enzymes can contribute to the progression of mammary tumors in dogs. For example, he found an increased expression of the COX-2 enzyme in 24% of cases of benign neoplasms of the mammary glands and 56% of malignant ones.

Establishing diagnosis

To make a diagnosis and determine the stage of the disease, it is necessary integrated and phased approach. Diagnosis starts with history taking(medical history) and clinical examination animal. After that, as a rule, carry out standard visual studies: X-ray of the chest, ultrasound of the abdominal organs. Sometimes there is a need for computed or magnetic resonance imaging. The next step is to laboratory research: general and biochemical blood tests, urine tests and, if necessary, other studies. In order to determine the type of tumor and make a final diagnosis, biopsy neoplasms for distant cytological or histological examination.

Collection of anamnesis | Disease history

Find out first complaints from the owner and the main purposes of his visit(additional consultation, determination of the stage of the disease, diagnosis or treatment of the disease). Next, an anamnesis of life (anamnesis vitae) and illness (anamnesis morbi) of the animal is collected.

At the cathedral anamnesis of life find out general data about the dog: breed, age, gender, vaccination status, known allergies, chronic diseases, surgical interventions performed, medications taken, etc.

For example, most often tumors are found in middle-aged and older dogs that have not given birth, with a peak incidence of 6-10 years (). VMs are rare at a young age, but cystic hyperplasia may occur during this period of life, especially during or after estrus, and with progesterone-based drugs.

Another example, the presence of concomitant chronic diseases can affect the possibility of anesthesia/surgery/chemotherapy in an animal and, accordingly, influence the choice of treatment tactics/prognosis of the disease.

After taking a life history, the veterinarian studying medical history: duration, growth rate, stages of development and number of neoplasms, previous treatment in other institutions, etc.

For example, rapid growth is characteristic of malignant tumors of the mammary glands, and their large number, the need for volumetric surgery.

Clinical examination | Symptoms and signs

The first step is the doctor general examination of the animal(his physical / mental condition), auscultation of the chest organs (assessment of the cardiovascular and respiratory system), palpation of the abdominal organs (assessment of the shape and size of internal organs), examination of the head and mouth area, thermometry and other necessary manipulations.

next step perform a breast/neoplasm examination. During the examination, note the size, number, form of growth and mobility of breast tumors relative to surrounding tissues.

Breast tumors are usually easy to detect by palpation. Most often, the tumor is localized in the most recent packets of the mammary glands. As a rule, a dense node with clear boundaries is determined, mobile relative to the skin and underlying tissues (). The lesion can be both multiple and single (). In some cases, the tumor is ulcerated and intimately soldered to the skin and subcutaneous tissues, which usually indicates a more aggressive course of the disease.

Special attention is paid to regional lymph nodes(axillary and inguinal). An increase in size, immobility / pain on palpation of the lymph nodes indicates their reactive / metastatic lesion. If necessary, to obtain more accurate information, a biopsy of the altered lymph node is performed.

Photo 3. Appearance of a moderately differentiated adenocarcinoma (cancer) of the mammary gland in a dog.

Photo 4. Appearance of tubular breast cancer.

Visual diagnostic methods

Radiography

Dogs with mammary tumors undergo chest x-rayto assess the condition of the heart / large vessels, lungs / trachea, lymph nodes, and bones/cartilage of the chest.

The lungs are the most common site for metastasis of breast cancer (). Less commonly, metastases can be found in the mediastinal lymph nodes, spine, and ribs. The presence of metastases in distant organs indicates systemic spread and stage IV of the disease with a poor prognosis.

Another important reason for x-rays is to rule out comorbidities. For example, older dogs have hidden lung diseases or heart pathologies (), which can greatly affect the prognosis and treatment of breast cancer.

Photo 5. Metastases of breast cancer in the lungs.

Photo 6. Cardiomegaly in a dog with AOM.

In some cases, it makes sense to conduct x-rays of other parts or areas of the animal's body. For example, in a dog with lameness, an x-ray of a limb is taken. Lameness in older animals is most often associated with chronic joint diseases such as arthrosis. However, the animal may lame due to bone metastasis () or paraneoplastic syndrome ().

Photo 7. Metastases of a cancerous tumor in the humerus.

Photo 8. Hypertrophic osteopathy due to neoplasm in the chest.

Ultrasound procedure

Ultrasound procedure carried out to exclude metastatic lesions of organs and tissues of the abdominal cavity. For example, the liver is the second favorite site for localization of hematogenous metastases of breast cancer. Retroperitoneal lymph nodes may be affected by lymphogenous spread of the tumor. Metastases elsewhere are less common.

Another important reason for performing ultrasound, as well as radiography, is the exclusion of concomitant diseases of the abdominal organs, such as chronic renal or hepatic insufficiency.

Other methods (computer and magnetic resonance imaging)

Computed tomography is performed if conventional x-rays cannot exclude the presence of metastases in the lungs or other organs and tissues (). CT allows you to get a more detailed and three-dimensional picture of the body, compared with radiography. Another advantage of tomography is the possibility of conducting a targeted biopsy of a suspicious focus.

In the future, with the development and reduction in the cost of technology, CT will increasingly replace traditional radiography.

To magnetic resonance imaging resort, as a rule, if the presence of metastases or pathologies in the central nervous system is suspected ()

Photo 9. CT scan of a dog with breast cancer metastases in the lungs.

Photo 10. MRI of a dog with breast cancer metastases in the brain.

Laboratory diagnostic methods

Although blood tests are not helpful in diagnosing and determining the type of tumor mammary gland, they are necessary to assess the state of internal organs / systems and exclude concomitant diseases. If there are indications, they additionally carry out: urine tests, coagulation tests, additional biochemical / enzyme immunoassays and other studies.

For example, a urinalysis of an animal will allow a clinician to assess the excretory function of the kidneys in renal failure, which is necessary to know before using many drugs and administering anesthesia.

Biopsy | Cytology and histology

Biopsy necessary to make a definitive diagnosis and determine the stage of the disease().

AT the preoperative period is rarely necessary conduct cytological or histological studies, as they do not affect the extent of surgical intervention. An exception is a biopsy of altered regional lymph nodes or a tumor with its uncharacteristic clinical manifestation. For example, a doctor may perform a biopsy if they suspect another type of growth (sarcoma, round cell tumor) located in the breast area.

Postoperative histology is essential to determine the type and degree of differentiation of the tumor, as well as to assess the boundaries of its resection (the neoplasm was completely removed or not).

It is worth noting that it is necessary to investigate each individual neoplasm with multiple lesions of the mammary glands, since these tumors can be of different types and degrees of differentiation.

Photo 11. Histological specimen of breast adenocarcinoma. Hematoxylin-eosin, x200.

