Impact of Prepectoral versus Subpectoral Tissue Expander Placement on Outcomes in Delayed-Immediate Autologous Patients Who Undergo Postmastectomy Radiation Therapy

Background: Delayed-immediate autologous (DIA) breast reconstruction is a safe and flexible operative strategy for patients undergoing postmastectomy radiation therapy (PMRT). Traditionally, tissue expanders (TE) are placed in the subpectoral position, but the development of acellular dermal matrix material has led to increased use of prepectoral placement strategies. Our aim was to compare the outcomes of both TE placement strategies in DIA patients who underwent PMRT and determine whether they experienced outcomes similar to those in non-PMRT patients. Methods: A retrospective analysis of four patient groups (314 total patients) who underwent DIA reconstruction from 2012 to 2019 was performed. Ninety-eight non-PMRT prepectoral (PP), 106 non-PMRT subpectoral (SP), 39 PMRT PP, and 71 PMRT SP patients were compared. Demographics, TE complications, flap complications, and the use of large inferior skin patches were analyzed. Results: A significantly lower percentage of the PMRT PP cohort required large inferior skin patches (30.6% versus 55.7%; P < 0.05) and multiflap procedures (15.4% versus 47.9%; P < 0.001) than the PMRT SP cohort. PMRT (P < 0.0001), SP placement (P < 0.05), body mass index (P < 0.05), autoimmune diseases (P < 0.05), and bilateral mastectomy (P < 0.001) were identified as factors predictive of patients requiring a large inferior patch by means of multivariable analysis. More SP patients experienced flap postoperative breast complications compared with PP patients (35.8% versus 12.2%; P < 0.0001). Conclusion: DIA patients who undergo PMRT will require more skin and flaps if SP TE placement is chosen over PP TE placement.