LAUSR

BACKGROUND Patient fitness is important for guiding treatment. Muscle mass, as a reflection thereof, can be objectively measured. However, the role of east-west differences remains unclear. Therefore, we compared the impact of muscle mass on clinical outcomes after liver resection for HCC in a Dutch (NL) and Japanese (JP) setting and evaluated the predictive performance of different cut-off values for sarcopenia. METHOD In this multicenter retrospective cohort study patients with hepatocellular carcinoma (HCC) undergoing liver resection were included. The skeletal muscle mass index (SMI) was determined on CT scans obtained within 3 months before surgery. The primary outcome measure was overall survival (OS). Secondary outcome measures were: 90-day mortality, severe complications, length of stay, and recurrence free survival. The predictive performance of several sarcopenia cut-off values was studied using the c-index and area under the curve. Interaction terms were used to study geographic effect modification of muscle mass. RESULTS Demographics differed between NL and JP. Gender, age, and body mass index were associated with SMI. Significant effect modification between NL and JP was found for BMI. The predictive performance of sarcopenia for both short- and long-term outcomes was higher in JP compared to NL (max c-index: 0.58 vs 0.55, respectively). However, differences between cut-off values were small. For the association between sarcopenia and OS, a strong association was found in JP (Hazard ratio (HR) 2.00 95%CI[1.230 ; 3.08], P=0.002), where this was not found in NL (0.76 [0.42 ; 1.36], P=0.351). The interaction term confirmed that this difference was significant (HR 0.37 95%CI[0.19 ; 0.73], P=0.005). CONCLUSIONS The impact of sarcopenia on survival differs between the east and west. Clinical trials and treatment guidelines using sarcopenia for risk stratification should be validated in race-dependent populations prior to clinical adoption.