Background: Intensity-modulated radiotherapy (IMRT) using the simultaneous integrated boost (SIB) method was designed for treating malignant gliomas. The purpose of this study was to investigate feasibility of this treatment.
Methods: Between December 2000 and November 2002, six patients with malignant gliomas were enrolled in this study. IMRT delivered 70 Gy/28 fractions (fr)/daily 2.5 Gy to the gross tumor volume (GTV) and 56 Gy/28 fr/daily 2.0 Gy to the surrounding edema defined as the clinical target volume annulus (CTV-a). The feasibility of the treatment was assessed from both physical and clinical points of view.
Results: No delay due to acute radiation toxicity was observed in any of the patients. The tumor recurred locoregionally in five of the six patients. The glioblastoma (GBM) recurred in two patients during the radiotherapy and in three patients at 5.4, 4.0 and 7.0 months after the start of radiotherapy. The sites of recurrence or progression were local in the GTV in four patients and in one patient subependymal dissemination was observed. Three patients, two with GBMs and one with anaplastic astrocytoma, died of the disease at 4, 16 and 7 months after the start of radiotherapy, respectively.
Conclusions: The treatment of 70 Gy/28 fr/daily 2.5 Gy to the GTV and 56 Gy/28 fr/daily 2.0 Gy to the CTV-a was feasible both physically and clinically.