Breast-conservation Therapy After Neoadjuvant Chemotherapy Does Not Compromise 10-Year Breast Cancer-specific Mortality.

Objectives: Neoadjuvant chemotherapy can increase the rate of breast-conserving surgery by downstaging disease in patients with breast cancer. The aim of this study was to determine whether patients who received neoadjuvant chemotherapy have equal survival after breast-conservation therapy compared with mastectomy.

Material and methods: Using the New Jersey State Cancer Registry (NJSCR) patients with a primary breast cancer diagnosed between 1998 and 2003 who underwent neoadjuvant chemotherapy were selected (n=1,468). Of those, only patients who received lumpectomy plus radiation (n=276) or mastectomy without radiation (n=442) were included in the analysis. The main outcome measured included 10-year breast cancer-specific mortality, with 90% of patients with known vital status through the end of 2011.

Results: Baseline characteristics did not differ significantly between the breast-conservation and mastectomy without radiation groups except with respect to summary stage and lymph node involvement. After propensity score matching these differences were no longer statistically significant; however, both estrogen and progesterone status achieved statistical significance. The Kaplan-Meier survival curve showed that the breast-conservation group had significantly higher breast cancer-specific survival than the mastectomy group (P=0.0046). After adjusting for the propensity score in the regression model, the breast-conservation group continued to show significantly better survival than the mastectomy group (hazard ratios, 0.46; 95% confidence interval, 0.27-0.78).

Conclusions: This study is consistent with previous research showing that breast-conserving surgery after neoadjuvant chemotherapy does not reduce breast cancer-specific survival. In fact, patients undergoing breast-conservation after neoadjuvant therapy appeared to have better survival than patients undergoing mastectomy without radiation.