Impact of a dosimetry review program on radiotherapy in group trials.

The impact of a quality assurance program on protocol compliance has been explored. A sample of 2258 patients, who received radiation therapy on 18 different NCI funded protocols, was selected for this study from the more than 6200 cases reviewed by the Quality Assurance Review Center (QARC) from 1974 to 1983. Analysis of this sample reveals a significant decrease in the protocol non-compliance rate as a function of QA participation time (35% down to 5%). The educational impact of the QA program is demonstrated by the drop in the protocol dose deviation rate from 11.4% (before QARC feedback) to 3.6% (after feedback, p less than .001). The corresponding drop in protocol deviations in treatment volume is from 21.5% to 10.5% (p less than .001). The effect of the "on-treatment" review process is studied; it is demonstrated that this process cuts the rate of major deviations in half. The technical discrepancies in dose are also analyzed and discussed.