Recurrent glioblastoma: a single-institution experience with reirradiation and temozolomide

Glioblastoma is an aggressive disease with poor prognosis. Outcomes following recurrences are dismal despite the use of multimodality treatment. Surgery is usually not a viable option, and even in those who do undergo surgery, adjuvant radiation therapy with or without concurrent chemotherapy may be viable options depending on several factors such as performance status, disease volume, and time since prior therapy. We intended to assess the efficacy of high precision reirradiation with temozolomide as a salvage modality in patients with recurrent glioblastoma.

Twenty-five patients with recurrent glioblastoma who received reirradiation (with or without concurrent temozolomide) for recurrence at our department between 2010 and 2015 were included in this retrospective analysis. Treatment decisions are taken following recommendations of multidisciplinary tumor board. Treatment details were noted from respective case records. Survival time was calculated using Kaplan-Meier method. Univariate and multivariate analyses were performed using Cox regression analysis.

Eighteen men and seven women with a mean age of 52 years (range, 20–65 years) received reirradiation during the given period. Median Karnofsky Performance Score (KPS) was 70% (range, 40–90). Twelve patients underwent surgery before reirradiation, while 13 patients were deemed inoperable and direct taken for reirradiation. The reirradiation methods included stereotactic radiosurgery (2), hypofractionated stereotactic radiation therapy (15–40 Gy in 3–5 fractions; 14 patients), or conventionally fractionated stereotactic radiation therapy (45–54 Gy in 25–27 fractions; 9 patients). Patients who received conventional fractionated radiation also received concurrent temozolomide at 75 mg/m². All patients completed the planned course of radiation therapy and also received adjuvant temozolomide. MGMT methylation status was available for 15 patients; 7 had MGMT methylated while 8 had non-methylated tumors.

Median follow-up from recurrence was 12 months (range, 1–47.8 months). Median overall survival (OS) from recurrence was 15.2 months (95% confidence interval [CI], 10–20.33 months). None of the factors analyzed (age, sex, gross tumor volume at time of recurrence, KPS, MGMT, time of recurrence) were significant for outcomes. No grade 3 or above acute or late complications were noted following reirradiation.

Our results suggest that reirradiation with high precision radiotherapy along with temozolomide is an effective option in patients with recurrent glioblastoma.