Oncoplastic Breast-Conserving Surgery for Tumors Larger than 2 Centimeters: Is it Oncologically Safe? A Matched-Cohort Analysis

Background: Oncoplastic surgery is a well-established approach that combines conserving treatment for breast cancer and plastic surgery techniques. Although this approach has been described for T2 tumors, no long-term oncologic follow-up and no comparison with patients undergoing mastectomy has been published. The purpose of the study was to demonstrate that oncoplastic surgery is a safe and reliable treatment for managing invasive primary T2 breast cancer. Methods: We compared a consecutive series of 193 T2 patients who have undergone oncoplastic surgery (study group) with 386 T2 patients who have undergone mastectomy (control group). The endpoints evaluated were disease-free survival (DFS), overall survival (OS), cumulative incidence of local recurrence (CI-L), regional recurrence (CI-R), and distant recurrence (CI-D), all measured from the date of surgery. Results: Median follow-up is 7.4 years. The OS is similar within the two groups: 87.3 and 87.1 % at 10 years in the ONC group and control group, respectively (p value, adjusted for multifocality and tumor size, 0.74). Also, the DFS is similar in both groups: 60.9 and 56.3 % at 10 years in the ONC group and control group, respectively. The incidence of local events is slightly higher in the oncoplastic group, whereas the incidence of regional events is slightly higher in the mastectomy group. These differences are not statistically significant. The cumulative incidence of distant events is similar within the two groups. Conclusions: To our knowledge, the present study provides the best available evidence to suggest that oncoplastic approach is a safe and reliable treatment for managing invasive pT2 breast cancers.