Introduction: Recent American College of Sports Medicine (ACSM) published exercise guidelines to support prescription recommendations for a range of health-related cancer outcomes have been adopted worldwide. The evidence for these guidelines is mostly informed by trials undertaken in populations with common cancers, good prognosis and ‘generally well’ samples, with poor reporting of safety. As exercise oncology trials progress to involve more representative samples of the wider cancer population, it is increasingly important for clear safety recording and reporting protocols to capture the potential harms as well as benefits of exercise in more at-risk cancer populations.

Aims: To describe how adverse events (AE) were assessed and reported in trials that informed evidence-based exercise oncology prescription guidelines and to identify steps required for future improvement.

Methods: A rapid review of original research that informed the ACSM exercise guidelines for cancer health-related outcomes with strong supporting evidence was undertaken. Data including study characteristics and AE assessment and reporting procedures were extracted.

Results: Findings from pre-post, randomised and non-randomised trials from 285 papers informed the guidelines and were identified to undergo data extraction. Preliminary findings from the first 50 papers indicate that 46% (n = 23) of trials reported AE. Even fewer papers (n = 40) reported how they assessed AE. Of those that reported AE, 39% (n = 9/23) reported no AE occurred but did not specify how AE were recorded. The methodology of AE assessment and reporting was often described in a single statement.

Conclusions: Preliminary analysis suggests that assessment and reporting of AE in exercise oncology trials is poor. Without comprehensive data of exercise safety, clinicians cannot adequately discuss the potential harms and benefits of exercise with cancer patients to inform treatment decisions. A standardised approach to assessing and reporting AE in exercise oncology trials is needed as exercise becomes more widely embedded in oncology care.