Long-term outcomes of skin-sparing mastectomy and nipple-sparing mastectomy versus traditional mastectomy in breast cancer: a case-control study based on preoperative ultrasound and clinical indicators

Background and objective Nipple-sparing mastectomy (NSM) and skin-sparing mastectomy (SSM) are recognized for their aesthetic benefits in breast cancer patients. However, detailed evaluations with large samples of their long-term oncological effectiveness are limited. This study aims to compare the long-term oncologic outcomes of NSM/SSM and traditional mastectomy (TM) in patients with stage I-III breast cancer and to identify influential preoperative factors. Methods Among the 12,802 breast cancer patients who underwent surgery from 2009 to 2022 in West China Hospital of Sichuan University, 295 NSM/SSM patients and 584 TM patients were selected after propensity score matching adjusted for variables. Survival outcomes were analyzed using Kaplan-Meier estimates, Fisher's exact test, and log-rank tests, with Cox regression identifying survival predictors. Results The median follow-up period was 97.93 months. Local recurrence (LR) was 5.76 +/- 1.36% for NSM/SSM compared to 3.25 +/- 0.73% for TM (p = 0.076). Overall survival (OS) was comparable (p = 0.601), while disease-free survival (DFS) showed a trend toward significance (p = 0.066). However, there was a significant difference in distant metastasis-free survival (DMFS) (p = 0.029). The 5-year OS rates between the matched groups were similar (98.11% vs. 98.09%, p = 1.000), while the TM group exhibited higher 5-year DFS(95.14% vs. 92.03%, p = 0.335). Following the univariate analysis, multivariate analysis identified significant DFS predictors: stage (HR = 2.701, p = 0.031), radiotherapy (HR = 1.928, p = 0.018), and targeted therapy (HR = 5.584, p < 0.001). For OS, significant predictors included stage (HR = 8.309, p = 0.021) and PR status (HR = 0.35, p = 0.010). Conclusions NSM/SSM demonstrated comparable OS and DFS to TM, though with lower DMFS. Preoperative ultrasound parameters showed no significant impact on long-term outcomes, confirming the oncologic safety of NSM/SSM. Tailored adjuvant therapies and appropriate follow-up may further optimize patient prognoses.