Prospective Comparison of Long-Term Outcomes in Prepectoral vs. Subpectoral Implant Breast Reconstruction After Post-Mastectomy Radiotherapy

BACKGROUND: Prepectoral implant-based breast reconstruction (PP-IBR) is increasingly favored over subpectoral reconstruction (SP-IBR) to reduce animation deformity, yet data regarding its outcomes after post-mastectomy radiotherapy (PMRT) are limited. This study aims to prospectively compare long-term outcomes of PP-IBR and SP-IBR following PMRT. METHODS: Data were obtained from the multicenter randomized trial, Study of Radiation Fractionation on Patient Outcomes After Breast Reconstruction (FABREC). Complications, aesthetic results, and patient-reported outcomes (PROs) were assessed. The FACT-B and Breast-Q Reconstruction Module were administered, and aesthetic outcomes were evaluated by blinded reviewers at 6 and 18 months following PMRT. Multivariable analysis was performed to evaluate whether PP-IBR vs. SP-IBR was associated with outcomes after controlling for other covariates. RESULTS: Among 380 patients, 224 underwent PP-IBR and 156 SP-IBR. Demographics were similar, except SP-IBR had a higher proportion of tissue expanders and lower body mass index (BMI). There were no significant differences in PROs, including physical, social, emotional, and functional well-being (FACT-B), or satisfaction with breasts, psychosocial well-being, sexual well-being, and physical well-being (BREAST-Q), at both timepoints. Higher BMI was associated with lower sexual well-being at both 6 and 18 months (Estimate -0.60, p=0.03). At 6 months, SP-IBR was linked to lower aesthetic scores compared to PP-IBR; however, only age remained a significant predictor at 18 months (Estimate -0.02, p=0.00). CONCLUSION: In PMRT settings, both PP-IBR and SP-IBR exhibit comparable complication rates and long-term aesthetic and PRO outcomes. Patient factors, such as age and BMI, appear to play a more prominent role in overall outcomes.