The aim of the present study was to evaluate the role of different risk and prognostic factors of mammary carcinoma in bitches.
Bitches enrroled in the study were submitted to a two years follow up: relapse, new neoplasia, metastasis and death were taken into consideration. Different aspects were considered.
In our population mammary gland tumors occurred mostly in 9.4 (mean) year old bitches with a higher incidence between 10 and 11 years (range 4 to 15 years). The study showed an increased risk of mammary gland tumors only in Dalmatian and Yorkshire Terrier dogs but not in other breeds, different from other previous studies . A significant reduction in mammary neoplasia incidence was found in Labrador and Golden Retriever bitches. Both obesity and home-made diet may be an important risk factors. No significant correlation between diet tipology, body size and body condition score was found. Suburban environment seemed to play an important role in developing of mammary gland tumors. The topographic distribution of neoplasias was in agreement with previous studies showing a higher incidence of tumors in inguinal mammary glands (more than 60%).
A statistically significant correlation (p<0.05) was found between the reproductive phase cycle at the moment of the diagnosis of mammary tumors their localization.
Moreover bitches in cycling activity (proestrus, estrus and diestrus) showed a higher probability to develop inguinal mammary tumors. While the mammary tumors arosen during the cycling activity had only an inguinal localization, during anaestrus they developed in all mammary glands, showing a major incidence in caudal glands.
No statistically significant correlation was found between the anamnestic report of pseudopregnancy and the percentage of malignancy, pseudopregnancy and multiple tumors, and between pseudopregnancy and neoplastic localization.
Ovariectomy didn’t influence significantly the relapse and the metastasis of mammary carcinoma and the surviving of bitches 6, 12 and 24 months after surgery. On the contrary, ovariectomy showed a significant influence (p<0.05) on the risk of developing new tumors after surgery.
TNM in the first two stages seemed to be inadequate for giving an accurate prognosis and assessing a therapeutic plan.
Histotype, histologic grading and histologic staging seemed to be adequate and accurate prognosis factors.