Investi̇gati̇on of effi̇cacy of two di̇fferent chemotherapy protocols used i̇n neoadjuvant chemotherapy i̇n locally advanced stage mammary tumors i̇n dogs

Canine mammary tumors are the most pervasive tumor in female dogs The ruling treatment option in these tumors is surgery. In this study; The intented is demonstration of clinical effectiveness and reliability of two different neoadjuvant chemotherapy protocols occurring of doxorubicin/cyclophosphamide combination and paclitaxel in dogs with locally advanced mammary tumors, determination of subtypes based on Ki67, HER2, estrogen and progesterone biomarkers in biopsy specimens taken before neoadjuvant chemotherapy, to determine the prognostic value of these subtypes in predicting the clinical response to neoadjuvant chemotherapy and to evaluate the immunohistochemically comparative changes of neoadjuvant chemotherapy on these biomarkers in breast tissues taken after the operation. In the study, 30 small dogs which has advanced phase mammary tumor randomly divided into two groups, Neoadjuvant doxorubicin/cyclophosphamide combination was used in one of the groups as doxorubicin 25-30 mg/m2 and cyclophosphamide 100 mg/m2 in the form of i.v. slow injection with an interval of 3 weeks for 4 cures, while the other group was given paclitaxel chemotherapy as 60mg/m2 i.v. slow injection once a week for 12 weeks Changes in Ki67, HER-2, estrogen and progesterone biomarkers were investigated immunohistochemically in tumor tissues taken 4 weeks after the end of chemotherapy. 3/15 (20%) complete response, 10/15 (66.66%) partial response, 1/15 (6.66%) stable response in dogs treated with anthracycline/cyclophosphamide (A/C) chemotherapy disease and progressive disease were determined. 1/15 (86.66%) of the dogs who received paclitaxel chemotherapy gave partial response, while 1/15 (6.66%) complete response and progressive disease were observed. In both groups, the rate of those who responded to treatment was found to be statistically significant compared to the rate of those who did not respond to treatment. Subtypes of KMTs were determined based on Ki67, HER2, estrogen and progesterone biomarkers in biopsy samples taken before neoadjuvant chemotherapy. The excess of luminal type A breast tumor was found as statistically significant. In the anthracycline/cyclophosphamide group, the percentage of complete response in the triple-negative subtype was higher than the others. Changes in biomarkers before and after treatment were not statistically significant. As a result, was decisived that the neoadjuvant use of these chemotherapy protocols is an effective, safe and alternative treatment option to the current treatment approach in the applied dose and range.