Impact of neoadjuvant immunotherapy on postoperative complications in oncoplastic breast cancer surgery.

[BACKGROUND] Neoadjuvant pembrolizumab combined with chemotherapy is now standard treatment for stage II and III triple-negative breast cancer (TNBC). However, its impact on postoperative complications remains underexplored especially in oncoplastic or reconstructive procedures.

[METHODS] A retrospective before-and-after study was conducted at a single institution from January 2019 to May 2023. Patients with early-stage TNBC treated with chemotherapy alone (CT group) or chemotherapy plus pembrolizumab (CT + P group) were included. Postoperative complications (including delayed wound healing, abscesses, hematomas, infections, implant exposure, and skin necrosis) were compared using univariate and multivariate logistic regression.

[RESULTS] Among 254 patients (CT: n = 136; CT + P: n = 118), the overall complication rate was 15.7 %. No significant difference was observed between groups (p = 0.061). Delayed wound healing was more frequent in the CT + P group (10 % vs. 3.8 %, p = 0.031). After adjustment, immunotherapy was not independently associated with higher risk (OR 1.27, p = 0.5). Oncoplastic surgeries were associated with higher complication rates in univariate analysis but not in multivariate analysis (OR 1.74, p = 0.2). Complications were more frequent when surgery occurred <14 or >30 days post-treatment (p = 0.029), especially among CT + P patients (interaction p = 0.01).

[CONCLUSION] Neoadjuvant pembrolizumab does not significantly increase postoperative complications. Surgical timing appears to be a modifiable factor influencing outcomes.