Neoadjuvant Chemotherapy of Breast Cancer: Tumor Markers as Predictors of Pathologic Response,Recurrence, and Survival

Abstract: This study reports the value of the tumor markers estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in predicting the response of breast cancer to neoadjuvant chemotherapy. A community cancer center prospectively maintained breast cancer database containing over 8,000 patient records was used. Since 1989, 464 patients were treated with neoadjuvant chemotherapy followed by surgical resection and were tested for ER and PR. Estrogen receptor and/or PR positive patients were considered hormone receptor (HR) positive. Human epidermal growth factor receptor 2 status was available on 368 patients. Total, breast, and nodal pathologic complete response (pCR) rates, recurrence, and overall survival were assessed. Total and breast pCR rates were higher in HR negative (HR?) patients (26% and 32%, respectively) than in HR positive (HR+) patients (4% and 7%, respectively; p < 0.001). Compared to HR+ patients, HR? patients had higher recurrence rates (38% versus 22%; p < 0.001), a shorter time to recurrence (1.28 versus 2.14 years; p < 0.001), and decreased overall survival (67% versus 81%; p < 0.001). Human epidermal growth factor receptor 2 positive patients treated with neoadjuvant trastuzumab (NAT) demonstrated higher total pCR (34% versus 13%; p = 0.008), breast pCR (37% versus 17%; p = 0.02), and nodal pCR rates (47% versus 23%; p = 0.05) compared to HER2+ patients not treated with NAT. Furthermore, HER2+ patients who received NAT had lower recurrence rates (5% versus 42%; p < 0.001) and increased overall survival (97% versus 68%; p < 0.001). In conclusion, breast cancer HR status is predictive of total and breast pCR rates after neoadjuvant chemotherapy. Although HR? patients derive greater benefit from neoadjuvant chemotherapy in terms of pathologic response, they have worse outcomes in terms of recurrence and survival. Hormone receptor positive patients demonstrate significantly less response to neoadjuvant chemotherapy, but significantly better overall outcome. For both HR? and HR+, addition of NAT for HER2+ tumors results in both a superior response and outcome.