When progression-free survival fails to inform: the need for event-level reporting in oligometastatic radiotherapy trials.

Progression-free survival treats biologically and clinically distinct progression events equivalently, limiting its interpretability in oligometastatic radiotherapy trials. Across 21 randomized trials, event-level reporting was frequently absent, and none described how post-radiotherapy imaging was adjudicated within PFS. Pragmatic reporting standards could improve interpretation without requiring new endpoints or altered trial design.