Quality-adjusted survival analysis of malignant glioma. Patients treated with twice-daily radiation (RT) and carmustine: A report of radiation therapy oncology group (RTOG) 83-02

Abstract

To quantify the quality of life of malignant glioma patients treated on a randomized Phase I/II trial of twice-daily radiation therapy (RT) and carmustine, using a modified quality adjusted survival (QAS) model, and to compare the QAS among assigned treatment arms. The Radiation Therapy Oncology Group (RTOG) accrued 786 malignant glioma patients to a Phase I/II randomized dose escalation trial of twice-daily RT with carmustine from 1983 to 1989. Patients were randomized to one of four arms of hyperfractionated RT in 1.2 Gy twice daily (BID) fractions (64.8 Gy, 72.0 Gy, 76.8 Gy, or 81.6 Gy) or to either of two accelerated hyperfractionated RT arms in 1.6 Gy BID fractions (48.0 or 54.4 Gy). Although preliminary toxicity and survival data have been published, little information is available regarding the quality of these patients' lives during and following such therapy. QAS is a refinement of the methodology for assessing survival quality among breast cancer patients receiving adjuvant chemotherapy. The QAS method allows for inclusion of both improvement and decline in neurologic functional status. Patients were scored by the presence or absence of 15 neurologic signs and symptoms at on-study and at every follow-up. Within each category were gradations of severity, with the quality survival time (Q-TIME) adjusted according to any changes in these neurologic findings. The summation of all changes in signs and symptoms were weighted by 1/15th and incorporated into the QAS model as QAS = Q-TIME-TOX-RRX. TOX was the time spent with treatment-related toxicities, and RRX was the time spent in recovery from subsequent therapy. Of 747 evaluable patients, the average QAS time was 18.5 months. The average QAS for the hyperfractionated arms of 64.8 Gy, 72.0 Gy, 76.8 Gy, and 81.6 Gy were 15.6, 20.8, 10.0, and 13.7 months, respectively. For the accelerated hyperfractionated RT arms of 48.0 and 54.4 Gy, the average QAS times were 13.1 and 13.4 months. The QAS time of the 72.0 Gy arm was significantly longer than that of all other groups, except the 64.8 Gy arm. As expected, the QAS times were strongly discriminated by both age and Karnofsky Performance Scores (KPS) (p < 0.001). Younger patients and patients with high KPS benefited most from assignment to the 72.0 Gy arm; QAS time was not significantly longer in any treatment arm among patients over age 50 or with KPS scores of 80 or less. This quality-adjusted survival methodology can be successfully applied to malignant glioma patients and permits a quantitative assessment of the influence of investigational therapies on patient quality of life. This analysis confirms the potential benefit of intermediate dose (72.0 Gy) hyperfractionated RT for selected malignant glioma patients.