Discordance of Estrogen & Progesterone Receptors After Neoadjuvant Chemotherapy in Breast Cancer- an Indian Study.

Neoadjuvant chemotherapy forms the initial modality of treatment for primarily inoperable locally advanced breast cancer (LABC). Breast cancer is characterized by cellular heterogeneity. A change in hormone receptor status after neoadjuvant chemotherapy (NACT) has important therapeutic and prognostic consequences. Data on the influence of neoadjuvant chemotherapy on estrogen receptors (ER) and progesterone receptors (PR) are limited. The primary objective of this study is to compare hormone receptor (HR) status before and after neoadjuvant chemotherapy (discordance) in Indian patients. The secondary objective is to study correlation between tumor response and hormone receptor expression. This is a descriptive study of 78 LABC patients who received neoadjuvant chemotherapy from October 2012 to October 2014. All patients who underwent core biopsy and ER/PR assessment before and after NACT were included in the study. Data was collected prospectively from each patient in a structured proforma. Patients were classified as Group A (ER+, PR+), Group B (ER+, PR-), Group C (ER-, PR+), Group D (ER-, PR-). The HR discordance rate & response to neoadjuvant chemotherapy was assessed. Total HR discordance rate was 21.7 %. The ER discordance was 8.7 % and PR discordance was 13 %. PR positive to PR negative discordance was the predominant one. The pathological complete remission (pCR) rate of endocrine responsive patients was 10.2 % and in the endocrine unresponsive group it was 13.8 %. ER/PR status can change after chemotherapy, hence they need to be re-evaluated after neoadjuvant chemotherapy. This becomes therapeutically important when receptor negative becomes positive.