Photo 12. Histological preparation of a benign tumor of the mammary gland of a mixed type. Hematoxylin-eosin, x200.

Classification | stages

Classifications and stages help to choose the most effective treatment for the tumor and determine the prognosis of the disease. They are also used by veterinarians to “communicate” among themselves, compare the results of different treatments and scientific publications.

For example: T2N0M0 is 3-5 cmbreast tumor without metastases in the lymph nodes and distant organs.

For example: T2N0M0 is a breast tumor stage II.

Note: in general, for malignant neoplasms of the mammary glands, a cautious or unfavorable prognosis is characteristic, and for benign and "unclassified" types - favorable.

Note: for a higher histological degree of malignancy, a lower differentiation of tumor cells is characteristic and, as a result, a more aggressive course of the disease.

Treatment tactics and prognosis

At the moment there are various treatments mammary tumors in dogs. Usually, it consists of surgical removal of the tumor and, if necessary, adjuvant chemotherapy. In some cases, they resort to radiation, targeted or hormonal therapy.

When there is no possibility of radical treatment, the animal is given palliative help to improve the quality of life in various ways (palliative surgery, use of pain medications, management of complications, nutritional support).

Forecast

Histological type and tumor differentiation

The degree of histological differentiation of the tumor significantly affects the prognosis of the disease. The higher the degree of malignancy, the higher the risk of developing metastases or cancer recurrence after surgery ().

According to one study (), only 19% of dogs with grade 0 breast cancer (carcinoma in situ) had recurrence or tumor metastases within 2 years after surgery. However, in dogs with I and II degrees of malignancy, relapses or metastases were noted in 60% and 97% of cases, respectively, over the same period of time.

In addition to the degree of differentiation of the tumor, its invasion into the blood/lymphatic vessels/nodes or stroma of the mammary gland is an additional unfavorable factor affecting the prognosis.

Sarcomas usually do not differentiate according to the given degrees, however they are characterized by biologically aggressive behavior and short lifespan ().

Clinical Factors

Tumor size (T)

Data from a number of studies indicate that the prognosis worsens as the tumor grows in size. So, for example, dogs with a tumor size of less than 3-5 cm have a longer life expectancy compared to animals in which the tumor is larger than 3-5 cm ().

In this regard, mammary tumors in dogs are categorized according to their size into T1 - less than 3 cm in diameter, T2 - 3-5 cm and T3 - more than 5 cm ().

Involvement of lymph nodes (N)

One study involving dogs with mammary carcinoma examined the prognosis of regional lymph node status. In 80% of dogs with involvement of the lymph nodes in the tumor process, metastases developed within 6 months after surgery (), compared with animals without involvement of the lymph nodes, in which relapses or metastases were observed in less than 30% within 2 years after surgery ( )().

In clinical practice, the state of the lymph nodes is divided into N0 - no metastases detected, N1 - metastases in the ipsilateral lymph nodes and N2 - metastases in the contralateral lymph nodes.

Clinical stage of the disease

Clinical TNM classification and stage is an important prognostic factor for dogs with breast cancer. For example, the average life expectancy after surgical treatment of dogs with stage IV and V disease is approximately 6 months, compared with the life expectancy of dogs with stage I, II and III, which is 18 months or more ().

Photo 13. Breast tumor less than 3 cm in diameter (T1). Small tumor size is a positive prognostic factor.

Positive Factors

• Small breeds (they are characterized by a greater number of benign tumors);
• The presence (expression) of estrogen and progesterone receptors in the tumor;
• Male gender (males have more benign tumors);
• Clear palpation borders of the tumor and its size is less than 3 cm;
• A high degree of histological differentiation of the tumor and the absence of invasion of the blood/lymphatic vessels;
• No distant metastases.

Negative Factors

• The presence of inflammation and ulceration of the tumor;
• The size of the tumor is more than 3 centimeters;
• Damage to regional lymph nodes;
• Low histological differentiation and invasion into blood/lymphatic vessels;
• The presence of distant metastases;
• Invasive tumor growth.

Non-influencing factors

• Number of involved glands;

The main symptoms of breast cancer are the presence of one or more dense nodes on the surface / in the thickness of the dog's gland (see photos in the article). Tumor size can vary greatly (from 5 mm to 10 cm) and tends to grow over time. On palpation, the neoplasm is usually mobile and painless with more or less smooth edges.

In advanced cases, metastases can occur in distant organs, mainly the lungs and liver, which are manifested by cough, weight loss, lethargy, jaundice and other symptoms.

Rapid growth, the presence of necrotic areas, inflammation, tenderness, and enlarged lymph nodes are poor prognostic factors that indicate an aggressive course of the disease.

Tumor-like formations of the mammary gland (“mastopathy”) can form / pass (“resolve”) depending on the sexual cycle and the hormonal status of the animal. These pathologies usually occur in animals at a young age.

Breast tumors in dogs do not go away with time (“do not resolve”), but rather increase in size and may become malignant (become malignant). Expectant tactics in such situations does not make sense. Breast tumors commonly occur in middle-aged and older dogs.

The main and most effective treatment for breast cancer is a surgical operation - a mastectomy. In some cases, treatment is combined or supplemented with chemotherapy. In addition, it is possible to use targeted, hormonal, radiation and other therapies.

In such situations, the wound treated with antiseptic solutions(0.05% Chlorhexidine solution) to prevent the development of a secondary infection. The use of wound healing ointments is not recommended due to their stimulating effect on tumor cells. In some cases, systemic antimicrobial(antibiotics) and anti-inflammatory(NSAIDs or GCS) drugs. To protect the tumor from self-injury (licking by animals) and contact with the external environment - they put on a dog blanket.

In most cases bleeding from the tumor stops on its own after a few minutes. To help stop bleeding faster gauze or bandage can be applied to the wound for a few minutes. The use of local cauterizing agents (potassium permanganate, peroxide), as a rule, is ineffective. If the bleeding cannot be stopped on its own or it recurs frequently, show the animal to a veterinarian.

The price of surgery in dogs varies greatly and depends on a number of factors: the body weight of the animal, the stage of the disease, the state of health, the equipment of the clinic, the technique of the operation, the consumables used, and others.

For example, the cost of surgery on a healthy dog ​​weighing 3 kg will be very different from surgery on a dog with heart disease and weighing 40 kg.

The easiest way to find out the price of the operation is to call the veterinary institution and check it with the administrator (do not forget to find out the FULL cost of the operation, which includes the operation itself and anesthesia and everything else).

