Rekürren Glial Tümörlerde Fraksiyone Stereotaktik Radyoterapi Radyocerrahi ile İkinci Seri Işınlama Sonuçlarımız

Abstract

Glial tumors are the most frequently diagnosed primary brain tumors and reccurence is inevitable despite definive primary treatment. Recurrence mostly occurs in the primary high dose radiotherapy area which makes reirradiation a challenge. In this prospective study we evaulated treatment outcomes of 31 recurrent glial tumor patients who were reirradiated with an image-guided stereotactic radiotherapy/ radiosurgery (SRC/fSRC) technique between December of 2012 and December of 2013. The median time between primary radiotherapy and reirradiation was 26 months ( 4-232 months). After the first radiation treatment 27 (%87) patients relapsed in the primary radiotherapy region. A median total dose of 30 Gy (18-40 Gy) was delivered in median fractions of 5 (1-5 fraction) with CyberKnife® (Accuray Incorporated, Sunnyvale, CA, USA). Median tumor volume was 13 cc (6-100 cc). The median overall survival after reirradiation was 15 months ( 6-33 months). Median survival after reirradiation was 11 months for patients with glioblastom, 30 months for patients with grade 3 tumors (p:0.04). At the end of multi-variate analysis only tumor volume (≥15 ml vs < 15 ml) was significant in influencing survival after reirradiation (p:0.015). Median follow up was 12 months (6-37 months). According to the radiologic findings at last examination 3 patients had regression, 6 patients had stable disease; 17 patients had progressive disease and 4 patients had grad 4 radionecrosis. The distinction between radionecrosis and progression was not clear in 1 patient who died 12 months after fSRC treatment following sudden deterioration in his general condition. This patient was considered to develop radionecrosis based on radiologic and clinical findings. Among patients who developed progression; 8 had in-field, 3 had in/out field, 3 had in-field progression and potential radionecrosis, 2 had leptomeningeal metastasis and 1 developed gliomatosis cerebri like disease. All the patients who developed grade 4 radionecrosis had tumor volumes greater than 25 cc. Large irradiation volumes increase radionecrosis risk and decrease tumor control probability. Stereotactic radiotherapy/radiosurgery is a safe and may be an effective treatment option for selected recurrent high-grade glioma patients with focal small tumor volumes.