The impact of osteosarcopenia in patients with unresectable or recurrent biliary tract cancer receiving palliative chemotherapy.

BACKGROUND: Osteosarcopenia is a newly described syndrome that has been reported to be associated with worse outcomes in various types of cancer. However, its impact on survival in biliary tract cancer remains unclear. This study evaluated the impact of osteosarcopenia on survival in patients with unresectable or recurrent biliary tract cancer. METHODS: A total of 306 patients with unresectable or recurrent biliary tract cancer who initiated chemotherapy at our institution between 2015 and 2021 were retrospectively investigated. Skeletal muscle index and bone mineral density were measured using pretreatment cross-sectional computed tomography images. Baseline characteristics and survival outcomes were compared between patients with osteosarcopenia and those without. The Cox proportional hazards regression model was used to identify factors associated with survival. RESULTS: Osteosarcopenia was present in 66 patients (22%) and was associated with older age (74 vs. 69 years, P < 0.001) and female sex (58 vs. 37%, P = 0.003). Patients with osteosarcopenia tended to have worse performance status (P = 0.098), higher modified Glasgow prognostic score (P = 0.082), higher neutrophil to lymphocyte ratio (P = 0.058) and were significantly less likely to receive combination chemotherapy (68 vs. 80%, P = 0.044) than those without. Osteosarcopenia was associated with reduced survival (8.9 vs. 14.0 months, P < 0.001) and was identified as an independent factor predicting shorter survival in multivariate analysis. CONCLUSIONS: Osteosarcopenia was associated with poor survival in unresectable or recurrent biliary tract cancer treated with chemotherapy. This study highlights the potential importance of screening for osteosarcopenia in patients with biliary tract cancer.