Prognostic impact of preoperative skeletal muscle change from diagnosis to surgery in patients with perihilar cholangiocarcinoma

BACKGROUND: Loss of skeletal muscle mass is a prognostic factor after surgery for gastrointestinal cancers. The treatment for perihilar cholangiocarcinoma (PHC) is a highly invasive surgery. Biliary drainage and portal vein embolization, which can prolong the preoperative waiting time (PWT), are often required before surgery. Assuming that the skeletal muscle mass can change during PWT, we investigated the clinical effect of skeletal muscle change on surgical outcomes of PHC. METHODS: We retrospectively reviewed the medical records of 89 patients who underwent curative surgery for PHC from January 2013 to December 2019. We defined the psoas muscle area (PMA) at the third lumbar vertebra as the skeletal muscle mass. The PMA just before surgery was divided by that at the time of diagnosis, and we defined it as the rate of change of PMA (CPMA). Patients were divided into two groups according to CPMA: wasting (n = 44, below the median CPMA) and no‐change (n = 45, above the median CPMA). RESULTS: The median PWT was 63 d, and CPMA was 96.1%. The median recurrence‐free survival and overall survival were significantly shorter in the wasting group than in the no‐change group (8.0 vs 33.2 mo, P = 0.001 and 14.2 vs 48.7 mo, P < 0.001, respectively). Multivariate analysis revealed that histological differentiation, R1 resection, lymph node metastasis, and preoperative skeletal muscle wasting were independent prognostic factors of PHC. CONCLUSION: This study suggests that preoperative skeletal muscle wasting in patients with PHC has a negative effect on survival outcomes.