American Radium Society Appropriate Use Criteria Postmastectomy Radiation Therapy: Executive Summary of Clinical Topics.

PURPOSE: To conduct an appropriate use criteria expert panel update on clinical topics relevant to current clinical practice regarding postmastectomy radiation therapy (PMRT). METHODS AND MATERIALS: An analysis of the medical literature from peer-reviewed journals was conducted from May 4, 2010 to May 4, 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to search the PubMed database to retrieve a comprehensive set of relevant articles. A well-established methodology (modified Delphi) was used by the expert panel to rate the appropriate use of procedures. RESULTS: Evidence for key questions in PMRT regarding benefit in special populations and technical considerations for delivery was examined and described. Risk factors for local-regional recurrence in patients with intermediate-risk disease that indicate benefit of PMRT include molecular subtype, age, clinical stage, and pathologic response to neoadjuvant chemotherapy. Use of hypofractionated radiation in PMRT has been examined in several recent randomized trials and is under investigation for patients with breast reconstruction. The use of bolus varies significantly by practice region and has limited evidence for routine use. Adverse effects occurred with both PMRT preimplant and postimplant exchange in 2-staged breast reconstruction. CONCLUSIONS: Most patients with even limited nodal involvement will likely benefit from PMRT with significant reduction in local-regional recurrence and potential survival. Patients with initial clinical stage III disease and/or any residual disease after neoadjuvant chemotherapy should be strongly considered for PMRT. Growing evidence supports the use of hypofractionated radiation for PMRT with equivalent efficacy and decreased acute side effects, but additional evidence is needed for special populations. There is limited evidence to support routine use of bolus in all patients. Timing of PMRT regarding completion of 2-staged breast reconstruction requires a discussion of increased risks with radiation postimplant exchange compared with increased risk of failure of reconstruction or surgical complications with radiation preimplant exchange.