Breast cancer outcomes after skin- and nipple-sparing mastectomy in BRCA pathogenic mutation carriers versus non-BRCA carriers

Our previous study on breast cancer BRCA carriers disclosed a high local recurrence (LR) rate in patients who underwent skin sparing (SSM) or nipple sparing mastectomy (NSM) without postoperative radiation therapy (RT), compared to breast conservation surgery or mastectomy with RT. The current study compares the LR rates in BRCA versus non BRCA carriers after SSM/NSM in relation the receipt of RT. Methods: The study was approved by the institutional ethics committee. Data collected included patient- (e.g., age), tumour- (e.g., subtype, stage), and treatment-related factors and outcomes. LR was defined as ipsilateral chest wall recurrence. P value ≤ 0.05 was considered statistically significant. Results: A total of 255 patients (127 BRCA, 128 non-BRCA) were included. Patients who did not receive RT had an earlier disease stage (most N0). No differences were found for LR rate in non-BRCA versus BRCA groups per involved breast and per patient. Comparing the subgroup of patients who did not receive RT, there were no statistically significant differences in LR between non-BRCA versus BRCA (p-value > 0.05). Similarly, there were no significant differences in LR for the subgroup of patients who did receive RT (p-value > 0.05). Regardless of BRCA status, patients who received RT had significantly lower LR rates. No differences in overall survival were noted between the groups. Conclusions: Our results confirm high LR rates after SSM and NSM in patients who are not treated with RT, independent of BRCA-status. This mandate further investigation, as previous studies did not show a benefit of postmastectomy RT in the early breast cancer stage of those patients.