To Study the Histopathological, Hormonal Receptor Changes and Pathological Response Categorization in Breast Carcinoma Following Neoadjuvant Chemotherapy.

Background and Objective: Neoadjuvant chemotherapy (NACT) is currently a standard therapeutic approach to downstage the locally advanced breast cancer. This study aimed to 1) Evaluate the post NACT histopathological changes in the mastectomy specimens and lymph nodes, 2) Compare the immuno-histochemistry profiles of hormone receptor status ER, PR and HER2/NEU before and after NACT, 3) Categorize the patients according to the pathological response. Methods: Hospital based prospective study was conducted on 50 cases, diagnosed as carcinoma breast on trucut biopsies and assessed for ER, PR and HER2/NEU receptor status. Following NACT, modified radical mastectomy specimens were evaluated for histopathological changes, residual tumor and patients were categorized according to pathological response. The specimens with residual tumor were again subjected to ER, PR and HER2/NEU receptor status. Then comparison of ER, PR and HER2/NEU status was done between pre and post NACT specimens which showed residual tumor. Results: Histopathological changes observed were DCIS (14%), inflammation (88%), necrosis (74%), fibrosis (90%), calcification (12%) and LVI (20%). Among 50 cases, 14% showed pathological complete response, 48% showed pathological partial response and 38% showed pathological no response. Among 43 cases, comparison of ER, PR and HER2/NEU status between pre and post NACT cases documented a statistically significant loss of ER expression (p=0.020) and PR expression (p= 0.014) while no significant difference was observed in HER2/NEU expression. Conclusions: This study highlights the NACT induced histopathological, hormonal receptor-ER, PR and HER2/NEU changes along with assessment of pathological response to therapy which provides valuable prognostic information and helps in directing the effective hormonal/targeted treatment. [ABSTRACT FROM AUTHOR]