Assessment of Predictive Markers of Response to Neoadjuvant Chemotherapy in Breast Cancer

OBJECTIVE: To identify the predictive markers associated with chemotherapy sensitivity, especially those producing pathological complete response (pCR) following neoadjuvant chemotherapy (NACT) in patients with locally advanced breast cancer. METHODS: Core needle biopsy of SO locally advanced breast cancer patients was analysed for histopathology, grade, oestrogen receptor, progesterone receptor, HER2, Ki-67, p53, Bcl-2, and BAX before starting NACT. This was correlated with response to NACT using Response Evaluation Criteria in Solid Tumours criteria. RESULTS: The mean tumour reduction rate per chemotherapy cycle was significantly higher in BAX-positive (p = 0.01) and Bcl-2-negative (p = 0.04) tumours. BAX expression significantly (p = 0.043) correlated with a response of an at least 30% reduction in tumour size post-NACT on multivariate analysis. A significant relationship was seen between loss of Bcl-2 expression and pCR on univariate (p = 0.048) analysis. Overall, all of the above 12 parameters had 30.4% and 28.5% success in predicting clinical complete response and pCR, respectively, by the Cox and Snell formula. CONCLUSION: Of all parameters examined, only the apoptosis-related genes (Bcl-2 and BAX) seemed to exert some influence on the response to NACT, and neither by itself was sufficient to predict pCR; however, SO patients is not sufficient to simultaneously analyse several predictive markers. [Asian J Surg 2010;33(4):157-67]