3D Conformal Re-Irradiation with Temozolamide for Recurrent Glioblastoma: A Prospective Cohort Study

Abstract

Introduction and objectives: Salvage treatment of recurrent Glioblastoma (GBM) is one of the most challenging tasks in neuro-oncology. There is no standard treatment for recurrent GBM as options include resection, chemotherapy, and re-irradiation either separate or in combination. Role of concomitant temozolamide with re-irradiation in recurrent disease is still debatable. Therefore, this study evaluate s efficacy of concurrent and adjuvant temozolamide with re-irradiation in management of recurrent GBM. Patients and methods: Twenty two patients with recurrent glioblastoma were eligible. Patients were treated with 3 D conformal radiotherapy. The dose ranged from 30 to 40 Gy in 1.6 to 1.8 Gy per fraction for 5 days per week. Temozolamide was administrated at 50 mg/m 2 daily dose during radiation therapy. Adjuvant Temozolomide (200 mg/m 2 ) was given orally for five days every four weeks for 4 - 6 cycles for patients who did not receive temozolamide before, and 150 mg/m 2 for pretreated patients. Results: 22 patients received re-irradiation with median dose 38 Gy (range 33 - 40 Gy), concurrent with temozolamide. The time interval between primary and re-irradiation ranged from 6 to 23 months with median 12 months. The re-irradiated volume, median was 101.95 cm 3 (range 30 - 375 cm 3 ). The median cumulative maximum dose to optic system and brain stem were 53.5 Gy (range 42 - 63 Gy), and 60 Gy (range 54 - 73 Gy), respectively. Response rate was 72.7%, one patient showed complete response (4.5%), partial response and stable disease registered in 22.7% and 45.5%, respectively. The median overall survival (OS) was 10 months (range 4 - 13 months), and median progression-free (PFS) survival was 7.5 months (range 2 - 11 months). The 6 and 12 months OS rate was 100% and 56.6% respectively, and the 6 months PFS rate was 93.3%. No major acute toxicity was observed. About 70% of patients experienced grade 2 toxicity in the form of headache, nausea & vomiting, skin erythema and alopecia. The late toxicity was minimal as GI & II. Symptoms of radiation necro sis were not recorded in any patient. Conclusion: 3D conformal re-irradiation concomitant with temozolamide and adjuvant temozolamide appears effective treatment in recurrent glioblastoma. The treatment protocol is safe, feasible treatment with limited rate of toxicity and improve survival outcome.