P17.16 Reirradiation of recurrent glioma.

Abstract

OBJECTIVE: To evaluate the impact of re-irradiation on performance status and survival in patients with recurrent glioma. METHOD: A retrospective analysis was performed on 14 patients who received re-irradiation for recurrent glioma from Dec 2013 to Feb 2015. The GTV was defined as the contrast-enhancing lesion on T1-weighted MRI. No CTV was defined. Median GTV-PTV margin was 1.25cm (range 0.7-2.1). All patients received VMAT, 2 non co-planar arcs. The dose delivered was 30Gy in 5 fractions. Performance status and corticosteroid dosages had been recorded prospectively for all patients. A cohort of 22 recurrent glioma patients were identified in the 5 months prior to Dec 2013. This group did not receive reirradiation. Overall survival from initial diagnosis was calculated using the Kaplan-Meier method using SPSS. RESULTS: REIRRRADIATION COHORT: Median age was 49 (range 22-59). At initial diagnosis, 5 patients had glioblastoma (GBM), 2 WHO grade II astrocytoma and 7 WHO Grade II oligodendroglioma. All low grade (LGG) patients had radiological evidence of transformation to higher grade. All patients initially had surgical debulking followed by radiation to a median dose of 60Gy (range 54Gy-60Gy). At time of re-irradiation, patients had a mean KPS of 70% (range 60-90) and had progressed through at least one line of chemotherapy. Re-irradiation volumes overlapped previously irradiated fields in 14 patients. 1 week post XRT median KPS was 70% (range 60-90). 1 month post XRT median KPS was 90% (range 70-90). Median dexamethasone dose prescribed was 2mg pre-XRT (range 0-12), 4mg 1 week post XRT (range 0-8) and 4 mg 1 month post XRT (range 0-10). All patients completed treatment and no severe acute or late complications were observed. Progression free survival from the time of irradiation was 4.2 months (range 1-7) for GBM, 6.1 months (range 1-8) for LGG. Median survival from date of reirradiation was 8 months for GBM (range 5-11) and 11 months for LGG (range 5-18). Median overall survival from date of diagnosis for GBM was 34 months (range 26-46), and 126 months (range 49-192) for LGG. As a comparison, a similar cohort of patients aged <65, KPS >70% who had progressed through at least one line of chemotherapy after primary radiotherapy were identified from July 2013-Dec 2013. 12 were GBM patients: median survival from date of 2nd line treatment was 11 months (4-29) and median overall survival was 31 months (14-46). 10 LGG patients were identified with a median survival from date of 2nd line treatment of 12 months and median overall survival was 61.5 months (19-101). CONCLUSION: Re-irradiation is a safe and feasible treatment for recurrent glioma and the majority of patients experienced an improvement in performance status after treatment. However in this small, retrospective study there was no signal that reirradiation was associated with improved survival when compared with similar cohorts managed without reirradiation..