Literature

Science articles

1. Chang SC, Chang CC, Chang TJ, et al: Prognostic factors associated with survival two years after surgery in dogs with malignant mammary tumors: 79 cases (1998-2002), J Am Vet Med Assoc 227:1625–1629, 2005.
2. Dutra AP, Granja NVM, Schmitt FA et al: C-erbB-2 expression and nuclear pleomorphism in canine mammary tumors, Braz J Med Biol Res 37:1673-1681, 2004.
3. Dore M, Lanthier I, Sirois J: Cyclooxygenase-2 expression in canine mammary tumors, Vet Pathol 40:207-212, 2003.
4. Egenvall A, Bonnett BN, Ohagen P et al 2005 Incidence of and survival after mammary tumours in a population of over 80,000 insured female dogs in Sweden from 1995 to 2002. Preventive Veterinary Medicine 69:109–127.
5. Gilbertson SR, Kurzman ID, Zachrau RE et al: Canine mammary epithelial neoplasms: biological implications of morphologic characteristics assessed in 232 dogs, Vet Pathol 20:127-142, 1983.
6. Nyman HT, Kristensen AT, Skovgaard IM, McEvoy FJ. Characterization of normal and abnormal canine superficial lymph nodes using gray-scale B-mode, color flow mapping, power, and spectral Doppler ultrasonography: a multivariate study. Vet Radiol Ultrasound. 2005 Sep-Oct;46(5):404-10. PubMed PMID: 16250399.
7. Hellmen E, Bergstrom R, Holmberg L, et al: Prognostic factors in canine mammary tumors: a multivariate study of 202 consecutive cases, Vet Pathol 30:20–27, 1993.
8. Kurzman ID, Gilbertson SR: Prognostic factors in canine mammary tumors, Semin Vet Med Surg (Small Anim) 1:25–32, 1986.
9. MacEwen EG, Harvey HJ, Patnaik AK, et al: Evaluation of effects of levamisole and surgery on canine mammary cancer, J Biol Response Mod 4:418–426, 1985.
10. Morris JS, Dobson JM, Bostock DE: Use of tamoxifen in the control of canine mammary neoplasia, Vet Rec 133:539–542, 1993.
11. Pérez Alenza MD, Rutteman GR, Peña L et al: Relationship between habitual diet and canine mammary tumors in a case-control study, J Vet Intern Med 12:132-139, 1998.
12. Perez Alenza MD, Pena L, Nieto AI, et al: Clinical and pathological prognostic factors in canine mammary tumors, Ann Ist Super Sanita 33:581–585, 1997.
13. Sonnenschein EG, Glickman LT, Goldschmidt MH et al: Body conformation, diet and risk of breast cancer in pet dogs: a casecontrol study, Am J Epidemiol 133:694-703, 1991.
14. Schneider R, Dorn CR, Taylor DON: Factors influencing canine mammary cancer development and postsurgical survival, J Natl Cancer Inst 43:1249-1261, 1969.
15. Sarli G, Preziosi R, De Tolla L et al: E-cadherin immunoreactivity in canine mammary tumors, J Vet Diagn Invest 16:542-547, 2004.
16. Scibelli A, Angelo D, Pelagalli A et al: Expression levels of the focal adhesion-associated proteins paxillin and p130CAS in canine and feline mammary tumors, Vet Res 34:193-202, 2003.
17. Torres LN, Matera JM, Vasconcellos CH et al: Expression of connexins 26 and 43 in canine hyperplastic and neoplastic mammary glands, Vet Pathol 42:633-641, 2005.
18. Wakui S, Muto T, Yokoo K et al: Prognostic status of p53 gene mutations in canine mammary carcinoma, Anticancer Res 21:611-616, 2001.
19. Yamagami T, Kobayashi T, Takahashi K, et al: Influence of ovariectomy at the time of mastectomy on the prognosis for canine malignant mammary tumours, J Small Anim Pract 37:462–464, 1996.

Books

• Withrow and MacEwen's Small Animal Clinical Oncology, 5e 5th Edition by Stephen J. Withrow DVM DACVS DACVIM (Oncology) (Author),‎ Rodney Page DVM DACVIM (Internal Med/Oncology) (Author),‎ David M. Vail DVM DACVIM (Oncology) (Author, Editor);
• BSAVA Manual of Canine and Feline Oncology 3rd Edition by Jane Dobson (Editor),‎ Duncan Lascelles (Editor);
• Tumors in Domestic Animals 5th Edition by Donald J. Meuten (Editor);
• Cancer Management in Small Animal Practice, 1e 1st Edition by Carolyn J. Henry DVM MS DACVIM (Oncology) (Author),‎ Mary Lynn Higginbotham DVM MS DACVIM (Oncology) (Author).

Cancer cells affect a huge number of people and, unfortunately, animals. A breast tumor develops in a dog, causing suffering to the animal. About 50% of all tumor-like processes are oncological tumors. And breast cancer not only bitches suffer, but also males as it does not seem surprising. After all, the male sex has mammary glands, although they are unable to produce milk, unlike females.

At the slightest suspicion at the beginning of the development of a mammary gland tumor in a dog, immediately take your pet to the Animal Emergency Veterinary Care Center or call the veterinarian at home by calling.

If the destructive process has already gone far, then it would be best to hospitalize your four-legged pet or pet in our hospital. Veterinarians with a solid baggage of experience and knowledge will conduct a thorough diagnosis using modern equipment and begin to treat the correct diagnosis.

OMZh (tumor of the mammary gland in a dog) is a formidable disease that threatens both females and males. But males suffer from a tumor less often. However, in our article you will find many useful and interesting facts.

Description of the disease and genetic predisposition to a mammary tumor in a dog

By itself, a tumor of the mammary gland of dogs is an uncontrolled growth of cells (in our case, cells of the mammary glands of bitches and / or males). At the same time, the cells of the tumor tissue have a completely atypical structure in terms of histology and morphology. Wherein the functioning of atypical cells also develops abnormally.

Despite significant advances in veterinary medicine, The causes of breast cancer development are still not fully understood.. And this means that it is impossible to predict in advance about the possibility of the onset of this insidious disease. Scientists can only state with certainty the fact of the harmful effects of carcinogens, which are abundantly present in cities with a negative level of ecology. Males can also suffer from tumors of the mammary glands, the disease in such cases is much more severe and almost always ends in death.

Most often, tumors of this kind are found in bitches. who are of fertile age and whose ovaries function normally. This allows veterinarians to judge the hormone-dependent factor in the onset of mammary tumors in dogs. That is why veterinarians recommend performing an operation to remove the gonads at the age of up to six months, that is, before the first estrus.

It is impossible to neglect the predisposition of certain breeds of dogs to the beginning of the development of oncology of the mammary glands. So, are more likely to be in the risk group:

• Two types of poodles - dwarf and toy poodle.
• The two types of spaniel are the English and the Springer.
• Setters.
• Representatives of the German Shepherd.
• Yorkshire Terriers.
• Maltese lapdogs.

