Background and Aims Breast conserving surgery has become one of the standard surgical methods for breast cancer. Breast conserving surgery can preserve the mammary contour of patients and greatly improve the postoperative psychological state and quality of life. BRCA1/2 gene is a susceptibility gene closely related to breast cancer. The impact of BRCA1/2 gene mutation on local recurrence of breast cancer patients after breast conserving surgery is still controversial. This study was conducted to investigate the association of BRCA1/2 mutation with local recurrence of breast cancer patients undergoing breast conserving surgery, and construct a related prognostic model to predict the local recurrence free survival (LRFS) rate of breast cancer patients following breast conserving surgery, so as to provide guidance on indications for breast cancer patients to receive breast conserving surgery.Methods The clinical data of 189 breast cancer patients undergoing breast conserving surgery in Fourth Military Medical University Affiliated Xijing Hospital from June 2014 to June 2016 were retrospectively analyzed. The differences in BRCA1/2 mutation among patients with different clinicopathologic features were compared. The effects of BRCA1/2 mutation and other clinicopathologic factors on local recurrence were analyzed by univariate and multivariate Cox proportional regression models, and a nomogram was constructed to predict the LRFS rate. The model was internally verified by concordance index (C-index), receiver operating characteristic (ROC) curve, and area under curve (AUC). The accuracy of the model was assessed by calibration curves and the clinical benefits and application value of the model were evaluated by clinical decision curve analysis (DCA).Results There were significant differences in age and molecular subtype between the patients with and without BRCA1/2 gene mutation (both P<0.05). The results of univariate Cox equal proportional regression model showed that BRCA1/2 mutation, tumor grade, tumor size, N stage and molecular subtype were relevant risk factors for LRFS of breast patients receiving breast conserving surgery (all P<0.1). The results of multivariate Cox equal proportional regression model showed that BRCA1/2 mutation, tumor size, N stage and molecular subtype were independent risk factors for LRFS of breast patients after breast conserving surgery (all P<0.05). Based on the above variables, the nomogram models were constructed. The C-index of the model was 0.86, and the C-index for internal validation was 0.81. The ROC curve analysis results showed that the AUC of 3- and 5-year LRFS of the model were 0.89 and 0.85, respectively. The calibration curve analysis showed that predicted LRFS of the model had a good consistency with the actual observed values. The DCA showed that the model had high clinical benefit and application value.Conclusion BRCA1/2 mutation is associated with local recurrence in breast cancer patients undergoing breast conserving surgery. The nomogram model based on BRCA1/2 gene mutation can accurately predict the LRFS rate of breast cancer patients after breast conserving surgery, and provide an effective scientific basis for the selection of surgical methods for breast cancer patients.