Quality control of radiotherapy in acute lymphocytic leukemia protocol treatment: experience with 610 cases

Quality assurance programs are necessary in multi-institutional cooperative group clinical trials to ensure that possible inter-institutional differences in selection, treatment and evaluation of patients will not erode the statistical assessment of these clinical trials. The Radiotherapy Committee of the Cancer and Leukemia Group B examined the evaluability and appropriateness of treatment of patients entered into two protocols for childhood acute lymphocytic leukemia, 7411 prior to and 7611 after the development of a quality assurance review program. Of the 348 patients entered into 7411, 37% were evaluable and 26% were appropriately treated in 1974 when the protocol opened. This rose to 53 and 35% in the last year of the study. On the other hand, in 7611 with an ongoing quality assurance program, the evaluability rate initially was 63% and rose to 73% and the appropriateness rate rose from 37 to 61%. This change in performance which was statistically significant at the P = 0.001 level is attributed to the impact of the Quality Assurance Review Center correspondence. Improvement in performance occurred almost entirely in the principal centers and not in satellite institutions. This difference in performance was statistically significant at the P = 0.05 level, indicating that adherence to protocol requirements increases with increased participation in studies.