This does not mean that dogs of other breeds do not suffer from the described disease. But in these breeds, a malignant tumor process of the mammary glands occurs many times more often than in other breeds.

Types of mammary tumors in dogs and the course of the disease

We have already mentioned that a breast tumor in a dog can be of a benign or malignant type. In this case, a benign neoplasm can be:

• fibroadenoma;
• adenoma;
• papilloma.

The most common tumor called a benign mixed breast tumor. By its name, this neoplasm reflects the complex histological structure of the tumor, which includes various types of cells in one tumor. Such a complex structure is formed by connective tissue with glandular.

Malignant tumors include:

• carcinoma;
• tubular adenocarcinoma;
• anaplastic carcinoma;
• solid carcinoma;
• osteosarcoma.

This is just a partial list of possible cancers.

As in other cases, a breast tumor in a dog is divided into benign and malignant neoplasms. It is on the condition of the bitch's immune system at the time of the onset of the disease that the type of tumor will develop will depend. It is noted that most often there is the occurrence of benign neoplasms in the mammary glands in bitches. But a very important role in the beginning of the oncological process is the nutrition of the animal and the conditions of its maintenance. In these cases, cancer of the mammary glands has an inversely proportional development.

But the hormonal factor also plays an important role in the etiology of breast cancer in dogs. Veterinarians claim that AMF affects those dogs that are prone to false pregnancy. In these cases, the body of the bitch experiences severe hormonal disorders, which lead to severe violations of the reproductive cycle and, as a result, the onset of cancerous degeneration of mammary gland cells.

It cannot be said that with the development of the tumor process, each of its stages passes to the next. But development can be interrupted at any time. We will talk about the symptoms that appear with breast cancer in dogs below.

Canine mammary tumor symptoms

In dogs, it is customary to distinguish between such forms of breast cancer, both nodular and diffuse. At the same time, the second type does not have a clear neoplasm limited in shape and, in essence, is a spilled form. In turn, the nodular form can be expressed in a single and multiple tumor.

The most commonly identified signs of tumor development include the presence of a solid formation in the subcutaneous space of the mammary gland in a dog. It can be either one tumor of considerable size, or many small inclusions that resemble peas. Such tumors remain mobile for a long time and retain their small size. And the diffuse form affects the entire breast tissue and does not always have a clear tumor node. The skin of the affected lobe of the bitch's udder becomes tight and inflamed.

Most often, these inclusions cannot be moved under the skin due to their fusion with nearby tissues. Often there is a very rapid increase in size of these tumors, when they become twice as large in a month.

Another symptom of tumor development mammary glands in dogs is the localization of oncology. Most often, they begin to develop in the last two pairs of glands, but these are not the only places that are most often affected by cancer. Unlike the malignant form of tumors, fibromas do not grow as fast and are distinguished by their smooth structure, which is felt by palpation.

For early detection of the onset of the development of a cancerous tumor in a dog, it is imperative to independently check the mammary glands at least once every six months. On palpation, various kinds of seals and nodules in the gland are easily detected. We advise you to pay attention to their elasticity and the state of the surface of the neoplasm.

Non-oncological tumors have a small size, a flat surface. But malignant tumors are distinguished by the following symptoms:

1. Inhomogeneous and bumpy surface.
2. Too rapid tumor growth rate.
3. Immobility of relatively nearby tissues of the gland.
4. Bleeding ulcerations of the skin over the tumors cannot be ruled out.
5. Neoplasm is not limited to clear boundaries.
6. Local signs of inflammation: redness and fever.
7. Bloody and purulent discharge from the nipple of the affected lobe of the gland.
8. The general depressed state of the dog and its noticeable lethargy.

If the symptoms of carcinoma are detected early, the chance of recovery and survival of the dog is greatly increased.

It is possible to determine the type of lesion and make a clinically significant diagnosis only taking into account numerous analyzes and studies. All these studies, as well as veterinary care in severe cases, are provided by veterinarians at the Animal Emergency Veterinary Care Center. In cases of detection of a tumor in a dog, one should not hesitate and should immediately seek help from specialists.

Diagnosis and treatment of breast cancer in dogs

The most informative method of research is a biopsy of tumor tissue, but removal of carcinoma is also used, followed by a histological examination of the tissues that form it. A chest x-ray and a detailed examination of the lymph nodes help confirm or refute the terrible diagnosis.

The most reliable way to diagnose breast cancer is histological examination of the tumor. With this method, several cells are taken in vivo and the type of neoplasm is already determined by their structure.

Carcinoma is characterized by the formation of metastases. With breast carcinoma, an oncological neoplasm affects the regional lymph nodes and lungs of the animal. For example, with the development of a malignant process in the first two pairs of glands, metastasis affects the lymph nodes that are located near the forelimbs. But the defeat of the last two pairs of the gland already gives metastases to the lymph nodes of the hind limbs and pelvis.

Given the wide coverage of organs with metastases of a cancerous tumor, ultrasound of the internal organs (liver, pancreas) and x-rays of the hind limbs are performed to confirm or exclude the presence of metastases in the bone tissue of the dog's limbs. Also carry out differential diagnosis with mastopathy in diffuse form of breast cancer.

Be sure to conduct general laboratory tests of peripheral blood and urine, a biochemical blood test. And only according to the results of all the tests carried out, it is possible to make a clinically justified diagnosis.

Canine mammary tumor surgery

Treatment of a breast tumor in a dog is carried out in a variety of ways available to modern veterinary medicine. Ultimately, the effectiveness of the treatment is always directly dependent on a variety of factors. It:

1. type of neoplasm.
2. What stage is the tumor in at the time of diagnosis?
3. The age of the affected dog.
4. The physiological state of the animal.

Treatment of benign tumors is most effective. The tumor is resected under anesthesia, and the animal becomes practically healthy. But it is much more difficult to treat malignant tumors.

Due to the spread of metastases, not only the affected mammary gland is removed, but also nearby lymph nodes. With significant damage to organs by metastases, mastectomy and chemotherapy may be prescribed. Also, malignant tumors are subjected to local irradiation with ionizing rays.

It is very important for the owner to understand that the last two listed methods of treatment have a very detrimental effect on the condition of the dog, and if the animal's body is weakened, then this can be fatal.

Veterinary surgeons at the Center for Emergency Veterinary Care for Animals perform mastectomy with maximum organ-sparing and minimal damage to surrounding tissues.

Recovering from Canine Breast Tumor Surgery

With successful resection of the mammary gland affected by the tumor, the dog is provided with full postoperative care, infusion of drugs that support homeostasis processes. Nutrition, provision of antibacterial wound treatment significantly improve the prognosis of a dog's recovery after an operation to remove a mammary gland tumor in a dog and significantly prolong the survival period.

