As clinical trials have important consequences for clinical practice, transparent results reporting is crucial. Registration of clinical trials and their endpoints in a publicly available register is therefore mandatory.

Serpas et al. (1) reviewed 71 oncology-related randomized controlled trials published in the Journal of Clinical Oncology, the New England Journal of Medicine, and The Lancet. They found discrepancies in the primary endpoint only in 4 trials (6%). Secondary endpoint differences were more common, in 45 (63%) trials. Of these, 36 (80%) had secondary endpoints that were planned in the protocol but not reported in the registry, and 19 (42%) had secondary endpoints defined in the registry but not in the protocol.

The authors conclude that further guidelines and greater efforts to provide a correct and complete representation of planned endpoints are needed.


  1. Serpas VJ, Raghav KP, Halperin DM, Yao J, Overman MJ. Discrepancies in endpoints between clinical trial protocols and clinical trial registration in randomized trials in oncology. BMC Medical Research Methodology 2018;18:169