Incidence, risk factors, and prognosis in patients with primary hepatocellular carcinoma and lung metastasis: a population-based study

Aims: The study aims to explore the incidence, risk factors, and prognosis in patients with primary hepatocellular carcinoma (HCC) and synchronous lung metastasis using a large-scale population-based cancer registry database. Patients and methods: Data of 33,177 HCC patients were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. Multivariate logistic and Cox regression model analysis were applied for the recognition of risk factors and prognostic factors associated with lung metastasis among HCC patients. The overall survival and cancer-specific survival of HCC patients with initial pulmonary metastasis were estimated by Kaplan-Meier analysis, and the survival curves were compared by log-rank tests. Results: Total 2,084 (6.28%) HCC patients diagnosed with initial pulmonary metastasis were enrolled for analysis. Male gender, younger age, non-white race, unmarried status, uninsured status, elevated alpha-fetoprotein, larger primary liver tumor size, positive lymph node status, synchronal bone or brain metastasis, and tumor poor pathological differentiation were relevant to higher risk of lung metastasis in HCC cohort. The 1-, 3-, 5-year overall survival and cancer-specific survival rates for HCC lung metastasis patients were 12.8% vs 15.3%, 4.0% vs 5.7%, and 1.6% versus 2.4%, respectively. The median overall and cancer-specific survival time in HCC lung metastasis group were both 3 months, while the corresponding time in HCC lung metastasis-free group were 19 and 25 months (P<0.05). Older age, unmarried status, poor tumor differential grade, and absence of surgery were identified as unfavorable prognosis factors. Conclusion: The survival of patients with HCC lung metastasis was dismal. Several clinicopathological factors were found to be significantly relevant to the development and prognosis of HCC lung metastasis. These new findings could be useful for a precise and individualized therapeutic schedule.