Hypofractionated Versus Conventional Postmastectomy Radiotherapy in Implant-Based Breast Reconstruction: A Systematic Review and Meta-Analysis

Background/Objectives: The safety of hypofractionated postmastectomy radiotherapy (HF-PMRT) in patients undergoing implant-based breast reconstruction remains uncertain because of concerns regarding radiation-related reconstructive complications. We conducted a systematic review and meta-analysis to compare reconstruction-related complications following HF-PMRT versus conventionally fractionated (CF) PMRT. Methods: PubMed, Cochrane Library, and EMBASE databases were searched through August 2025 following PRISMA guidelines. Studies comparing HF-PMRT with CF-PMRT in patients undergoing implant-based breast reconstruction were included. Outcomes were capsular contracture, implant or tissue expander removal, infection, and wound dehiscence. Risk of bias was assessed using RoB 2 and ROBINS-I tools. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using the Mantel–Haenszel method. Subgroup analyses were performed by reconstruction stage (tissue expander vs. permanent implant). Results: Seven studies (n = 2200 patients; 1153 HF, 1047 CF) were analyzed, comprising two randomized controlled trials and five retrospective cohort studies. HF-PMRT was associated with a significantly lower risk of capsular contracture (OR 0.65, 95% CI 0.47–0.92) and wound dehiscence (OR 0.39, 95% CI 0.16–0.94) than CF-PMRT. Implant or tissue expander removal (OR 0.90, 95% CI 0.67–1.22) or infection (OR 0.98, 95% CI 0.67–1.44) did not differ. In subgroup analyses, reduction in capsular contracture was most evident when PMRT was delivered during the tissue expansion phase. Conclusions: These findings suggest that moderate hypofractionation is a reasonable fractionation option for implant-based breast reconstruction, with no evidence of increased reconstructive complications, although the certainty of evidence was limited, and prospective validation is warranted.