P13.08 * CAN HYPOFRACTIONATED STEREOTACTIC RE-IRRADIATION IMPROVES THE OUTCOME IN PATIENTS WITH RECURRENT GLIOBLASTOMA?

Abstract

BACKGROUND: Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Tumor control and survival have improved with the use of radiotherapy (RT) plus concomitant and adjuvant TMZ, but the prognosis remain poor. In most cases the recurrence occurs within 7-9 months after primary treatment and up to 90% in close proximity to the resection cavity or the target volume of postoperative RT. Currently, many approaches are available for the salvage treatment of patients with recurrent GBM, including resection, re-irrradiation or systemic agents, but no standard of care exists. MATERIALS AND METHODS: This is a retrospective analysis of 91 consecutive patients with GBM treated between 2007 and 2012 with conventional adjuvant chemo-radiation therapy. The pattern of recurrence and salvage therapy (re-operation, re-irradiation, chemotherapy or supportive care), evaluated by interdisciplinary neuro-oncology team, was analyzed for all patients. The salvage radiotherapy was performed with hypo fractionated stereotactic technique with a total dose of 25 Gy in 5 consecutive fractions. RESULTS: At the time of data analysis, 74 out 91 patients had died and the tumour progression was the primary cause of death in 65 patients. Among 17 patients still alive, 11 were in stable disease and 6 in course of systemic salvage therapy. Recurrence occurred “in-field” in 59 patients (80%), and “out-field” in 14 patients (20%). At the time of recurrence, re-operation was performed in 6 patients, chemotherapy in 37 patients, best supportive care in 13 patients and salvage RT was in 15 patients. The median time interval between primary RT and salvage RT was 10.8 months (range, 6-54 months). The median overall survival was 17 months, 16.8 months, 9.9 months and 33 months for patients treated with re-surgery, chemotherapy, best supportive care and re-irradiation, respectively. In salvage RT patients, KPS (p = 0.03) and O6-methylguanine-DNA-methyltransferase (MGMT) methylation status (p= 0.02) were statistically correlated with OS. No patients demonstrated clinically significant acute morbidity, and all patients were able to complete the prescribed radiation dose without interruption. Neurological deterioration occurred in two patients at 1 and 3 months after re-irradiation and was managed successfully with dexamethasone. CONCLUSION: The current literature suggests that hypo-fractionated stereotactic radiation therapy is effective and safe in recurrent GBM after conventional chemo-radiation treatment. Until prospective randomized trials consolidate these results, the decisions for salvage treatment will remain individual and should be based on multidisciplinary analysis of each patient.