Scoping Review of Published Oncology Meta-analyses in High-Impact Oncology Journals

IMPORTANCE: Many meta-analyses have been conducted on a wide array of topics, and many of these have focused on treatment efficacy of drugs or bias in interventional studies on a specific topic. OBJECTIVE: To examine the factors associated with having a positive study conclusion in meta-analyses in the field of oncology. EVIDENCE REVIEW: All meta-analyses published between January 1, 2018, and December 31, 2021, on 5 oncology journal websites were identified and study characteristics, study results, and information on study authors were abstracted. The meta-analysis authors’ conclusions were coded as positive, negative, or equivocal, and each article subject matter was coded as one that could affect profits and marketing of a company. Whether an association existed between study characteristics and authors’ conclusions was also examined. FINDINGS: Database searches resulted in 3947 potential articles, of which 93 meta-analyses were included in this study. Of the 21 studies with author funding from industry, 17 studies (81.0%) reported favorable conclusions. Of the 9 studies that received industry funding, 7 (77.8%) reported favorable conclusions, and of the 63 studies that did not have author or study funding from industry, 30 (47.6%) reported favorable conclusions. Studies that were funded through nonindustry sources and authors who had no relevant conflict of interest had the lowest percentage of positive conclusions and the highest percentage of negative and equivocal conclusions compared with studies with other sources of potential conflict of interest. CONCLUSIONS AND RELEVANCE: In this cross-sectional study of meta-analyses published in oncology journals, multiple factors were associated with having a positive study conclusion, which suggests that future research should be performed to elucidate reasons for more favorable conclusions among studies with study or author industry funding.