Impact of precise quantitative assessment of visceral obesity on outcomes of patients with metastatic renal cell carcinoma treated with systemic therapy.
597 Background: With its excellent resolution of adipose tissue, CT presents precise quantitative assessment of visceral obesity. We assessed the impact of visceral obesity on progression free and overall survival in patients treated with systemic therapy for metastatic renal cell carcinoma. Methods: This retrospective cohort study included 114 patients treated with systemic therapy for metastatic renal cell carcinoma between 2007 and 2015 at Keio university hospital in Japan. The visceral fat area was measured at the level of umbilicus using CT. A visceral fat area ≥100cm2 was used as the definition of visceral obesity. Progression free and overall survival was compared according to visceral obesity. Results: In the whole cohort, the median progression free survival in first line treatment was 12.0 month. The median overall survival was 42.5 month. According to Memorial Sloan-Kettering Cancer Center classification, 31 patients were favorable risk, 61 were intermediate risk, and 22 were poor risk; median overall survival for these groups were 76.9, 40.8, and 23.7 months, respectively (P<0.0001). Visceral obesity correlated with improved progression free (P=0.0095) and overall survival (P=0.0002). On multivariate analysis, visceral obesity (HR 0.64, P=0.0393) and Memorial Sloan-Kettering Cancer Center classification (P=0.0037) were independent indices to predict progression free survival in first line treatment. In addition, visceral obesity (HR 0.42, P=0.0016) and Memorial Sloan-Kettering Cancer Center classification (P=0.0006) independently predicted overall survival. Conclusions: The precision of CT imaging for measuring visceral fat tissue provides useful clinical venue to predict prognosis for metastatic renal cell carcinoma. Visceral obesity may be a useful and independent indicator for a better prognosis in patients treated with systemic therapy for metastatic renal cell carcinoma.