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.