Impact factor and citation metrics in phase III cancer trials

Journal impact factor (IF) is often used to measure research quality and importance. We assessed trial factors associated with the publication of cancer trials in journals with higher IF and publications receiving higher citations.

Cancer-specific phase III RCTs were screened through https://clinicaltrials.gov. We identified trials with published primary endpoints, along with their corresponding journal IF and relative citation ratio (RCR).

Seven-hundred ninety manuscripts were included in our study. Trials that met their primary endpoint were more commonly published in journals with higher IF (Median IF: positive trials 35.4 vs. negative trials 26.3, P < 0.001). Furthermore, trials that led to subsequent FDA drug approvals were also published in journals with higher IF (Median IF: 59.1 vs. 26.3 in trials not leading to FDA approvals, P < 0.001). When analyzing RCR, trial positivity (meeting primary endpoint) was not associated with increased citations on multivariable analysis (P = 0.56). Lastly, publications of trials leading to FDA approvals (P < 0.001), and publications of trials in journals with higher IF (P < 0.001) were associated with increased RCR.

Positive trials are commonly published in journals with high IF, but do not necessarily lead to increased citations. Moreover, trials published in journals with higher IF are more likely to receive increased citations.