SURVIVAL BENEFIT OF STEREOTAXIC RADIOSURGERY FOR PATIENTS WITH MALIGNANT GLIAL NEOPLASMS

OBJECTIVE: During an 8-year interval, we evaluated the survival benefi t of stereotactic radiosurgery performed in 65 patients with glioblast omas multiforme (GBM) and 43 patients with anaplastic astrocytomas (AA ). METHODS: Adjuvant radiosurgery was performed either before disease progression or for recurrent tumor at the time of disease progression. Clinical and imaging follow-up data were obtained for ail patients. T he diagnosis of GBM was obtained by performing craniotomies in 41 pati ents and by performing stereotactic biopsies in 23. The diagnosis of A A was obtained by performing craniotomies in 19 patients (44%) and by performing biopsies in 24. RESULTS: Of the entire series, the median s urvival time after initial diagnosis for patients with GBM was 26 mont hs (standard deviation [SD], 19 mo; range, 5-79 mo) and the median sur vival time after radiosurgery was 16 months (SD, 16 mo; range, 1-74 mo ). The 2-year survival rate was 51%. No survival benefit was identifie d for patients who underwent intravenously administered chemotherapy i n addition to radiosurgery (P = 0.97). After undergoing radiosurgery, 12 patients (19%) underwent craniotomies and resections and 4 (6%) und erwent subsequent radiosurgery for regional or remote recurrence. For 45 patients who underwent radiosurgery as part of the initial manageme nt plan, the median survival time after diagnosis was 20 months. Of th e entire series, the median survival time after diagnosis for patients with anaplastic astrocytomas was 32 months (SD, 23 mo; range 5-96 mo) and the median survival time after radiosurgery was 21 months (SD, 18 mo; range 3-93 mo). The 2-year survival rate was 67%. Ten patients (2 3%) underwent subsequent craniotomies at a mean of 8 months after init ial surgery, and two underwent, subsequent radiosurgery. There was no acute neurological morbidity after radiosurgery. Histologically proven radiation necrosis occurred in one patient with GBM (1.6%) and two pa tients with AA (4.7%). For 21 patients for whom radiosurgery was part of the initial management plan, the median survival time after diagnos is was 56 months. CONCLUSION: In comparison to historical controls, im proved survival benefit after radiosurgery was identified for patients with GBM and patients with AA. Although this survival benefit may be related to our selection of patients for radiosurgery based on their h aving smaller tumor volumes, no selection was made based on location. We observed that radiosurgery was safe and well tolerated. Its effecti veness as an adjuvant therapy deserves a properly stratified randomize d trial.