MLTI-09. UNDERWEIGHT AND WEIGHT LOSS ARE PREDICTORS OF POOR OUTCOME IN PATIENTS WITH BRAIN METASTASIS

BACKGROUND: Despite increased risk of comorbidities, overweight may be associated with improved outcome in patients with metastatic cancer. Conversely, tumor cachexia has been identified as a negative predictor of outcome in patients with brain metastasis (BM) from lung cancer. Here we evaluate the association of abnormal body mass index (BMI) and weight change with outcome in patients with BM from different primary tumors. METHODS: Patients with a diagnosis of BM diagnosed and treated at the University Hospital Zurich (n=703) were assessed for associations of BMI, weight change, comorbidities and survival. RESULTS: Compared with patients with normal BMI of 18.5–24.9 kg/m2 who experienced a median overall survival (OS) of 9 months (95% confidence interval (CI) 7.5–10.5), OS was inferior in patients with BMI< 18.5 kg/m2 (OS 6 months, 95% CI 1.6–10.3, p=0.04), but superior in patients with BMI >25 kg/m2 (OS 13 months, 95% CI 11.0–15.0; p=0.033). For patients with documented weight course (n=173 of 703), we report a median relative weight loss of 5% within the first 6 months of BM diagnosis (95% CI 3.3–6.5). Reduction above the median was associated with an unfavorable outcome in this subgroup (weight loss ≧5% 22.0 months, 95% CI 19.2–24.8; weight loss < 5% 14.0 months, 95% CI 11.9–16.). CONCLUSIONS: Despite being associated with a worse cardiovascular risk profile, high BMI is associated with preferable and underweight with poor outcome in BM patients. Conversely, weight loss above median may be a predictor of poor outcome. Future studies need to address the question whether vigorous treatment of tumor cachexia, e.g. by specific nutrition management, might improve outcome of BM patients. In contrast, regimens that are associated with weight loss such as ketogenic diet may be detrimental.