Abstract
OBJECTIVE: Studies on lung metastases from extrahepatic cholangiocarcinoma (ECC) are rare. This study aims to fill this gap by analyzing the influencing factors, prognosis, and chemotherapeutic efficacy of ECC lung metastases, and to provide insights for optimizing medical care for patients with ECC lung metastases. METHODS: We retrieved data from the Surveillance, Epidemiology and End Results (SEER) database for patients with metastatic ECC (stage M1) from 2018 to 2021. The study analyzed these characteristics using descriptive statistics. To calculate Hazard Ratios (HR), multivariate COX regression analyses were performed. Overall survival (OS) was estimated using the Kaplan-Meier method, and the survival of patients between groups was compared using the log-rank test. RESULTS: A total of 762 people participated in the study, 50.4% of whom were men. At the time of diagnosis, 17.8% of patients had pulmonary metastases. 52.5% received chemotherapy. Multivariate COX analysis identified lung metastases as a significant risk factor for death from metastatic ECC (HR 1.64, CI 1.32-2.03, p < 0.001). Treatment with chemotherapy (HR 0.20, CI 0.17-0.25, p < 0.001) and female sex (HR 0.80, CI 0.67-0.94, p = 0.008) were associated with a better prognosis. Therefore, we further compared the prognosis and chemotherapy outcomes of male and female patients with ECC lung metastases. The median survival of male patients with and without lung metastases was 2 and 5 months, respectively (p = 0.016), whereas there was no significant difference in female patients (p = 0.19). Regardless of gender, patients with lung metastases had significantly worse OS even after receiving chemotherapy (p = 0.0065 in the male group and p = 0.0075 in the female group). Regardless of gender, patients with lung metastases who did not receive chemotherapy had significantly shorter overall survival than those who received chemotherapy. Not receiving chemotherapy vs. receiving chemotherapy (male: 1 month vs. 5 months, p < 0.0001; female: 2 months vs. 9 months, p < 0.0001). CONCLUSION: Pulmonary metastasis is an important prognostic factor in ECC and is associated with poorer survival, especially in male patients. Therefore, preventive measures and effective control of lung metastases (e.g., chemotherapy), especially in male patients, may improve survival in patients with ECC.