“Tri-modality” Therapy for Large Brain Metastases

Abstract

Long-term local and in-brain control is poor following single modality treatment of large brain metastases. We reviewed whether a combination of surgery, tumor bed radiosurgery and whole-brain radiation therapy (WBRT) may lead to better CNS control in these cases. The charts of patients treated for single brain metastases from September 2005 to January 2012 were retrospectively reviewed. Cases were included if the size of the metastasis was greater than 2cm.Forty-one cases were identified. The median tumor size was 3.6cm (range, 2.3-7.5). All patients underwent microsurgical resection of their brain metastasis followed by WBRT and a 10 Gy radiosurgery boost to the surgical cavity. In 84% of cases, the WBRT schedule was 30 Gy in 10 fractions (range: 20 Gy in 5 to 37.5 Gy in 15). The radiosurgery was delivered using a variety of techniques, typically prescribed homogeneously (median prescription isodose - 82%) at a 2mm margin from the cavity. Non-small cell lung cancer was the diagnosis in 59%, breast in 17%. Median age was 59. The majority (65%) were in RTOG RPA Class II (10% Class I, 25% Class III). Average DS-GPA for the lung cancer patients was 2.67. Median overall survival was 17.6 months. The 5-year actuarial survival was 30.1%. Crude local control was 93%, 2-year actuarial local control was 84%. With a median follow-up of 22 months in living patients, the crude rate of new metastases (including leptomeningeal disease) was 15%. Three patients suffered symptomatic radiation necrosis. Tri-modality therapy with surgery, WBRT, and cavity radiosurgery appears safe and provided durable CNS control in a population where long-term survivors are common.