Supplementary Material for: Low Skeletal Muscle Density Is Associated with Early Death in Patients with Perihilar Cholangiocarcinoma Regardless of Subsequent Treatment

Background: Low skeletal muscle mass is associated with increased postoperative morbidity and worse survival following resection for perihilar cholangiocarcinoma (PHC). We investigated the predictive value of skeletal muscle mass and density for overall survival (OS) of all patients with suspected PHC, regardless of treatment. Methods: Baseline characteristics and parameters regarding disease and treatment were collected from all patients with PHC from 2002 to 2014. Skeletal muscle mass and density were measured at the level of the third lumbar vertebra on CT. The association between skeletal muscle mass and density with OS was investigated using the Kaplan-Meier method and Cox survival. Results: Median OS in 233 included patients did not differ between those with and without low skeletal muscle mass (p = 0.203), whereas a significantly different median OS (months) was observed between patients with low (HR 7.0, 95% CI 4.7–9.3) and high (HR 12.1, 95% CI 8.1–16.1) skeletal muscle density (p = 0.004). Low skeletal muscle density was independently associated with decreased OS (HR 1.78, 95% CI 1.03–3.07, p = 0.040) within the first 6 months but not after 6 months (HR 0.68, 95% CI 0.44–1.07, p = 0.093), after adjusting for age, tumour size and suspected peritoneal or other distant metastases on imaging. Conclusion: A time-dependent effect of skeletal muscle density on OS was found in patients with PHC, regardless of subsequent treatment. Low skeletal muscle density may identify patients at risk for early death.

研究背景：肝门部胆管癌（perihilar cholangiocarcinoma, PHC）患者接受根治性切除术后，骨骼肌质量低下与术后并发症发生率升高及生存期缩短密切相关。本研究旨在探讨骨骼肌质量与密度对疑似PHC患者总生存期（overall survival, OS）的预测价值，且不局限于后续治疗方案。研究方法：本研究纳入2002年至2014年间确诊的所有PHC患者，收集其基线特征、疾病相关参数及治疗相关数据。通过计算机断层扫描（CT）在第三腰椎层面测量患者的骨骼肌质量与密度。采用Kaplan-Meier法与Cox生存分析，探讨骨骼肌质量、密度与患者总生存期之间的关联。研究结果：本研究共纳入233例患者，伴与不伴骨骼肌质量低下的患者其中位总生存期无显著差异（p=0.203）；而骨骼肌密度低下与高密度患者的中位总生存期（月）存在显著差异（p=0.004）：前者风险比（hazard ratio, HR）为7.0，95%置信区间（confidence interval, CI）为4.7~9.3，后者HR为12.1，95%CI为8.1~16.1。在校正年龄、肿瘤大小及影像学提示的疑似腹膜或其他远处转移因素后，骨骼肌密度低下与患者前6个月内的总生存期缩短独立相关（HR=1.78，95%CI=1.03~3.07，p=0.040），但6个月后则无此关联（HR=0.68，95%CI=0.44~1.07，p=0.093）。研究结论：本研究发现，无论后续治疗方案如何，PHC患者的骨骼肌密度对总生存期存在时间依赖性影响。骨骼肌密度低下可用于识别早期死亡风险较高的患者。