Designs of preoperative biomarkers trials in oncology: a systematic review of the literature

Preoperative biomarkers trials are infrequent but safe and feasible. These trials often permit the identification of predictive and pharmacodynamic biomarkers. However, designs of these trials certainly need to be improved. Background: The identification of predictive and pharmacodynamics (PD) biomarkers of efficacy of anticancer-targeted therapies is not always straightforward. To address this problem, preoperative trials have been set up. The present study aimed at evaluating how these trials are designed. Design: We retrieved all preoperative oncology trials, defined as preoperative trials having a PD end point. Results: Only 56 trials met our selection criteria. Of these, 27 trials (48%) were randomized. Forty-nine trials (88%) evaluated at least a noncytotoxic agent. In 37 trials (66%), a single agent was administered. The most prevalent tumor type was breast cancer (59%). Median duration of accrual was 28 months (range: 9-98). In these trials, there was a mean of two patients included per month (range: 0-7). The date of surgery was fixed before study entry in 35 trials (62%), while surgery was set up after preoperative therapy in the remaining 21 trials (38%). In the former trials, median duration of preoperative therapy was 17 days (range: 1-112), whereas in the latter trials it ranged from 4 to 29 weeks. The primary end point was a PD end point in 26 of the 45 trials (58%) in which it was mentioned. One percent of patients could not undergo surgery as per protocol due to an adverse event. Statistically significant predictive and PD biomarkers were identified in 17 (30%) and 27 trials (48%), respectively. Conclusion: Preoperative biomarkers trials are infrequent but safe and feasible. These trials often permit the identification of predictive and PD biomarkers.