[High-dose conformal radiotherapy for glioblastoma multiforme]

The purpose of this study was to evaluate the impact of administering high doses by rotational multi-leaf collimator (MLC) conformal radiation therapy. From 1984 to 1995, thirty-five consecutive cases with glioblastoma multiforme were treated using rotational MLC conformal therapy. There were 23 men and 12 women, with an average age of 45 years (12-73 years). Median Karnofsky performance score was 80(30-100). Median tumor volume was 56 cc (8-800 cc). All patients underwent surgical intervention (only biopsy in one, partial resection in 13, subtotal resection in 18, and gross total resection in three). Radiation dose ranged from 60 to 80 Gy (mean 68.5 Gy) in 21 patients treated before 1991, and was 90 Gy in the 14 patients treated thereafter. Biweekly intravenous chemotherapy was also administered in both arms. The 1-year, 2-year, and 5-year survival rates were 72%, 43%, and 21%, respectively. Residual tumor volume was the only statistically significant factor for survival by multivariable analysis. The five-year survival rate of patients with residual tumors 2 cm or less in diameter was as high as 44%. Local failure was observed in 15 of the 18 patients in the lower dose group, whereas it was observed in only 4 of the 10 patients in the higher dose group. The difference was statistically significant. Rotational conformal therapy in combination with intensive surgical resection showed a favorable outcome. However, increased dose did not lead to higher survival rate.