Clinical and patient-reported outcomes after oncoplastic versus conventional breast conserving surgery—a longitudinal, multicenter cohort study

Abstract Background Oncoplastic breast conserving surgery (OP-BCS) is becoming increasingly popular to avoid mastectomy or optimize cosmetic outcomes of breast conserving surgery (BCS). Few studies have compared clinical outcomes and patient-reported outcomes (PROs) of OP-BCS to conventional BCS (C-BCS). This study aims to compare clinical outcomes and short and long-term PROs after OP-BCS and C-BCS in a large prospective breast cancer cohort. Methods Women in the prospective, multicenter UMBRELLA-breast cancer cohort who underwent OP-BCS or C-BCS were included. Clinical outcomes and PROs (measured by EORTC QLQ-C30/BR23) up to 24 months postoperatively were evaluated. Mixed-model analysis was performed to assess differences in PROs over time between groups. Results 1628 (84.9%) patients received C-BCS and 290 (15.1%) OP-BCS. After C-BCS and OP-BCS, free resection margins were obtained in 84.2% (n = 1370) and 86.2% (n = 250), respectively, reoperation for re-exision of margins <3 months occurred in 5.3% (n = 86) and 4.8% (n = 14), median time interval from surgery until adjuvant systemic therapy was 66 and 63 days, and 36 and 41 days until radiotherapy. Shortly postoperative, OP-BCS was associated with statistically significant lower mean scores for physical functioning (83.6 vs 87.2) and body image (82.8 vs 89.4) and more pain (19.8 vs 26.5) and breast symptoms (22.7 vs 30.3) than C-BCS. Body image scores remained significantly less favorable after OP-BSC than C-BCS up to 24 months postoperatively (87.8 vs 92.2). Conclusions Oncoplastic surgery safely enables BCS, but may lead to less favorable long-term body image compared to C-BCS. These findings are important for patient education and shared decision-making.