Trends in Incidence and Prognostic Factors of Two Subtypes of Primary Liver Cancers: A Surveillance, Epidemiology, and End Results-Based Population Study

OBJECTIVES: The objective of our study was to investigate and compare the epidemiologic characteristics, prognostic factors, and survival between hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) patients. METHODS: Age-adjusted incidence rates were evaluated from 1975 to 2016 using the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) was investigated using the Kaplan–Meier method and log-rank test. Univariate and multivariate Cox regression analyses were performed to identify the independent prognostic factors for OS. RESULTS: In the last 10 years, the incidence rate of ICC increased rapidly by 109% (annual percentage change (APC) = 8.24, 95% CI = 6.64 to 9.86; P < .001), compared with a much more modest 12% increase in the incidence of HCC (APC = 1.59, 95% CI = .56 to 2.62; P < .001). This trend persisted throughout the study across different age groups, sexes, and races. Males older than 70 years and of other races (non-African American and non-Caucasian) showed the highest incidence rates of HCC and ICC. Multivariate Cox regression analysis demonstrated that other race, married status, later year of diagnosis, more examined lymph nodes, and surgery were significant protective factors of OS in HCC patients. In contrast, the race and year of diagnosis were not independent prognostic factors, but radiation and chemotherapy were protective factors of OS in ICC patients. The median OS was 18 months and 12 months in HCC and ICC patients, respectively. CONCLUSION: In the last 10 years, the incidence of HCC had a slow growth in the United States, whereas ICC showed a remarkable increase. The 5-year OS of the former has improved in recent years while that of the latter showed no significant improvement. Therefore, surgery could contribute to superior survival outcomes as compared to other treatments.