Sarcopenia predicts an adverse prognosis in patients with combined hepatocellular carcinoma and cholangiocarcinoma after surgery

Background The prognostic value of sarcopenia in combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) patients after surgery has not been evaluated, while the efficacy of the available tumor stage for cHCC-CC remains controversial. Methods All consecutive cHCC-CC patients after surgery were retrieved. The patients were stratified by the sex-specific medians of the psoas muscle index into groups with or without sarcopenia. Prognosis was analyzed using the Kaplan-Meier (K-M) method, and the K-M curves were adjusted by inverse probability weighting (IPW). A nomogram based on Cox regression analysis was established and further compared with primary liver cancer (PLC) stages by internal validation based on bootstrap resampling and k-fold cross-validation. Results A total of 153 patients were stratified into sarcopenia and non-sarcopenia groups. The sarcopenia group revealed statistically worse overall survival (OS) and disease-free survival (DFS) using the K-M method and K-M curves adjusted by IPW. Multivariate Cox regression analyses suggested sarcopenia as an independent risk factor for OS (HR = 1.55; p = 0.040) and DFS (HR = 1.55; p = 0.019). Subgroup analysis based on baseline variables showed sarcopenia as a stable risk factor for the prognosis. Our nomogram outperformed PLC stages in prognostic prediction, as evidenced by the best c-index, area under the curve, and positive improvement of the net reclassification index and integrated discrimination improvement. A fivefold cross-validation revealed consistent results. Decision curve analysis revealed higher net benefits of the nomogram than PLC stages. Conclusions Sarcopenia is an independent and stable risk factor for the prognosis of cHCC-CC patients after surgery. Our nomogram might aid high-risk patient identification and clinical decisions.