Tumor proliferation of mammary gland in bitches

Thanks to breeders' and veterinary care, dogs' age is increasing, which results in proportional increase in diseases, including cancer. Mammary gland cancer is the most common oncologic problem in bitches. Development of neoplasms is affected by endogenous factors (for example hormones), and exogenous factors also (radiation, carcinogenic substances, etc.). These factors cause mutations, which affects the formation of cancer growth. We divide tumours on true and false ones. False tumours are e.g. cysts. True tumours are either benign or malignant, which create daughter centres called metastasis. Malignant tumours bear worse prognosis than benign tumours. Metastasis and tumours affect inidividual's organism by e.g. negative effect on organ function. Individual can stimulate tumours by e.g. hormone secretion. Tumour classification is important because of determining the right treatment and prognosis for the future. Classification is divided in three parts: typing, grading, staging. Typing divides tumours into groups by their effect on tissues, or by individual tumours. Grading divides tumour by level of their differentiation. Staging classifies tumours by TNM, where T defines tumour's size, N defines level of lymphatics invasion and M defines metastasis formation. Mamary gland function is divided in three physiological phases: mammary gland development, lactation and galactopoesis. Mammary gland is probably modified sweat gland. Lactation is affected by hormone prolactin, which supports mammary gland development. Galactopoesis is state, which maintains lactation. It's important to prevent stress in this phase, because stress hormones block oxytocin, so milk ejection isn't coming about. Effect of hormones also change by estrous cycle phase. In bitch, there are those phases: proestrus, estrus, diestrus and anestrus. Estrous cycle deffects can occur and those deffects can cause so called false pregnancy. This state can result in diseases like pyometra or mastitis. Etiopathogenesis of mammary tumours is affected by two kind of factors, endogenous and exogenous. Prevention is also important, this includes more quality care and feed. Another important prevention can be adequate exercise and potential sterilisation of the female. If the animal is already ill, then there is important to discuss it with veterinarian and start treatment as soon as possible. Firt method of treatment is surgical, which is divided by mammary gland invasion. Other method is chemotherapy, which is becoming more and more frequent as support treatment method after surgery. Third method is called radiological. It's relatively new type of therapy, but it is, unfortunately, still relatively expensive. Last method is called hormonal. Again, it is used usually as support treatment after surgical removal of the tumour. There are used many diagnostic methods for clinical evaluation of mammary gland tumours, e.g. cytology, USG, RTG. Prognosis determination and post-surgical care is also important. Main complication is disease recurrence, which is more frequently occuring in malignant tumours than in benign tumours. Most important is prevention and treatment start as soon as possible after diagnosis assesment. It is appropriate to not to burden breeding bitch with frequent litters, or let veterinarian perform ovariohysterectomy (OHE) on bitch, which is not used for breeding. Ovariohysterectomy reduces probability of development of this disease.It is very important for breeder to regularly check mammary gland by palpation and immediately visit veterinarian with every change or lump