Hypofractionated radiotherapy with concurrent temozolomide chemotherapy in patients with newly diagnosed RPA class V glioblastoma multiforme: promising early results

Objective This study reports the initial results of hypofractionated radiation therapy (HFRT) with concurrent/adjuvant temozolomide (TMZ) for glioblastoma multiforme (GBM) patients with especially poor prognoses. Methods Sixteen patients with GBM and Radiation Therapy and Oncology Group (RTOG) recursive partitioning analysis (RPA) class V who underwent maximally safe resection or biopsy (when considered inoperable), followed by HFRT/TMZ, during 2011–2014 were analyzed. HFRT was given in six treatments over 2 weeks using dose painting: 6 × 6 Gy to contrast-enhancing tumor + 5 mm (CTV1) and 6 × 4 Gy to FLAIR hypersignal + 2 cm (CTV2), plus 5-mm expansion for both PTVs. HFRT was delivered concomitantly with TMZ (75 mg/m 2 daily), followed by adjuvant TMZ (150–200 mg/m 2 in 5/28 days). Results Median age was 65 years (50–82) and Karnofsky performance status (KPS) was 60 (40–80). Median pre-op gross tumor maximum dimension on MRI was 4.8 cm (1.8–8.5 cm). Four patients had gross total resection, six had subtotal resection, and six had biopsy only. The treatment was well tolerated without non-hematologic grade 3/4 acute toxicities. No increase in dexamethasone dosage was required in any of the patients during HFRT. With a median follow-up of 9 months (1–28), there were 12 (75 %) recurrences/progressions and 6 (38 %) deaths. Yet, 6 (38 %) patients exceeded survival of 1 year, and 4 were alive as of the latest follow-up at 12, 14, 27, and 28 months. Median survival was 14 months, while median progression-free survival was 5 months. Conclusion The HFRT/TMZ regimen was safe, well tolerated, and convenient for GBM patients with the poorest prognosis, rendering a shorter overall treatment time and no increase in toxicity.