Temporal trends in the incidence and prognosis of lung metastasis in gallbladder cancer: risk stratification and survival analysis.

Lung metastases are the second most common visceral metastatic site in gallbladder cancer (GBC); however, population-based evidence regarding this metastatic pattern remains limited. In this study, we sought to define the incidence trend of lung metastasis in GBC, identify risk factors associated with its occurrence, and comprehensively assess survival outcomes in this patient population. Data on GBC patients diagnosed 2010-2022 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Joinpoint regression was used to evaluate temporal trends. Multivariate logistic regression was performed to identify independent risk factors. Overall survival (OS) was analyzed via Kaplan-Meier, multivariate Cox regression, and propensity score matching (PSM). The incidence of lung metastasis in GBC patients showed a modest but statistically significant increasing trend from 2010 to 2022, with an average annual percent change of 3.6% (95% CI 1.4%-5.8%, P<0.05). Independent risk factors for lung metastasis included advanced N stage (N1 and N2) and synchronous bone, liver, or brain metastases. GBC patients with lung metastasis exhibited poor prognosis, with a median OS of 5.0 months (95% CI 4.0-6.0). The 1-, 2-, and 3-year OS rates were 18.1%, 4.3%, and 1.0%, respectively. Isolated lung metastasis conferred better survival than concurrent other distant metastases (median OS: 7.0 vs. 4.0 months, P<0.001). Chemotherapy significantly improved survival (HR=0.39, 95% CI 0.32-0.49), whereas primary tumor resection showed no benefit after PSM. Survival rates in this population did not change significantly between 2010 and 2022. In conclusion, this comprehensive, population-based analysis provides contemporary insights into the epidemiology and management of this challenging patient population.