RTHP-10. PHASE II STUDY OF HYPO VS. CONVENTIONAL -FRACTIONATED RADIOTHERAPY WITH TEMOZOLOMIDE IN NEWLY DIAGNOSED GLIOBLASTOMA: EARLY COMPLIANCE AND TOLERANCE

Abstract

BACKGROUND: To compare possibility of delivering radiation in shorter course of time by hypo-fractionation in newly diagnosed GBM. METHODOLOGY: This phase II study intended to compare treatment outcome in newly diagnosed GBM patients, age ≥16 and ≤60 treated with conventional fractionated radiotherapy (60 Gy in 30 fractions) to hypo-fractionated radiotherapy (60 Gy in 20 fractions) with concurrent and maintenance Temozolomide after a maximal safe surgical resection. 50 patients were planned to randomize 1:1 in each of the study arm. The primary endpoints are response rate in each arm. Secondary endpoints are PFS, OS, and Toxicity ad compliance. RESULTS: 30 patients have been randomized so far. Median age was 38.5 years (Range: 16-59). Male: Female ratio was 2:1. 12(30%) patients had seizure at presentation. Median symptom duration was 2.5 months. 22 patients underwent a gross total resection whereas 8 patients underwent subtotal resection. Median MIB labeling index was 30% (Range: 8-95%). p53 deletion was noted on 50%, 20% patients had IDH-1 mutation, and 23% loss of ATRX immuno-expression. Only one patient required hospitalization for features of raised intracranial tension during radiation. All patients tolerated both the fractionation schedule without any treatment break. None of the patients had grade III or higher hematological toxicity both during the concurrent and adjuvant treatment with Temozolomide. At a median follow up of 8.31 months (Range: 3.97-24.89 months), 5 patients experienced local progression. However, none of the patients has a documented radio necrosis as of now. CONCLUSION: Hypofractionated radiation appears to be well tolerated with no treatment interruption. However, longer follow up of the study will be able to conclude the possibility of incorporating hypo fractionation in regular treatment of newly diagnosed GBM.