High-Dose Vitamin D in Combination With Chemoradiotherapy in the Treatment of Glioblastoma Multiforme

This is non-randomized phase 2 study to assess efficacy and toxicity of long term high dose vitamin D3 given concurrently with chemo-radiotherapy (CCRT) containing temozolomide followed by adjuvant chemotherapy (ACT) with temozolomide in patients with newly diagnosed glioblastoma multiforme GBM). Preoperative diagnosis of GBM will be based on magnetic resonance imaging (MRI) brain scan. All patient will underwent craniotomy with partial or total resection of a visible tumour mass. All patients will be planned for postoperative three-dimensional conformal RT (3-DCRT) or intensity-modulated RT (IMRT) to residual tumour and/or resection bed. A total RT dose of 54-60 Gy will be delivered using 2 Gy daily fractions given over 5 days a week. Daily chemotherapy with temozolomide in the dose of 75 mg/m2/day will be started at the first day of RT, and will be continued for entire period of RT inclusive week-end breaks. ACT will contain 6 cycles of oral temozolomide 150-200 mg/m2/day given for 5 days every 4 weeks. Oral vitamin D3 will be administered in daily dose of 4000 IU. Vitamin D3 therapy will be started 1 week prior to commencing CCRT, and will be terminated immediately after completing last cycle of ACT. MRI scan of the brain will be performed at 4 months after completing CCRT, and than will be repeated every 4 months for first 2 years, and every 6 months for subsequent years. The study participants will be followed until disease progression or death. The study is expected to complete within 4 years.