Breast cancer remains the most common malignancy in women, and breast-conserving surgery (BCS) with adjuvant radiotherapy is a standard treatment for early-stage disease. This study assessed the impact of positive surgical margins and secondary surgeries on local recurrence rates and patient outcomes. In this retrospective tumor registry-based study, 24,450 women were eligible for analysis. Of them, 18,082 underwent primary BCS only, 4836 underwent re-excision by BCS, and 1532 underwent re-excision by mastectomy following primary BCS. Our findings indicate that even though re-excision procedures were associated with higher local recurrence rates (HR 1.19
95% CI 1.08-1.33), they did not significantly affect long-term survival (HR 0.98
95% CI 0.87-1.10). This underscores the need for meticulous surgical practices to achieve clean margins initially, and suggests that the choice of surgical intervention should consider individual tumor characteristics and patient preferences to optimize oncological and aesthetic outcomes.