Efficacy of High Dose Radiotherapy in Post-operative Treatment of Glioblastoma Multiform - A Single Institution Report

Background: Glioblastoma multiform (GBM) is a highly aggressive tumor with median survival ofapproximately 14 months. Management consists of maximal surgical resection followed by post-operativechemoradiation with concurrent then adjuvant temozolamide. The standard radiotherapy dose is 60Gy in 2-Gyfractions recommended by the radiation therapy oncology group (RTOG). With the vast majority of tumorrecurrences occurring within the previous irradiation field and the poor outcome associated with standardtherapy, regimens designed to deliver higher radiation doses to improve local control and enhance survival areneeded. In this study, we report a single institutional experience in treatment of 68 consecutive patients withGBM, treated with resection, and given post-operative radiotherapy followed by concurrent and/or adjuvantchemotherapy.
Results: Of the 80 patients who entered this study, 68 completed the treatment course; 45 (66.2%)males and 23 (33.8%) females with a mean age at diagnosis of 49.0±12.9 (21-75) years. At a median follow up of19 months, 39 (57.3%) patients had evidence of tumor progression and 36 (52.9%) had died. The median overall survival for all patients was 16 months and progression free survival for all patients was 6.02 months. Allpotential prognostic factors were analyzed to evaluate their effects on overall survival. Age ≤50 year, concurrentand adjuvant chemotherapy and extent of surgery had significant p values. We found lower progression rateamong patients who received higher doses of radiotherapy (>60Gy). Higher radiation doses improved progressionfree survival (p=0.03). Despite increasing overall survival, this elevation was not significant.
Conclusions: Thisstudy emphasize that higher radiation doses of (>60Gy) can improve local control and potentially survival, sowe strongly advise prospective multi centric studies to evaluate the role of higher doses of radiotherapy on GBMpatient outcome.