Abstract
BACKGROUND: Lung metastasis is the most common extrahepatic metastasis organ for intrahepatic cholangiocarcinoma (ICC), often leading to an unfavorable prognosis. Although nomograms exist for predicting the risk of distant metastasis in ICC patients, a precise prognostic model specifically for patients with established intrahepatic cholangiocarcinoma lung metastasis (ICCLM) remains lacking. The aim of this study was to develop and validate a prognostic nomogram for predicting cancer-specific survival (CSS) in patients with ICCLM based on the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: We extracted data on 620 patients with ICCLM from the SEER database spanning the years 2010 to 2020. Patients from 2010 to 2017 were randomly allocated to a training cohort (n=274) and an internal validation cohort (n=118). Data from 2018 to 2020 (n=228) served as the external validation cohort. Employing both univariate and multivariate Cox regression analyses, we identified independent prognostic factors for ICCLM and subsequently developed a nomogram for CSS prediction. The performance of the nomogram was then assessed using the C-index, calibration plot, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA). Kaplan-Meier (KM) survival curves were plotted to illustrate survival disparities across different risk strata. RESULTS: Based on these factors, a nomogram was constructed. In the training, internal validation, and external validation cohorts, the C-index of the nomogram was 0.723, 0.761, and 0.758, respectively. The calibration curve, ROC curve, and DCA demonstrated commendable performance in predicting the 3-, 6-, and 12-month CSS for ICCLM patients. The KM survival analysis indicated that the 1-, 3-, and 5-year CSS rates for ICCLM patients were 23.9%, 3.3%, and 0.8%, respectively, with a median CSS of 5 months. Notably, there was a significant survival disparity between the low- and high-risk groups (P<0.05). CONCLUSIONS: The constructed nomogram stands out as a potent, individualized prognostic tool for ICCLM patients, poised to guide clinicians in tailoring more strategic and efficacious therapeutic regimens.