RT-04 * STEREOTACTIC RADIOSURGERY (SRS) IN RECURRENT HIGH-GRADE GLIOMA

Abstract

Despite the failure of the RTOG 9305 randomized trial to demonstrate the efficacy of SRS in newly diagnosed glioblastoma, this treatment was reported in several institutional series to be modestly effective, particularly in the setting of limited focally recurrent disease. This is a retrospective review of 55 SRS treatments in 47 patients with recurrent high-grade glioma treated at our institution between 2004 to 2013. Thirty-two (63%) patients suffered from glioblastoma and 15 from high-grade glioma. The median age was 53.3 years (24-86). The initial non-surgical treatment included Stupp protocol in 35 (74.5%), adjuvant temozolamide after RT in 3, PCV or other chemotherapy in 4 patients and in 5 patients SRS was the only postoperative intervention. The indication for SRS was locally progressing lesions in 32 (68%) patients and a new distant lesion in 15 (32%). Eight (17%) patients received a second salvage SRS treatment for a new focus. None of the repeat SRS treated patients experienced treatment related toxicity. The median target volume was 2.1 cc (0.2-9.5cc) and the median prescription dose for LINAC-based SRS treatment was 18 Gy (14-24Gy). Median time to progression was 5.1 months (1.0-96.4). Longstanding responses (> 12 months) were observed in 8 (17%) patients. One patient developed clinically significant radiation necrosis 3 months after SRS and required a surgical resection, but remained asymptomatic and without radiological evidence of active disease for more than 51 months thereafter. One additional patient developed biopsy -proven RN, which was resolved conservatively. No other treatment associated side effects were observed. Median survival time after SRS was 15.5 months (0.2-109.3) and overall median survival (since diagnosis) was 39.0 months (10.7-193.6 months). In conclusion, SRS may be considered an effective salvage procedure in selected patients with recurrent high-grade gliomas, providing long term responses in almost 20% of the cases.