Implication of Skeletal Muscle Loss in the Prognosis of Patients with Pancreatic Ductal Adenocarcinoma Receiving Chemotherapy

OBJECTIVE: The effect of sarcopenia on the prognosis of patients undergoing chemotherapy for unresectable pancreatic ductal adenocarcinoma remains largely unexplored. In this retrospective study, we investigated the relationship between sarcopenia and the prognosis of patients receiving first-line nanoparticle albumin-bound paclitaxel plus gemcitabine for unresectable pancreatic ductal adenocarcinoma. METHODS: We enrolled 251 patients with unresectable metastatic or locally advanced pancreatic ductal adenocarcinoma who had received chemotherapy between January 2015 and December 2020 at Kitasato University Hospital. Univariate and multivariate analyses were performed using the stratified Cox proportional hazards model to determine variables significantly associated with the progression-free and overall survival. Propensity score matching was performed to mitigate selection bias effects. RESULTS: In the propensity score-matched cohort, the progression-free and overall survival were not significantly different between the sarcopenia and non-sarcopenia groups (p=0.335, and 0.679 respectively). The skeletal muscle index decreased by 4.4% and 6.5% in the sarcopenia and non-sarcopenia groups, respectively, during the early treatment phase (p=0.084). There were no significant differences between groups with regard to major adverse events or drug toxicity occurrences. Both the progression-free and overall survival were significantly shorter in the skeletal muscle index loss group than in the non-skeletal muscle index loss group (p=0.026 and 0.045, respectively). CONCLUSION: Skeletal muscle index loss during the initial treatment phase may be an early marker for the long-term prognosis of patients receiving nanoparticle albumin-bound paclitaxel plus gemcitabine as first-line treatment for unresectable pancreatic ductal adenocarcinoma.