Effect of preoperative body composition on long-term outcomes in patients undergoing distal cholangiocarcinoma resection

Differences in preoperative body composition are associated with the prognosis of patients with a variety of cancers. The aim of this study was to investigate the effect of preoperative body composition on the prognosis of radically resected distal cholangiocarcinoma patients. A total of 110 patients with pathologically diagnosed distal cholangiocarcinoma who underwent radical surgery from January 2017 to September 2022 were retrospectively analysed. Body composition indices, such as the skeletal muscle index (SMI), subcutaneous fat area (SFA), visceral fat area, and skeletal muscle radiodensity, were measured at the level of the third lumbar vertebra using a segmentation tool (TOMOVISION-sliceOmatic), and the correlation of clinicopathologic variables, including body composition indices, with overall survival (OS) and disease-free survival (DFS) was assessed. In addition, based on the presence of sarcopenia (low SMI) and subcutaneous tissue obesity (high SFA), we assigned the patients to three groups and performed a joint-effects group prognostic analysis. Of the 110 patients included, 18 (16.4%) had preoperative sarcopenia, and 58 (52.7%) had subcutaneous tissue obesity. A total of 56 patients (50.9%) died during the follow-up period, with a median survival of 19 months (IQR: 13.00–32.00). Sarcopenia and low SFA were significantly associated with mortality. Multivariate Cox regression showed that preoperative sarcopenia (HR = 3.13, 95% CI = 1.53–6.10, P = 0.002) and low SFA (HR = 1.92, 95% CI = 1.08–3.45, P = 0.026) were independent predictors of poor OS, and preoperative sarcopenia (HR = 3.23, 95% CI = 1.63–6.11, p < 0.001) and low SFA (HR = 2.01, 95% CI = 1.13–3.47, P = 0.018) were also independent predictors of poor DFS. According to the results of the joint-effects analysis, patients in the SN group (sarcopenia nonobese group) were associated with poorer OS and DFS ( p < 0.001). Our study revealed that preoperative sarcopenia and a low SFA were independent predictors of worsening OS and DFS in radically resected distal cholangiocarcinoma patients. Regarding fat depots, subcutaneous adipose tissue seems to have more prognostic value than visceral fat.