Focal Management of Large Brain Metastases and Risk of Leptomeningeal Disease

BackgroundSurgery is often utilized for large or symptomatic brain metastases but is associated with risk of developing leptomeningeal dissemination. Emerging data suggests that fractionated stereotactic radiation therapy (FSRT) is an effective management strategy in large brain metastases. We sought to retrospectively compare leptomeningeal disease (LMD) and local control (LC) rates for patients treated with surgical resection followed by radiosurgery (S+SRS) vs. FSRT alone.Materials/MethodsWe identified all patients with a brain metastasis ≥3 cm in diameter treated from 2004-2017 with S+SRS or FSRT alone (25 or 30 Gy in 5 fractions) who had follow-up imaging. LMD was defined as focal or diffuse leptomeningeal enhancement that was >5 mm from the index metastasis. Categorical baseline characteristics were compared with the Chi-square test. LMD and LC rates were evaluated by the Kaplan-Meier (KM) method with the log-rank test utilized to compare subgroups.ResultsA total of 125 patients were identified, including 82 and 43 in the S+SRS and FSRT alone groups, respectively. Median pretreatment Graded Prognostic Assessment (GPA) in the S+SRS and FSRT groups was 2.5 and 1.5, respectively (p