PURPOSE: This study aimed to explore survival outcomes and prognostic factors between intrahepatic and extrahepatic cholangiocarcinoma after surgical resection. METHODS: Patients diagnosed with primary intrahepatic or extrahepatic cholangiocarcinoma between 2010 and 2018 who underwent cancer-directed surgery were identified from the SEER database. A 1:1 Propensity Score Matching was performed. Survival outcomes were analyzed via Kaplan-Meier curves and Log-rank tests. Multivariable Cox proportional hazards regression models and Fine-Gray competing risk models were constructed. RESULTS: A total of 1,586 eligible patients were included. After matching, 478 patients (239 per group) were balanced. In the matched cohort, intrahepatic patients exhibited significantly superior Overall Survival (OS) compared to extrahepatic patients (median OS: 45 vs. 25 months; HR = 1.244, 95% CI: 1.001-1.545, P = 0.049). Conversely, a Fine-Gray competing risk analysis showed no significant difference in Cancer-Specific Survival (CSS) between the subtypes (SHR = 0.818, 95% CI: 0.641-1.043, P = 0.105). Independent risk factors for OS included advanced age, T3/T4 stage, N1/N2 stage, and tumor size ≥ 5 cm. Notably, the retrieval of 4 or more lymph nodes was associated with improved OS (HR = 0.630, 95% CI: 0.469-0.846, P = 0.002), though its association with CSS was not statistically significant in the competing risk model. CONCLUSIONS: Results from this PSM analysis suggest that intrahepatic location is associated with better OS compared to extrahepatic disease, but cancer-specific survival is similar between the subtypes after accounting for competing risks. This divergence implies that survival differences might be driven by competing risks, potentially distinct long-term surgical morbidities, rather than intrinsic biological lethality. Furthermore, adequate lymphadenectomy (≥ 4 nodes) correlated with improved overall survival and staging accuracy, highlighting its potential role as a surgical quality metric for both subtypes. CLINICAL TRIAL NUMBER: Not applicable.
Jize Tian (2026) studied this question.