Factors Associated with Positive Margin Requiring Re-Excision after Oncoplastic Breast-Conserving Surgery.

Multiple factors are associated with re-excision after breast-conserving surgery (BCS), however there is minimal literature discussing factors associated with re-excision after oncoplastic BCS (OBCS). This retrospective study aimed to identify factors associated with positive margins requiring re-excision after OBCS. A retrospective review was performed on patients who underwent OBCS between October 2021 and May 2024. Subjects were divided into those who required re-excision and those who did not. Factors were evaluated including patient age, body mass index, smoking status, presence of hypertension and diabetes mellitus, tumor multifocality, microcalcifications, tumor size, human epidermal growth factor receptor 2+ (HER2+) status, triple negative (estrogen receptor-/progesterone receptor-/HER2-) status, and tumor pathologies including ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and invasive lobular carcinoma. The need for re-excision was significantly associated with a DCIS pathology (50% of patients, P = 0.021), and the lack of need for re-excision was associated with an IDC pathology (12.5% of patients, P = 0.005). There was no significant correlation in the need for margin re-excision based on age, body mass index, smoking status, the presence of hypertension or diabetes mellitus, tumor size, the presence of invasive lobular carcinoma, triple negative status, presence of HER2 or triple negative status, microcalcifications, or tumor multifocality. Most factors associated with re-excision after BCS were not associated with re-excision after OBCS in our study. Similar to data published for BCS, however, our results show that DCIS pathology was significantly associated with re-excision in patients who undergo OBCS. In addition, the presence of IDC seemed to be negatively associated with re-excision after OBCS.