Variation in guideline decision-making: a cross-sectional study of oncology compendium panels

Introduction Clinical practice guidelines influence coverage policy, utilization management, and health care spending. In oncology, some function as drug compendia that guide Medicare coverage of off-label therapies, yet little empirical work has examined their governance. Methods We conducted a cross-sectional descriptive study using publicly available documentation to evaluate responses to 75 standardized external change requests submitted to 26 National Comprehensive Cancer Network (NCCN) disease-site panels concerning pembrolizumab or nivolumab dosing. Requests concerning subcutaneous formulations served as a comparator. We characterized request disposition, review timing, transparency, scope interpretation, and financial conflict-of-interest (FCOI) context. Results By March 6, 2026, 10 of 75 dosing-related requests (13%) had been adopted, 51 (68%) rejected or determined to be outside panel scope, and 14 (19%) remained pending (median time to decision, 190 days). In contrast, requests concerning FDA-approved subcutaneous formulations were adopted in 52 of 53 cases (98%) and reviewed substantially more rapidly (median, 11 days). Public documentation incompletely described panel deliberations, voting, participation, and management of financial conflicts of interest. Conclusions Standardized requests revealed operational heterogeneity and limitations in publicly available documentation within a CMS-recognized compendium, identifying opportunities to strengthen transparency and governance in coverage-relevant decision making.