Analysis of the discontinuation and nonpublication of neurooncological randomized clinical trials

Background. Premature discontinuation and nonpublication of clinical trials contribute to research waste and compromise our ability to improve patient outcomes. However, the extent to which these problems exist in neurooncological randomized clinical trials (RCTs) is not known. This study aimed to evaluate the prevalence of discontinuation and nonpublication of neurooncological RCTs, identify contributing factors, and assess trial characteristics associated with each. Methods. We performed a retrospective, cross-sectional study of neurooncological RCTs registered in Clinicaltrials.gov before March 7, 2023. Data were collected from Clinicaltrials.gov and associated publications were located. We attempted to contact authors for all trials without associated publications or an identified reason for discontinuation. Results. Of 139 included RCTs, 57 (41%) were discontinued. The most common reason for discontinuation identified was slow enrollment or accrual (23%), though 30 trials (53%) were discontinued for unknown reasons. Trials funded by sources other than industry or the National Institutes of Health were more likely to be discontinued (odds ratio 4.2, 95% confidence interval 1.3-13.8). In total, 67 of the 139 (48%) RCTs were unpublished, including 50 of the 57 (88%) discontinued studies and 17 of the 82 (21%) completed studies. Conclusions. In our study, discontinuation of neurooncological clinical trials was common and often occurred for unknown reasons. Trials were also frequently unpublished, particularly those that were discontinued. Addressing these findings may provide an opportunity to reduce research waste and improve outcomes for patients with neurological cancers.