STEREOTAXIC RADIOSURGERY FOR RECURRENT MALIGNANT GLIOMAS

Purpose: To evaluate the role of stereotactic radiosurgery in the mana gement of recurrent malignant gliomos. Patients and Methods: We treate d 35 patients with large (median treatment volume, 28 cm(3)) recurrent tumors that had failed to respond to conventional treatment. Twenty-s ix patients (74%) had glioblastomas multiforme (GBM) and nine (26%) ha d anaplastic astrocytomas (AA). Results: The mean time from diagnosis to radiosurgery was 10 months (range, 1 to 36), from radiosurgery to d eath, 8.0 months (range, 1 to 23). Twenty-one GBM (81%) and six AA (67 %) patients have died. The actuarial survival time for all patients wa s 21 months from diagnosis and 8 months from radiosurgery. Twenty-two of 26 patients (85%) died of local or marginal failure, three (12%) of noncontiguous failure, and one (4%) of CSF dissemination. Age (P = .0 405) was associated with improved survival on multivariate analysis, a nd age (P = .0110) and Karnofsky performance status (KPS) (P = .0285) on univariate analysis. Histology, treatment volume, and treatment dos e were not significant variables by univariate analysis. Seven patient s required surgical resection for increasing mass effect a mean of 4.0 months after radiosurgery, for an actuarial reoperation rate of 31%. Surgery did not significantly influence survival. At surgery, four pat ients had recurrent tumor, two had radiation necrosis, and one had bot h tumor and necrosis. The actuarial necrosis rate was 14% and the path ologic findings could have been predicted by the integrated logistic f ormula for developing symptomatic brain injury. Conclusion: Stereotact ic radiosurgery appears to prolong survival for recurrent malignant gl iomas and has a lower reoperative rate for symptomatic necrosis than d oes brachytherapy. Patterns of failure ore similar for both of these t echniques.