Survival After Breast-Conserving Surgery Compared with that After Mastectomy in Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

Abstract

Background: Breast-conserving surgery (BCS) plus radiotherapy (BCS + RT) has been shown to improve survival compared with mastectomy in patients with early breast cancer; however, whether this superiority is maintained in breast cancer patients receiving neoadjuvant chemotherapy (NCT) is unclear. We evaluated and compared the survival outcomes after BCS + RT and mastectomy in Korean women with breast cancer treated with NCT. Methods: We evaluated 1641 patients who received NCT before surgery (BCS or mastectomy). We performed propensity score matching to minimize potential bias due to factors other than the surgical method and compared the 5-year, disease-free survival (DFS), distant metastasis-free survival (DMFS), and overall survival (OS) rates before and after exact matching. Results: Among the 1641 patients, 839 (51.1%) underwent BCS + RT and 802 (48.9%) underwent mastectomy. Patients who underwent mastectomy had larger tumors and more frequently had positive nodes. For BCS+RT and mastectomy, the unadjusted 5-year DFS, 5-year DMFS, and 5-year OS rates were 87.0% and 73.1%, 89.5% and 77.0%, and 91.8% and 81.0%, respectively (all p < 0.05 = 0.000). After PSM, 5-year DFS, 5-year DMFS, and 5-year OS rates for BCS + RT and mastectomy were 87.6% and 69.1%, 89.7% and 76.0%, and 89.1% and 75.7%, respectively (all p < 0.05). In both unadjusted and adjusted analyses accounting for various confounding factors, BCS + RT was significantly associated with improved DFS (p < 0.05), DMFS (p < 0.05), and OS (p < 0.05) rates compared with mastectomy. Conclusions: BCS + RT does not impair DFS and OS in patients treated with NCT. Tumor biology and treatment response are significant prognostic indicators. Our results suggest that BCS + RT may be preferred in most breast cancer patients when both BCS and mastectomy are suitable. © 2022, Society of Surgical Oncology.