Clinical trial registry use in minimally invasive surgical oncology systematic reviews and meta-analyses.

Publication bias can arise in systematic reviews when unpublished data are omitted and lead to inaccurate clinical decision making and adverse clinical outcomes. By conducting searches of clinical trial registries (CTRs), researchers can create more accurate systematic reviews and mitigate the risk of publication bias. The aims of this study are: to evaluate CTR use in systematic reviews and meta-analyses within the minimally invasive surgical oncology (MISO) literature; to conduct a search of ClinicalTrials.gov for a subset of reviews to determine if eligible trials exist that could have been used. This is a cross-sectional study of 197 systematic reviews and meta-analyses retrieved from PubMed. Of 137 included studies, 18 (13.1%) reported searching a CTR. Our ClinicalTrials.gov search revealed that of the 25 randomly selected systematic reviews that failed to conduct a trial registry search, 16 (64.0%) would have identified additional data sources. MISO systematic reviews and meta-analyses do not regularly use CTRs in their data collection, despite eligible trials being freely available.