Executive Summary of the American Radium Society Appropriate Use Criteria for Selective Use of Pelvic Radiation...

Pelvic radiotherapy is commonly incorporated in the treatment of locally-advanced rectal cancer to reduce the risk of locoregional recurrence, but can be associated with substantial acute toxicity and long-term morbidity. However, treatment may be personalized for selective use of radiotherapy in a subset of patients identified to be at low to intermediate risk of locoregional recurrence following resection. This multi-specialty-led committee included gastrointestinal radiation and medical oncology, gastroenterology, radiology, and colorectal surgery. Using the Population, Intervention, Comparator, Outcome, Timing and Study Design (PICOTS) framework, evidence regarding treatment outcomes was assessed using Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Eligible studies included prospective and retrospective (n ≥ 50) studies published between 1/1/2005 - 6/24/2025 from Embase, Medline and PubMed databases. Study type and quality were assessed. Well-established RAND corportaion/University of California Los Angeles (RAND-UCLA) consensus methodology (modified Delphi) was used to rate the appropriateness of the treatment options. Of the 110 articles identified using the search strategy, 35 were selected that met all inclusion criteria. Of the 35 references used as evidence, 35 are categorized as therapeutic including 14 well-designed studies (Phase II randomized and Phase III), 12 moderately well-designed studies that account for most common biases (matched cohort and Phase II studies), 7 studies with design limitations (retrospective reviews), and 3 meta-analyses. Variant cases were developed as examples to illustrate practical applications of consensus recommendations for when RT can be safely omitted. A treatment algorithm is also provided to assist with treatment decisions when considering selective use of pelvic RT.