Modern veterinary medicine has achieved quite tangible success in the treatment of infectious diseases, giving our pets a healthy and happy life. However, even today there are diseases that the most qualified doctors and expensive medications cannot cope with. This, of course, is about malignant neoplasms, which, according to statistics, affect every second female dog.

Breast tumors (MT) are called the curse of old dogs for a reason. Veterinarians say that this diagnosis is most likely after your beloved pet has passed the 8-10 year mark. It is at this age that hormonal processes go astray, and the vitality of the body drops markedly, allowing the tumor to progress quite quickly.

What can be the impetus?

There are several causes of tumors:

• First of all, these are pathological hormonal processes, the signs of which can be regular, repeating after each estrus.
• The second reason is the lack of regular childbirth in animals whose reproductive system is running. This point should be paid special attention to lovers of the so-called "", who claim that one single birth in life will significantly strengthen and improve the dog.
• Another sign of hormonal failure, which should alert the owner, is irregular estrus in the pet. If such inconsistencies are observed frequently, this is an alarming bell for an attentive and thoughtful owner.
• Metabolic disorders, common in adulthood, can also cause the degeneration of breast tissue.
• A separate item should be taken out the pathology of the thyroid gland - alas, modern urban ecology often causes such changes, which, in turn, also provoke tumors.
• Fans of using hormones to treat pets should be careful. According to doctors, such drugs are unsafe and trigger the growth of atypical cells in the body.

How to discover

Fortunately, it is not difficult to notice a seal in the mammary gland. At the initial stage, they are limited nodules, which can subsequently increase in size. In order to understand how aggressive and dangerous a neoplasm is, a number of factors should be taken into account and evaluated: growth rate, lymph node damage, and the presence of soft tissue ulceration. When assessing, it is best to rely on the opinion of a specialist, therefore, at the first detection of seals in a dog, it is recommended to see a veterinarian.

If the seal has already appeared, an attentive owner may notice that estrus and especially false pregnancies of the bitch provoke the growth of the tumor. With such a diagnosis, it is strongly not recommended to breed a dog - hormonal changes that accompany pregnancy and subsequent lactation can not only provoke an increase in the nodule in size, but also cause tumor degeneration.

According to the medical classification, tumors are divided into 2 types: malignant and benign. In the first case, the growth of compaction occurs quite intensively, and atypical cells spread throughout the body along with the blood and lymph flow. This is how metastases arise, germinating in the lungs and other internal organs.

If the tumor is benign, the spread of the pathogen to other organs is not observed.

However, the good quality of the tumor does not yet give a 100% guarantee of a successful and quick recovery. Alas, such neoplasms can easily be reborn under the influence of external factors or internal changes in the body.

How to treat

It should be said right away that the only effective method of treating AMF is surgery. Any application of cabbage leaves to the hearth, various energy compresses and cleansing of the chakras are good as a method of mental calming of the host, but they have no effect on the development of the tumor.

The first thing to do when you find a seal is to contact a veterinary clinic. It is better if the dog is examined by a veterinary oncologist (there are more and more specialists of this profile in large cities today). But even if you were not lucky enough to live in Moscow or St. Petersburg, an experienced veterinarian of any district clinic will be able to make a diagnosis and prescribe treatment - alas, there are more and more such cases today, which means that doctors have considerable experience in therapy.

First of all, you should find out what the nature of the tumor is and how likely it is to spread metastases throughout the body. The first question is best answered by cytological analysis. Within its framework, material is taken and the cells of the formation are examined under a microscope. Despite the fact that cytology is by far the most informative way to understand the nature of the tumor, it must be treated with caution. The procedure can provoke the growth of compaction and the formation of other nodules.

In order to find out how widely the cancer cells have spread throughout the body, the doctor will recommend an x-ray. Breast tumors most often metastasize to the lungs, so the first thing the doctor will do is to illuminate this organ with X-rays.

If metastases are not found, and the tumor is benign, the owner can take a breath and tune in to further treatment. The best method of therapy, as mentioned above, is surgery, however, here you should also be aware of some contraindications:

• First of all, the operation should be treated with caution if you are the owner or the animal that is observed.
• If, in addition to the main nodule, multiple smaller neoplasms are palpated in the milk ridge, the operation should also be delayed. Surgical intervention and removal of the largest seal can provoke the growth of other nodules.

If the decision to operate is nevertheless made, the dog should be carefully prepared for the intervention. In addition to x-rays and cytology, you will be advised to do a survey ultrasound of the internal organs and separately the heart, as well as donate blood (general analysis and biochemistry).

Together with the milk bag in which the tumor was found, the nearest lymph nodes, as well as the uterus and ovaries, are traditionally removed. Sterilization will reduce hormonal surges and reduce the risk of new seals.

After surgery, a doctor may recommend that pet owners undergo radiotherapy or chemotherapy. Radiotherapy limits the possibility of subsequent relapses of the disease, and the procedure, carried out with the help of chemicals, is applied immediately after the operation and blocks the occurrence and development of metastases.

Treating tumors in dogs with hormones commonly used to treat cancer in humans is not very effective and can sometimes even be dangerous (for example, the drug tamoxifen is unusually toxic to animals).

After the operation, your four-legged friend is waiting for a long time, and you will need maximum care and attention to your pet.

Prevention

The best way to prevent such tumors known today is early. Moreover, among veterinarians there is a strong belief that sterilization before the first estrus reduces the risk of disease by 15%, and before the second estrus - by 25%. If the removal of the ovaries and uterus occurs later, this does not affect the likelihood of the disease.

Another important preventive measure that owners should not forget is regular palpation of the animal's mammary glands. Finding a tumor at an early stage can greatly facilitate the process of subsequent treatment and increase the chances of a full recovery.

The third important tip is regular preventive examinations at the veterinarian, including ultrasound examination and clinical blood and urine tests.

Having found a treacherous nodule in the tissues of the mammary gland in your four-legged friend, do not despair. Timely treatment and further attention to the health of the pet will help you not only prolong his life for many years, but also make his existence bright, rich and full.

