Striking Racial/Ethnic Disparities in Liver Cancer Incidence Rates and Temporal Trends in California, 1988-2012

Background: Hepatocellular carcinoma (HCC) is characterized by disparate risk patterns by race/ethnicity. We examined HCC incidence patterns and temporal trends among detailed racial/ethnic populations, including disaggregated Asian-American subgroups. Methods: Using data from the population-based California Cancer Registry, we identified 41 929 invasive HCC cases diagnosed during 1988-2012. Patients were grouped into mutually exclusive racial/ethnic groups of non-Hispanic (NH) white, NH black, Hispanic, and NH Asian/Pacific Islander (API), as well as Asian subgroups of Chinese, Filipino, Japanese, Korean, Vietnamese, Cambodian, Laotian, and South Asian. Age-adjusted and age-specific incidence rates by sex, race/ethnicity, and time period were calculated. The average annual percent change (AAPC) in incidence rates was estimated using joinpoint regression. All estimates were provided with the 95% confidence intervals (CIs). Results: Aggregated NH API had higher HCC risk than NH whites, NH blacks, and Hispanics. When disaggregated, Southeast Asians (Vietnamese, Cambodians, and Laotians) had overall HCC incidence rates eight to nine times higher than NH whites and more than twice that of other ethnic Asians. Statistically significant rising temporal trends of HCC were found in NH whites, NH blacks, and Hispanics, especially those older than age 50 years. Overall HCC risk declined in Chinese males (AAPC = -1.3%, 95% CI = -2.0 to -0.6), but rose in Filipino (AAPC = +1.2%, 95% CI = 0.3 to 2.1) and Japanese males (AAPC = +3.0%, 95% CI = 0.4 to 5.6) and Vietnamese (AAPC = +4.5%, 95% CI = 0.7 to 8.5) and Laotian (+3.4%, 95% CI = 0.1 to 6.8) females. Conclusions: Our findings provide valuable information for the identification of at-risk ethnic subgroups of Asian Americans while underscoring the importance of disaggregating ethnic populations in cancer research.