Screen Failure Rates in Contemporary Randomized Clinical Phase II/III Therapeutic Trials in Genitourinary Malignancies.

BACKGROUND: Screen failures, defined as individuals who undergo screening but are not enrolled in a clinical trial, incur significant costs without contributing valuable data to the study. Despite these costs, there are few published data about the rate or reasons for screen failures in advanced genitourinary cancer clinical trials.

MATERIALS AND METHODS: We reviewed 50 phase II and III trials in advanced genitourinary cancers conducted between 1999 and 2016.

RESULTS: Of the 50 trials, only 48% (24 of 50) published screen failure rates: 68% (13 of 19) of those in prostate cancer, 33% (6 of 18) in kidney cancer, and 58% (5 of 13) in bladder cancer. Among the phase III trials in prostate cancer, the mean screen failure rate was 26% (range, 12%-45%). The main reason for screen failure was reported as ineligibility. Among the phase III trials in kidney cancer, the mean screen failure rate was 25% (range, 21%-29%), with the most frequent reasons being ineligibility and patient refusal. Among the phase II/III trials in bladder cancer, the mean screen failure rate was 19% (range, 4%-28%), with the main reasons being ineligibility and patient refusal.

CONCLUSION: Contemporary trials in genitourinary cancer reported screen failure rates of approximately 20% to 30%. Many trials did not report on the numbers of, and reasons for, screen failures. Greater standardization of definitions, methods, and reporting are needed to better understand and decrease screen failure rates in genitourinary cancer clinical trials.