Role of Postoperative Conventional Radiation Therapy in the Management of Supratentorial Malignant Glioma : with respect to survival outcome and prognostic factors

Nam, Taek Keun; Chung, Woong Ki; Ahn, Sung Ja; Nah, Byung Sik

Abstract

PURPOSE: To evaluate the role of conventional postoperative adjuvant radiotherapy in the management of supratentorial malignant glioma and to determine favorable prognostic factors affecting survival. MATERIAL AND METHODS: From Sep. 1985 to Mar. 1997, the number of eligible patients who received postoperative radiotherapy completely was 69. They ranged in age from 7 to 66 years (median, 47). Forty-two (61%) patients were glioblastoma multiforme and the other 27 (39%) were anaplastic astrocytoma. Twenty patients (29%) had Karnofsky score equal or more than 80 preoperatively. Forty-three patients (62%) had symptom duration equal or less than 3 months. Twenty-four patients (35%) had gross total resection and forty patients(58%) had partial resection, the remaining five patients (7%) had biopsy only. Radiotherapy dose ranged from 50.4 Gy to 61.2 Gy (median, 55.8; mode, 59.4) with fraction size of 1.8 Gy-2.0 Gy for 33-83 days(median, 48) except three patients delivered 33, 36, 39 Gy, respectively with fraction size of 3.0 Gy due to poor postoperative performance status. Follow-up rate was 93% and median follow-up period was 14 months.
RESULTS
Overall survival rate at 2 and 3 years and median survival were 38%, 20%, and 16 months for entire patients; 67%, 44%, and 34 months for anaplastic astrocytoma; 18%, 4%, and 14 months for glioblastoma multiforme, respectively (p=0.0001). According to the extent of surgery, 3-year overall survival for gross total resection, partial resection, and biopsy only was 38%, 11%, and 0%, respectively (p=0.02). The 3-year overall survival rates for patients age 40>, 40-59, and 60< or = were 52%, 8%, and 0%, respectively (p=0.0007). For the variate of performance score 80< or = vs 80>, the 3-year survival rates were 53% and 9%, respectively (p=0.008). On multivariate analysis including covariates of three surgical and age subgroups as above, pathology, extent of surgery and age were significant prognostic factors affecting overall survival. On another multivariate analysis with covariates of two surgical (total resection vs others) and two age (50> vs 50< or =) subgroups, then, pathology, extent of surgery and performancestatus were significant factors instead of age and 3-year cumulative survival rate for the five patients with these three favorable factors was 100% without serious sequela.
CONCLUSION
We confirmed the role of postoperative conventional radiotherapy in the management of supratentorial malignant glioma by improving survival as compared with historical data of surgery only. Patients with anaplastic astrocytoma, good performance score, gross total resection and/or young age survived longest. Maximum surgical resection with acceptable preservation of neurologic function should be attempted in glioblastoma patients, especially in younger patients. But the survival of most glioblastoma patients without favorable factors is still poor, so other active adjuvant treatment modalities should be tried or added rather than conventional radiation treatment alone in this subgroup.