Objective: To investigate whether apoptosis could be induced by preoperative chemotherapy in breast cancer patients, and determine if it is correlated with clinical response and patients' survival.
Methods: Apoptosis was assayed by in situ DNA end labeling and receptors for estrogen and progesterone were examined immunohistochemically. Comparison of the differences in apoptotic index (AI) and clinical response was made between patients received preoperative chemotherapy and those did not, using the one tailed Student's t-test. The Kaplan-Meier method was utilized to calculate relapse-free and overall survival time. Cox proportional hazards model was used to conduct multivariate analysis of prognostic factors and differences in overall survival and relapse-free survival after adjustment for other variables.
Results: Apoptosis was induced by preoperative chemotherapy, especially in lymph node positive patients. Post-chemotherapy AI correlated with better clinical response and increased patient survival, including relapse (disease) free survival and overall survival.
Conclusion: The extent of apoptosis induced by preoperative chemotherapy of primary breast cancer may possibly predict an individual patient's overall response to treatment.