Impact of Neoadjuvant Chemotherapy on Breast Cancer Biomarkers: A Guide for Further Adjuvant Treatment

Introduction and objective: There is discrepancy in practice worldwide whether testing molecular profile on residual carcinoma is warranted and if treatment options should be modified according to final molecular profile of tumor. Therefore, the current study was conducted to evaluate potential changes in breast biomarkers; estrogen receptor, progesterone receptor, HER-2 and Ki67 expression before and after neoadjuvant chemotherapy in Egyptian patients with breast cancer. Patients and method: a hundred locally advanced (initial clinical stage IIB-IIIC) breast carcinoma patients were treated by one of two protocols of neoadjuvant chemotherapy. First protocol: 4 cycles of AC (adriamycin, cyclophosamide) repeated every 21 days, followed by 12 weeks of paclitaxel. Second protocol: FAC (fluorouracil, adriamycin, cyclophosamide) or FEC (fluorouracil, epirubicin, cyclophosamide) for 6 cycles to be repeated every 21 days. Immunohistochemisty of breast biomarkers were performed on both initial biopsies and also surgical resection specimens for each patient. Result: There was statistically significant change of ER (p=0.03). Fifty five tumors were initially negative and thirty nine became negative after neoadjuvant chemotherapy. The rate of conversion from negative to positive was 14%. Forty seven of tumors were initially negative progesterone receptors (PR) and sixty two became negative after neoadjuvant chemotherapy. PR status showed statistically significant change between before and after neoadjuvant chemotherapy (p=0.04). The rate of conversion of PR from positive to negative was 15%. There is no statistically significant change of HER-2 before and after neoadjuvant chemotherapy (p=0.98). There is statistically significant change from high to low Ki 67 index (p=0.006). Rate of conversion changes of Ki 67 from high to low was 20%. Conclusion: neoadjuvant chemotherapy change receptor status and reduce K i67 expression. This change in hormone receptor status from negative to positive offers new endocrine therapy to this group of patients. Accordingly, reevaluation of hormone receptors after neoadjuvant chemotherapy is required to guide further adjuvant treatment