Combined impact of myosteatosis and liver steatosis on prognosis in stage I-III colorectal cancer patients.

Abstract

Myosteatosis and liver steatosis (LS) have been recognized as patient-derived image biomarkers that correlate with prognosis in colorectal cancer (CRC) patients. However, the significance of considering fat deposition in multiple body areas simultaneously has been underestimated. This study aimed to investigate the combined effect of myosteatosis and LS in stage I-III CRC patients. A total of 616 stage I-III CRC patients were included in the study. Myosteatosis was assessed using skeletal muscle radiodensity (SMD), and LS was estimated by calculating the Hounsfield unit of the liver and spleen ratio (LSR). Cox proportional hazard models were utilized to evaluate disease-free survival (DFS). A combination of myosteatosis and LS was proposed, and its discriminatory performance was compared using the C-index. Among the 616 participants, the median (interquartile) age was 64 (55-72) years, and 240 (38.9%) were female. The median and interquartile range of LSR were determined as 1.106 (0.967-1.225). The optimal cutoff value for LSR was identified as 1.181, leading to the classification of patients into low (410, 66.5%) and high LSR (206, 33.4%) groups. Among the patients, 200 were categorized into the low SMD group, while 416 were allocated to the high SMD group. Both myosteatosis and LS were identified as independent prognostic factors in the multivariable analysis. The combination of these two variables resulted in a three-group classification: high SMD with low LSR group, high SMD with high LSR group, and low SMD group. When comparing the C-index values, the three-group classification exhibited superior discriminatory performance compared with considering myosteatosis and LS separately. Myosteatosis was associated with poorer survival, while the presence of LS was linked to a better prognosis in non-metastatic CRC patients. Simultaneously considering fat infiltration can serve as a more effective prognosticator in non-metastatic CRC patients.