신장암 뇌전이에 대한 감마나이프방사선수술의 치료 결과

Abstract

Objective: Renal cell carcinoma (RCC) is a rare tumor which tends to metastasize to the brain in about 4-11% of patients. Metastases from RCC raise specific therapeutic problems because they are relatively unresponsive to whole brain radiation therapy and tend to bleed. The aim of this study was to analyze the therapeutic effects after Gamma Knife radiosurgery (GKS) as a primary treatment for patients harboring brain metastases of RCC. Methods: Between May 1992 and September 2005, 26 patients with 102 brain metastases from RCC underwent 31 GKS procedures. Overall median survival, main cause of death, local control rate, and morbidity related to GKS were evaluated. Age, sex, performance status, number of metastases, volume of metastases, presenting symptom, prior history of craniotomy, prior history of fractionated radiation therapy, prior history of chemotherapy or immunotherapy, maximal dose, tumor marginal dose, number of treatment isocenters, recursive partitioning analysis (RPA) class, and latency period from diagnosis of RCC to that of brain metastases were statistically analyzed to identify significant factors related to prolonged survival. Results: The mean tumor volume was 3.3 (0.02-35.1)cc. Mean maximal and tumor margin dose were 28.0 (15-43)Gy and 17.7 (9-26.6)Gy, respectively. The period of median survival was 10.5 months after GKS and RPA class was only significant factor related to survival. Local tumor control rate was 92.0% and tumor volume was related to local control. Radiation-related edema occurred in 8.9% of cases. Additional whole brain radiation therapy could not affect survival time, local tumor control, but could increase the risk of radiation-related complication. Local and distant tumor recurrences were treated by additional GKS. There was no permanent morbidity after GKS. Conclusion: Despite of the radioresistant nature of RCC, GKS alone could effectively control brain metastases from RCC not only as a primary treatment, but also as a secondary salvage for recurrence. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including repeated radiosurgery without a combination of whole brain radiation therapy can offer patients an extended survival.