Prognostic factors in glioblastoma patients managed with radiotherapy combined with temozolomide

Abstract

Purpose: No consensus on clinicopathologic prognostic factors that predict the outcome of patients with newly diagnosed glioblastoma multiforme (GBM) managed with resection, postoperative radiotherapy (RT) and adjuvant temozolomide (TMZ) exists today. The purpose of this study was to assess the outcome, compliance and toxicity in GBM patients treated with TMZ at our Center, as well as to evaluate factors with prognostic significance.

Methods: 91 GBM patients were enrolled in this retrospective study (2004-2012). 3D-conformal RT was given to a median total dose of 60Gy (daily dose 2Gy). Eighty nine (98%) of the patients received concurrent TMZ (75mg/m²) and 74 (81%) received adjuvant TMZ (150-200mg/m² for 5 days every 28 days) up to 12 cycles.

Results: At a mean follow up of 18.6 months, the median overall survival (OS) was 15.1 months. Grade 3/4 haematologic toxicity was observed in 19.8% of the patients while 4 patients (4.4%) experienced grade 3/4 non haematologic toxicity. In univariate analysis, significant correlation was found between OS and no/minor neurologic deficit at diagnosis (p=0.02), acute onset of symptoms (p=0.04) and 6 cycles of adjuvant TMZ (p<0.001). The addition of more than 6 cycles of TMZ did not offer any statistically significant survival benefit. In multivariate analysis, only the absence of major neurologic deficit remained associated with overall survival (p=0.016).

Conclusion: 3D conformal RT with TMZ achieved acceptable disease control with satisfactory compliance and toxicity. Intact neurologic function was associated with superior outcome, as a surrogate of low tumor burden, early treatment start and/or indolent tumor biology.