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The authors): M.N. Yakunina, PhD, Head of Oncology Department
Organization(s): Clinic of Experimental Therapy N.N. Blokhin RAMS, Veterinary clinic "Biocontrol"
Magazine: №2 - 2011
Mammary tumors (MBTs) are the most common malignancy in small animals (66). In cats, OMJ ranks third in the structure of oncological diseases after lymphomas and skin tumors (38). Only 10-14% of cases in the mammary gland of cats can be found benign processes, while malignant tumors are diagnosed in 86-90% (37,46,52). The disease affects animals aged 10 to 16 years, but there are observations of the disease in animals at a young age (37).
In dogs, AMF is the second most common after skin tumors, with 50% of tumors being malignant (33,51). Females aged 4 to 16 years are more susceptible to the disease, with a peak in the age group of 7 to 10 years (42).
In the development of breast cancer (BC) in dogs, dyshormonal disorders are primarily isolated (57,59). In almost 70% of cases, the development of a tumor is accompanied by the formation of cysts in the ovaries, and up to 50% - by adenoma or hyperplasia of the adrenal cortex. In addition, frequent false pregnancies or inadequate feeding of puppies is associated with the development of breast cancer (9,12). Lack of delivery is also regarded as a risk factor for breast cancer in dogs. For example, one study demonstrated that more than half of animals with breast cancer had no births (30%) or had one birth (25%), and only 13% of affected dogs had 5 or more births (9). It has been proven that the risk of breast cancer in dogs during castration is reduced several times (59,67). The use of progesterone in dogs to prevent pregnancy also increased the risk of benign mammary tumors (57).
Feline breast cancer is not hormonal (57,59), so the timing of castration does not significantly affect the risk of disease (49,54,52,66). Dishormonal disorders of the mammary gland in cats include the formation of fibroadenomatous hyperplasia, which is characteristic of young cats (1-2 years old), which rarely degenerates into a malignant process (35). It has been noted that the use of hormonal castration drugs can lead to the development of cancer in cats (57).
The occurrence of breast cancer is often preceded by dyshormonal processes, such as hyperplasia, proliferative or fibrocystic mastopathy. A study conducted in 1978 showed that canine breast cancer can occur against the background of a simple cyst (5.7%), non-proliferative fibrocystic mastopathy (35%), a proliferative form of fibrocystic mastopathy (30%), complex-type adenoma (8.6%), benign mixed tumor (4.6%), intraductal papilloma (2.5%) and fibrosclerosis (0.3%) cases. However, the process can also develop de novo (1,4).
Unlike dogs, breast cancer occurs de novo in cats in 90% of cases (66). Dishormonal disorders in young cats (aged 1-2 years) include fibroadenomatous hyperplasia, which rarely degenerates into a malignant tumor. The process of breast cancer metastasis in cats develops along the same pathways as in dogs.
The progression of breast cancer includes local spread of the tumor with invasion of the underlying muscles, skin, and the formation of skin metastases (66). In cats, skin ulceration has been observed in 46.6% of cats with tumors >3 cm and is always associated with poor prognosis (25).
Breast cancer metastasizes by lymphogenous and hematogenous routes. Verified metastatic involvement of regional lymph nodes at initial admission is diagnosed in 58% of cats and 46% of dogs (25). Considering the anatomical structure of the animal lymph circulation system, tumors localized in the 1st, 2nd and 3rd pairs of mammary glands metastasize to the axillary and accessory axillary lymph nodes. When the process is localized in the 4th and 5th pairs of mammary glands, metastases affect the inguinal lymph nodes. In rare cases, when the tumor is localized in the 3rd pair of mammary glands, it is possible to diagnose damage to the inguinal lymph nodes (16,58,66).
The hematogenous pathway of metastasis in canine breast cancer is as relevant as the lymphatic one. Lesions can be diagnosed in the lungs, liver, spleen, kidneys, adrenal glands, heart, less often in the bones and brain (7,10,13). Some clinical forms of canine breast cancer can disseminate through the lymphatic vessels of the skin and form multiple skin metastases. Disseminated breast cancer is diagnosed in 25% of cats already at the initial admission. Hematogenous metastases primarily affect the pleura (41) with the development of tumor pleurisy (up to 63.4% of cases), less often the lungs (16.6% of cases), and in 20% of cases, multiple skin metastases are determined on the inner surface of the thigh. Disseminated breast cancer is diagnosed in 16% of animals at the initial admission, of which metastases in the lungs were detected in 64.3% of cases, in the skin - in 21.7%, in the para-aortic lymph nodes and in the bones - in 7% of cases (25).
It is customary to distinguish between 2 main clinical forms of breast cancer in animals: nodular and diffuse. In some cases, one form of cancer may, due to various circumstances, pass into another. The initial lesion of any region of the breast in 50% of cases is accompanied by the appearance of new tumors in the glands remaining after surgical treatment (28,66).
Nodal shape
The most common form in small pets, accounting for approximately 93% in cats and 67% in dogs of all breast cancer cases. Of these, 70% are multinodular and only 30% are cancer forms with single nodes. Clinically, the nodular form is characterized by the presence of one (single) or several (multiple) tumor nodes against the background of unchanged breast tissue.
diffuse form
As a rule, this form of cancer is characterized by macroscopic and microscopic changes in the entire breast tissue due to a diffuse tumor process. This process can be accompanied by both the formation of a tumor node and its absence. Diffuse cancer occurs in about 7% of cats and 33% of dogs and is associated with a poor prognosis. The diffuse form includes infiltrative-edematous, mastitis-like and armored forms of breast cancer.
The infiltrative-edematous form of growth is characterized by an aggressive course with metastasis to the skin and subcutaneous adipose tissue and has an unfavorable prognosis. In dogs, this form accounts for 24% of all diffuse breast cancer, is primary and occurs much less frequently secondary. In cats, the onset of the disease is exclusively secondary and occurs against the background of postoperative recurrence.
The mastitis-like form of growth is characterized by a rapid growth rate. With this form, one can observe a volumetric formation in the mammary gland, which does not have clear contours, is inactive or immobile relative to the underlying tissues. Regional lymph nodes are always enlarged, the defeat of which often has the character of reactive lymphadenitis, verified pathomorphologically. In dogs, it accounts for 74% of all diffuse cases of breast cancer.
