Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in cTN Breast Cancer Patients: A Single Center Experience and Review of Current Literature.

PURPOSE

Postmastectomy radiotherapy (PMRT) after neoadjuvant chemotherapy (NAC) in breast cancer patients with initial clinical stage cTN, especially for those who achieved ypTN, is still controversial. This study was to evaluate the survival prognosis of cTN patients after NAC with or without PMRT, and to discuss the selection of patients who may omit PMRT.

PATIENTS AND METHODS

From January 2005 to December 2017, 3055 female breast cancer patients underwent mastectomy in our medical center, among whom 215 patients of cTN stage, receiving NAC with or without PMRT were finally analyzed. The median follow-up duration was 72.6 months. The primary endpoint was disease-free survival (DFS), and secondary endpoint was overall survival (OS). Comparison was conducted between PMRT and non-PMRT subgroups.

RESULTS

Of the 215 eligible patients, 35.8% (77/215) cTN patients achieved ypTN after NAC while 64.2% (138/215) of the patients remained nodal positive (ypTN). The 5-year DFS of ypTN non-PMRT was 79.5% (95% confidence interval [CI] 63.4-95.6%). No statistically significant difference was observed between the ypTN PMRT and non-PMRT subgroups for the 5-year DFS (78.5% vs 79.5%, = 0.673) and OS (88.8% vs 90.8%, = 0.721). The 5-years DFS didn't obviously differ between the ypTN non-PMRT subgroup and cTN subgroup (79.5% vs 93.3%, = 0.070). By using Cox regression model in multivariate analyses of prognosis in ypTN PMRT subgroup, HER2 overexpression and triple-negative breast cancer were significantly poor predictors of DFS and OS, while ypN stage was significant independent predictors of OS.

CONCLUSION

An effective response to NAC (ypTN) indicates a sufficiently favorable prognosis, and PMRT might be omitted for cTN breast cancer patients with ypTN after NAC.