Cohort Contributions to Race- and Gender-Specific Trends in the Incidence of Hepatocellular Carcinoma in the USA.

INTRODUCTION: Increasing incidence of lifelong obesity and associated nonalcoholic steatohepatitis in younger birth cohorts may have contributed to growing incidence of hepatocellular carcinoma (HCC) in the USA. Yet, the contribution of cohort effects to trends in HCC incidence is unclear.

METHODS: Using data from the Surveillance, Epidemiology, and End Results (SEER) program 1973-2013, race- and gender-specific trends in HCC incidence in the USA were decomposed using age-period-cohort (APC) modeling.

RESULTS: Among SEER registry sites included in the analysis, there were 25,532 cases of HCC diagnosed including 15,867 (62%) White males, 3541 (14%) Black males, 5009 (20%) White females, and 1115 (4%) Black females. HCC incidence increases across periods, especially among men. Underlying this increase, APC models found significant cohort effects among White men, White women, and Black men, with rapid growth in HCC risk among cohorts born after 1940. A similar cohort trend among Black women did not reach statistical significance when compared to an age-period model.

CONCLUSIONS: Cohort-specific trends have significantly contributed to increasing HCC incidence in recent decades. The rapid increase in HCC risk among younger cohorts suggests that the incidence of HCC will continue increasing in the near future.