Repeated gamma knife surgery for multiple brain metastases from renal cell carcinoma

Abstract

The aim of this study was to evaluate the therapeutic profile of repeated gamma knife surgery (GKS) for renal cell carcinoma that has metastasized to the brain on multiple occasions. Data from this study were culled from a single institution and cover a 6-year period of outpatient radiosurgery. A standard protocol for indication, dose planning, and follow up was established. In cases of distant or local recurrences, radiosurgery was undertaken repeatedly (up to six times in one individual). Seventy-five patients harboring 350 cerebral metastases were treated. Relief from pretreatment neurological symptoms occurred in 72% of patients within a few days or a few weeks after the procedure. The actuarial local tumor control rate after the initial GKS was 95%. In patients free from relapse of intracranial metastases after repeated radiosurgery, long-term survival was 91% after 4 years; median survival was 11.1+/-3.2 months after radiosurgery and 4.5+/-1.1 years after diagnosis of the primary kidney cancer. Survival following radiosurgery was independent of patient age and sex, side of the renal cell carcinoma, pretreatment of the cerebrum by using radiotherapy or surgery, number of brain metastases and their synchronization with the primary renal cell carcinoma, and the frequency of radiosurgical procedures. In contrast, survival was dependent on the patient's clinical performance score and the extracranial tumor status. Tumor bleeding was observed in seven patients (9%) and late radiation toxicity (LRT) in 15 patients (20%). Treatment-related morbidity was moderate and mostly transient. Late radiation toxicity was encountered predominantly in long-term survivors. Outpatient repeated radiosurgery is an effective and only minimally invasive treatment for multiple brain metastases from renal cell cancer and is recommended as being the method of choice to control intracranial disease, especially in selected patients with limited extracranial disease. Physicians dealing with such patients should be aware of the characteristic aspects of LRT.