Surgical outcomes of post-mastectomy radiotherapy following immediate prosthetic breast reconstruction: six-year experience

Abstract

PROBLEM STATEMENT: The utilisation of post-mastectomy radiotherapy (PMRT) following immediate prosthetic breast reconstruction is increasing as the indications for its use are expanding. It is important for both patients and treating teams to understand the potential impacts of PMRT on prosthetic breast reconstruction outcomes. METHODS: A single-institution retrospective analysis of surgical outcomes on consecutive patients who underwent PMRT following skin- or nipple-sparing mastectomy with immediate prosthetic breast reconstruction (two-stage or direct-to-implant) between January 2015 and December 2020 was completed. RESULTS: A total of 94 cases were included. Prosthesis placement was pre-pectoral in 33 cases (35.1%). Median follow-up was 40 months (range: 5-79 months). PMRT consisted of 50Gy in 25 fractions over five weeks to the neo-breast and supraclavicular fossa in the majority of cases (90%), with a permanent implant in-situ in 58 cases (61.7%). After accounting for the different combinations of sub/pre-pectoral implant placement, direct-to-implant/two-stage reconstruction and PMRT to permanent implant/expander, six different clinical pathways were identified. In the short term (within 60 days), infection was the most common complication (n=19, 20%), of which the salvage rate was 100% after mastectomy (n=8/8) and 43% after radiotherapy (n=3/7). In the long-term (after 60 days), the most common complication was moderate/severe capsular contracture (n=37, 39%). After completing the clinical pathway, over a third of patients (n=34, 36%) underwent at least one episode of autologous fat grafting. Subsequent revision of the breast pocket was undertaken in 7 cases (7%). Unplanned conversion to autologous reconstruction occurred in 14 cases (15%). The reconstruction failure rate (loss of implant and no conversion to autologous reconstruction) was 5% (n=5). Although no statistically significant difference was observed between the six different clinical pathways, unfavourable trends were observed with outcomes of direct-to-implant sub-pectoral and two-stage pre-pectoral reconstruction. CONCLUSIONS: This study suggests that PMRT following prosthetic-based reconstruction is feasible and that the method of reconstruction may not significantly influence surgical outcomes. Patients need to be counselled about the more common long-term risk of moderate/severe capsular contracture.