Selection of large and objectively measurable target lesions in EORTC phase II trials: Impact on recruitment and response rate

Abstract

The EORTC has recently issued minimum requirements for target lesions in phase II trials, aiming at a decrease in measurement errors [minimum size, computer tomography (CT) scan or ultrasound for deep lesions]. Their impact on recruitment and response has been retrospectively studied in a trial of the EORTC Soft Tissue and Bone Sarcoma Group (STBSG), investigating high-dose chemotherapy in patients with advanced soft tissue sarcoma, where 46 103 objective responses were seen, including 10 complete responses. For the 20 patients who did not satisfy the criteria, a similar objective response rate and a significantly higher complete response rate were reported. Among 265 target lesions, the same trends were observed when comparing small to large lesions, for different tumour sites. For deep lesions clinically assessed, significantly higher response rates were reported than for those measured by CT scans or ultrasound. The new stricter EORTC criteria improve the reliability of measurements and have been adopted for future phase II trials of the STBSG. This will not result in the selection of potentially poor responders. Less than 20% of the present recruitment will be lost.