The armored form of growth is a rare variety, the main features of which include severe hyperemia and thickening of the skin of the gland, outwardly resembling erysipelas. The disease is acute and is accompanied by an increase in body temperature. The tumor quickly metastasizes to regional lymph nodes and to distant organs. The disease is difficult to treat and always has a poor prognosis. In dogs, this form occurs in 4% of cases of all diffuse breast cancer.
Currently, TNM classification (Owen, 1980) is widely used in veterinary practice for breast cancer staging, which includes an assessment of the state of the primary tumor focus, regional lymph nodes, and lesions of internal organs (56,66). This classification is common for tumors in dogs and cats with the exception of the size of the primary tumor node (T).
The totality of the information obtained as a result of staging makes it possible to accurately determine the clinical stage of the process. The course of breast cancer is characterized by 4 stages of the process. Animal breast cancer staging is presented in Table 1.
The symbol T describes the state of the primary tumor node.
In dogs:
. T1 - localized tumor up to 3 cm in size, mobile relative to the underlying tissues and not soldered to the skin;
T2 - localized tumor with dimensions from 3 to 5 cm, mobile relative to surrounding tissues;
T3 - localized mobile tumor >5 cm in diameter;
T4 - diffuse tumor, inactive relative to the underlying tissues and / or growing into the skin, or inflammatory carcinoma.
For cats:
T1 - tumor, the maximum size of which<1 см;
T2 - tumor size from 1 to 3 cm;
T3 - tumor >3 cm;
T4 - inflammatory carcinoma.
The symbol N describes the state of the regional lymph nodes
N0 - absence of metastases in regional lymph nodes;
N1 - defeat of one regional lymph node;
N2 - defeat of the main and additional lymph nodes or 2 groups of lymph nodes.
The symbol M describes the spread of metastases to distant organs.
M0 - no metastatic lesion;
M1 - metastatic lesion.
Breast Cancer Treatment
Some time ago, in veterinary medicine, it was believed that breast cancer was an exclusively surgical problem. However, with the development of veterinary medicine and the improvement of specific methods of antitumor therapy, the approach to the treatment of this pathology has become complex, including surgical treatment and antitumor chemotherapy. The choice of treatment tactics directly depends on the clinical form of tumor growth, the clinical stage of the disease (IgM) and the morphological characteristics of the tumor (28,31,39,41,43,49,51,53,56,64,65,68):
in primary inoperable breast cancer (locally advanced or diffuse form of growth, recurrence in the postoperative suture), treatment should begin with preoperative (neoadjuvant) chemotherapy. Further treatment of these patients depends on the results of preoperative therapy.
with a nodular form of growth, the first stage of treatment is surgery, followed by staging of the process, taking into account the preliminary clinical diagnosis and the results of a histological examination (in breast cancer stages 1-11, surgery is the main method of treatment; breast cancer III is treated with complex therapy, including surgery and adjuvant chemotherapy)
in stage IV disseminated breast cancer, chemotherapy is the main method of treatment
Surgical treatment
Until now, the surgical method of treatment is the main one in the treatment of breast cancer in animals (62,51,47,29,18). Indications for radical surgical treatment are operable breast cancer of MM stages.
The choice of the volume of surgical treatment is complex and controversial in veterinary practice, however, almost all operations are radical and include the removal of all packages of mammary glands on the affected side in a single block, along with tissue and regional lymph nodes, regardless of tumor size. Depending on the volume of surgical intervention, regional (removal of 1-3 or 4-5 mammary glands, unilateral (removal of 1-5 mammary glands), bilateral (removal of the 1st to 5th mammary glands on both sides) mastectomy is performed.
For cats, unilateral mastectomy is considered the operation of choice. With multiple bilateral lesions, it is recommended to perform a two-stage unilateral mastectomy with sequential removal of all mammary glands on one side first, then after 14–21 days, removal of all mammary glands on the other side and regional lymph node dissection (32). Recommendations for single-stage total mastectomy are found in the literature, but this operation is indicated only in the absence of the possibility of unilateral mastectomy due to high trauma (85,48,49).
In dogs, the scope of surgical treatment includes regional, unilateral and, rarely, bilateral mastectomy (62,67). When tumors are located in the 4th and 5th or 1st, 2nd and 3rd pairs of mammary glands, regional mastectomy can be used with the obligatory removal of regional lymph nodes, and if the ridge of the mammary glands is affected, unilateral mastectomy can be used. With the defeat of the 3rd pair, the choice of operation depends on the volume of the primary tumor: at stage III - unilateral, and at I-M stage - regional mastectomy. With infiltrative-edematous form of breast cancer (inflammatory carcinoma), surgical treatment is not indicated, the treatment should be conservative.
If at I! stages of the process, treatment is the main one and can lead to a complete cure (18), then at stage III it should be used in combination with systemic chemotherapy. It is known that the life expectancy of animals with BC III with one surgical treatment is 4 months for cats and 7 months for dogs (20,23).
Breast Cancer Chemotherapy
Chemotherapy is one of the main methods of treatment for breast cancer patients (15). Modern anticancer drugs make it possible to extend the life of patients after mastectomy by almost 2 times and improve the quality of life of animals with inoperable stages of breast cancer. Breast cancer in animals has shown sensitivity to many anticancer drugs. A certain effectiveness of Doxorubicin, Cyclophosphamide and 5-Fluorouracil is known both in mono mode and in combinations. Recently, a new drug, Docetaxel (Taxotere), has been introduced into veterinary practice for locally advanced and disseminated breast cancer.
Doxorubicin: in mono mode administered systemically in a single dose of 30 mg/m2 in saline at the rate of 25 ml/kg by infusion over 30 minutes.
Taxotere: in mono mode is administered systemically in a single dose of 30 mg/m2 in saline at the rate of 25 ml/kg by infusion over 30 minutes.
Cyclophosphamide: in mono mode, the drug is administered intrapleurally at a dose of 250 mg / m2 in 5 ml of saline to cats and 10-20 ml to dogs.
Scheme Adriamycin (Aoxorubicin) + Taxotere (AT):
Taxotere in a single dose of 20 mg/m2 is administered dropwise over 30 minutes in physiological saline at the rate of 25 ml/kg, then Doxorubicin is administered without an interval at a single dose of 20 mg/m2 in physiological saline dropwise over 30 minutes.
Postoperative chemotherapy
In veterinary practice, Doxorubicin is considered the main drug of adjuvant treatment. The need for postoperative chemotherapy depends on prognostic factors.
Indications for Postoperative Chemotherapy for Breast Cancer in Cats
Tumor size >2.5-3.0 cm
Regional lymph node lesion
Stage III of the tumor process


