Skeletal muscle radiodensity and visceral adipose tissue index are associated with survival in renal cell cancer – A multicenter population-based cohort study

Summary Introduction Body composition has been associated with disease outcome in several cancer types. Results for localized and metastatic renal cell cancer (RCC) are limited and inconsistent. Our aim was to examine the association between body composition and survival in RCC. Methods We conducted a population-based historical cohort study including patients diagnosed with RCC from 2008-2012. Diagnostic Computed Tomography images at the third lumbar vertebra (L3) were assessed for skeletal muscle index (SMI), skeletal muscle density (SMD), visceral adipose tissue index (VATI) and subcutaneous adipose tissue index (SATI). Clinical data was retrieved from medical records. Multivariable Cox regressions with restricted cubic splines were used to determine hazard ratios (HRs) and 95% confidence intervals (95%CIs) for 10-unit increases in body composition features with overall survival (OS) and recurrence-free survival (RFS). Results We included 719 stage I-III (of whom 254 (35.3%) died and 148 (21.9%) experienced recurrence) and 320 stage IV RCC patients (of whom 298 (93.1%) died). Median follow-up was 6.35 years (interquartile range; 1.41–8.23). For stage I-III, higher SMD was associated with better OS (men: HR 0.86; 95% CI 0.68–1.08; women: HR 0.69; 95% CI 0.50–0.95). Lower compared to median VATI was associated with worse OS for both men (HR 1.38; 95%CI 1.05-1.83 for VATI=25) and women (HR 1.67; 95%CI 1.01-2.78 for VATI=20). For stage IV, higher SMD and higher VATI were associated with better OS among men (HR 0.74; 95% CI 0.59–0.94 and HR 0.93; 95% CI 0.88–0.99, respectively). Results for women were similar but non-significant. No statistically significant associations were found for SMI or SATI. Conclusion Higher SMD and higher VATI were marginally associated with better survival in RCC patients and might be useful for better prognostication. However, the added value to current prognostic scores needs to be investigated.