RADIOGRAPHIC FINDINGS AND MORBIDITY IN PATIENTS TREATED WITH STEREOTACTIC RADIOSURGERY

Purpose: To determine the prognostic significance of pretreatment edem a, lesion size and location on morbidity following stereotactic radios urgery (SRS), Methods and Materials: Forty-seven evaluable patients wi th 63 lesions were treated on a 6-MV linear accelerator radiosurgery s ystem at Memorial Sloan Kettering Cancer Center, All patients received 10-mg intravenous bolus of dexamethasone sodium phosphate (Decadron) prior to SRS, Thirteen patients were treated for asymptomatic lesions while 34 were treated because of neurologic symptoms, The median dose delivered was 1800 cGy and the median prescription isodose curve was 8 5%. Pretreatment edema was measured on a transaxial T2-weighted MR ima ge acquired within 1 month of the SRS, Results: Ten patients experienc ed morbidity as a result of their treatment, The complication rate was measured by neurologic events following SRS and was not significantly influenced by the extent of peritumoral edema. Lesion size was also u nrelated to the development of post-treatment symptoms as assessed by the ease of tapering steroids. The only parameter found to influence p ost-SRS complications was lesion location, Four of six (66%) patients treated to lesions in the motor cortex suffered post-SRS seizure activ ity, whereas only 6 of 37 (16%) patients treated to lesions elsewhere in the brain parenchyma experienced seizure activity. Conclusion: The presence of pretreatment edema and lesion size are not predictors of p ost-SRS complication rates or the ability to taper Decadron, Lesion lo cation is predictive of post-SRS seizure activity. (C) 1998 Elsevier S cience Inc.