Is mastectomy with immediate reconstruction safe for patients undergoing neoadjuvant chemotherapy? A nationwide study from Korean Breast Cancer Society

Purpose In this study, we compared the prognoses of patients who underwent mastectomy with immediate breast reconstruction (IBR) after neoadjuvant chemotherapy with those who underwent mastectomy. Methods This retrospective study included 87,995 patients who were surgically treated for primary breast cancer between 2008 and 2014. We compared the three groups of patients who were divided based on the following surgeries: breast-conserving surgery (BCS), mastectomy, and mastectomy with IBR. Results Of the 3295 patients who were treated with neoadjuvant chemotherapy, 482 patients achieved a pathological complete response (pCR) and 2813 patients did not (non-pCR). In survival analysis of the pCR patients, the 5-year Overall Survival (5 yr OS) between those who underwent mastectomy with IBR and mastectomy ( P = 0.639) In the non-pCR group, 5 yr OS of the mastectomy with IBR group was 90.0%, while those of the mastectomy group was 84.4% in patients with clinical stage II ( P = 0.032). In a multivariate analysis by Cox regression method revealed that the prognoses of the patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy group in both groups (the pCR group and the non-pCR group). Conclusion In the pCR group, the prognoses of patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy. In the non-pCR group, women in the mastectomy with IBR group had shown worse prognoses than the mastectomy group in advanced clinical stage. Appropriate operation should be determined depending on the status of individualized patients.