Abstract PS2-03-14: Autologous versus Implant-Based Breast Reconstruction: Complication and corrective surgery rates with and without Radiotherapy

Abstract Background: Although radiotherapy (RT) significantly improves oncological outcomes of patients with high-risk breast cancer, it also increases complication rates and the need for corrective surgical procedures in patients undergoing breast reconstruction. The authors hypothesize that RT impacts complication rates and the need for corrective surgical procedures, especially in implant-based breast reconstruction (IBR) compared to autologous breast reconstruction (ABR). Methods: A retrospective review of consecutive patients treated at the Institute of Oncology Ljubljana and University Medical Centre Ljubljana with mastectomy and ABR or IBR in the year 2019, with or without RT, was conducted. Complication and corrective surgery rates were compared between ABR and IBR. The associations between categorical variables were investigated using Pearson's chi-square test and multivariate analysis. A two-tailed test was used to identify significant differences with a p-value of ≤0.05. Results: In 2019, we identified 219 patients who underwent breast reconstruction; among them, 153 (69.5%) had unilateral reconstructions and 66 (30.5%) had bilateral reconstructions, resulting in a total of 285 breast reconstructions, with 106 (37.2%) being ABR and 179 (62.8%) being IBR. Most patients (87.7%) had immediate breast reconstruction. Risk-reducing surgery was done in 30.2% of reconstructions. Eighty-nine (31.2%) breast reconstructions underwent RT, of whom 46 had IBR and 43 had ABR. Twenty-eight (9.8%) reconstructed breasts received preoperative RT. We detected 22.1% of early complications and 6.3% of late complications. Patients who had preoperative RT and IBR experienced early complications more often, with 18.8% of them affected compared to only 4.8% of those who did not have preoperative RT in IBR, p=0.014. For the analysis of corrective surgery rates, we excluded breast reconstructions that had delayed-immediate ABR (3.2%) and included 276 breast reconstructions for analysis. Patients who had ABR or IBR had similar rates of corrective procedures when compared, regardless of RT (25.8% ABR no RT vs 25.6% IBR no RT; 42.5% ABR with RT vs 36.6% IBR with RT). Overall, patients who received RT had more corrective surgeries (39.5% with RT vs 25.6% no RT, p=0.502), but the difference was not statistically significant. In subgroup analysis of unilateral reconstruction, we excluded patients that later received risk-reducing contralateral mastectomy with reconstruction, and detected a difference in the symmetrization rate according to the type of reconstruction (16.1% in ABR vs 50.8% in IBR; p0.0001). Although the difference in the symmetrization rate was detected between patients who received RT (36.8%) and those who did not (25.8%) (p=0.196), statistical significance was not observed. Conclusions: In patients with preoperative RT, IBR was associated with a higher probability of early complications. Breast reconstruction type selection does not influence the need for further corrective surgical procedures in patients receiving RT according to this analysis. Symmetrization surgery was more common after IBR. RT increases the need for symmetrization surgery in both reconstruction types. Citation Format: R. Cencelj-Arnez, T. Arnez, A. Perhavec, D. Ribnikar, I. Ratosa. Autologous versus Implant-Based Breast Reconstruction: Complication and corrective surgery rates with and without Radiotherapy abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-03-14.