Indications for postoperative chemotherapy for breast cancer in dogs
Tumor size >5 cm
Damage to the regional lymph node and lymphatic vessels
The presence of the phenomenon of tumor destruction
Low degree of tumor differentiation
Tumor of a simple type
Postoperative chemotherapy should be started no later than 4-14 days (optimum 4-7 days) after surgery, given that a later start of treatment worsens the prognosis and reduces the survival of patients. Doxorubicin is the drug of choice for adjuvant chemotherapy in both dogs and cats.
Doxorubicin is the main drug for chemotherapy. According to many researchers, Doxorubicin makes it possible to increase the life expectancy of animals with stage III breast cancer by almost 2-4 times compared to one surgical treatment. Own studies in 36 cats with stage III breast cancer, staged according to the TNM classification, showed that postoperative chemotherapy with Doxorubicin prolongs the median time to progression to 8.3 months. At the same time, 90% of cats remained without signs of progression during the first 3 months, 33% - within 1 year, and 14.3% - after 3 years after treatment. The median lifespan for cats was 8.7 months, with 68% of the animals surviving 6 months, 42% 1 year, and 13% surviving 3 years after treatment (20).
In dogs, the use of Doxorubicin in stage III breast cancer can prolong the life expectancy of animals by 2-2.5 times compared with one surgical treatment (60). According to some data, the average life expectancy of dogs (AEL) increases to 294 days (60), and in our study, the average life expectancy of dogs increases to 10.4 months, with a median life expectancy of 8.7 months; 67.9% of animals lived for 6 months; 1 year - 41.7% and 3 years - 12.6%. The median time to progression was 8.3 months, with 90.1% of cats relapse-free at 3 months, 33.1% at 1 year, and 14.3% at 3 years (20).
An attempt to increase the lifespan of cats with stage III breast cancer includes the use of Taxotere as the main drug in adjuvant therapy. It was established that Taxotere in mono mode in a single dose of 30 mg/m2 in three courses with an interval of 21 days leads to a median time to progression of 11.3 months. At the same time, 89% of cats had no signs of progression during the first 3 months, 67% within 6 months and 28% during the 1st year. The median lifespan of the animals in the group was 11.7 months, with 89% of the animals surviving 6 months and 43% being alive for 1 year (21).
Preoperative (neoadjuvant) chemotherapy
First of all, neoadjuvant chemotherapy (NACT) is aimed at reducing the volume of the tumor to achieve operability, optimizing the volume of surgery and reducing the risk of recurrence, and secondly, at preventing metastasis (15,19). Indications for this type of treatment include:
locally distributed process
diffuse form of cancer
relapse
There are observations showing that NAC allows in 50% of cases to achieve tumor operability with a decrease of up to 5% of the risk of postoperative recurrence. Preoperative chemotherapy, as a rule, involves 2-3 courses of treatment, depending on the effectiveness.
For neoadjuvant chemotherapy, doxorubicin is traditionally used in mono mode and in combinations. It has been established that during neoadjuvant chemotherapy in primary inoperable and diffuse forms of breast cancer in dogs, Doxorubicin makes it possible to obtain control of tumor growth in 72% and an objective effect in 36% of cases, including complete (9%) and partial (27%) tumor regression. At the same time, operability is achieved only in 45.5% of dogs in the absence of a significant morphological effect and an increase in the life expectancy of animals: life expectancy = 5 months versus 7 months, life expectancy is more than 1 year in 22% of dogs (Yak.).
The use of neoadjuvant chemotherapy with Doxorubicin in cats with locally advanced or recurrent breast cancer made it possible to obtain partial tumor regression in 18.2% of cases with a moderate morphological effect in 55.7% of cases, to achieve operability in 81% of patients. However, these patients had a short life expectancy of only 4 months (26.8% of cats survived 10 months). However, the sufficiently significant control of tumor growth and the ability to achieve operability of a primary inoperable process allows us to recommend this regimen to animals with limited treatment options, if, due to chronic diseases, it is impossible to use more modern treatment regimens (27).
The introduction of Taxotere into neoadjuvant chemotherapy regimens significantly improves treatment outcomes. Thus, in dogs, the combination of Doxorubicin with Taxotere made it possible to obtain EE in 67% of dogs, mainly due to partial regression (58.7%) with an increase in signs of pronounced morphological regression up to 33.8%. Achieved as a result of neoadjuvant chemotherapy with Taxotere, clinically significant regression of the tumor focus and a significant reduction in the zone of invasion in primary inoperable form of breast cancer, allowed all patients to perform surgical treatment, i.e., achieve operability. In addition, it was possible to increase the life expectancy of dogs (LV was 9.8 months with a one-year survival rate of 38.9% and a one-and-a-half-year survival rate of 19.8% of patients) (22). The use of Taxotere in the neoadjuvant chemotherapy regimen in cats also significantly increases the effectiveness of treatment. An objective effect is recorded in 38.5% of cases, with a frequency of pronounced morphological regression in 18%, and operability is achieved in 84% of cases. Cats have a lifespan of 6.9 months, almost 1.7 times that of the surgical group, with 37.5% of cats surviving 1 year and 18.7% surviving more than 18 months (27).
Treatment of disseminated breast cancer
The treatment of disseminated breast cancer is a major challenge for oncologists. Hematogenous multi-organ metastasis is considered the most significant for the deterioration of the quality of life of animals with disseminated breast cancer. With metastatic lesions, the general condition and, accordingly, the quality of life of patients deteriorates, mainly due to the development of respiratory, pulmonary heart failure. It is known that the average life expectancy of animals with stage IV breast cancer is 2 months. The primary therapeutic goal in disseminated breast cancer is to improve the quality of life by relieving the corresponding symptoms and increasing their duration (15).
The systemic nature of tumor lesions requires systemic therapy, therefore, at this stage of the disease, chemotherapy is the main method of treatment. As a rule, antitumor drugs are used that are effective in the main localization of the tumor process: Taxotere and Doxorubicin in mono mode and in combination. It has been shown that chemotherapy with Doxorubicin does not lead to a significant clinical effect in stage IV of the disease (40). The addition of Taxotere to Doxorubicin (TA regimen) makes it possible to obtain CRO in 70% of patients, mainly due to the stabilization of the process. At the same time, the survival rate of dogs increases by almost 2 times, life expectancy = 3.9 months, and 31% of the animals lived for 6 months and 15.6% for more than 1 year. With monochemotherapy with Taxotere of disseminated breast cancer in cats, the life expectancy of animals increases by 3 times and is 6.5 months, KRO in 82.2% of animals, mainly due to stabilization. At the same time, 55.5% lived for 6 months, and 27.7% of patients lived for more than 1 year (26).
The most difficult is the treatment of patients with tumor pleurisy. The severity of the condition is determined by the development, first of all, of respiratory failure, leading to the death of the patient. Clinical symptoms are associated with the development of respiratory failure, which increases in proportion to the decrease in lung capacity:
pleural effusion
abdominal breathing
cyanosis of the mucous membranes
dyspnea
death of pulmonary heart failure due to compression of the lungs and heart by accumulating effusion.
The average life expectancy of patients with tumor pleurisy is 2 weeks and rarely reaches 1 month. Given the specifics of the manifestations of the disease, treatment includes the following measures:
thoracocentesis with pleural effusion evacuation,
intrapleural administration of cytostatics or sclerosing drugs,
symptomatic administration of diuretics,
systemic chemotherapy.
The traditional treatment of OP with intrapleural administration of Cyclophosphamide does not show high efficiency and can be attributed to symptomatic therapy. NRM did not exceed 0.6 months. Treatment of OP with Taxotere alone results in a cessation of pleural effusion accumulation in almost 60% of cats. The increase in the life expectancy of cats with OP increases 5 times (LV = 3.2 months) in comparison with the ineffective intravenous chemotherapy Cyclophosphamide. An interesting fact is that in the case of the use of Taxotere in the neoadjuvant period, its repeated use for OP is effective only in combination with Doxorubicin. ■

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