The Asian-American and Pacific Islander population, including Vietnamese, Korean, Chinese, Filipino, and Japanese ethnicities, is among the most rapidly expanding heterogeneous groups in the United States. Perhaps not surprisingly, epidemiologic data show some striking differences in disease and mortality rates among these ethnicities compared with non–Asian-American populations. For example, the annual incidence of cancer-related mortalities among Asian Americans and Pacific Islanders is higher than that for heart disease, the only ethnic groups in the United States for which this is the case.1 Further, there is a higher incidence of cancers among Asian Americans and Pacific Islanders not typically seen in the Westernized countries.
A recent paper by McCracken et al evaluated national data sets associated with the leading types of cancers in the Asian and Pacific Islander populations, specifically those who live in California, and found liver, lung, and cervical carcinomas to be among the leading types.2 The researchers found both the highest incidence and mortality rates of all three cancers among Vietnamese Americans living in California.2 Potential reasons for the high incidence and mortality rates in these populations differ and include recent immigration from geographic regions associated with higher rates of infectious diseases not commonly seen in the West. We focus here on the incidence and mortality of liver cancer, as it relates to the Asian-American and Pacific Islander populations living in the United States, and California specifically.
- Liver cancer incidence in California is highest in Vietnamese men (54.3/100,000, eight times higher than non-Hispanic whites), followed by Koreans and Chinese.
- HBV is the major cause of liver cancer in most Asians.
- Lower screening rates were seen in recent immigrants with poorer English proficiency, socioeconomic status, and education.
Hepatocellular carcinoma (HCC) is very high among Asians in general, and among the Vietnamese, Koreans, and Chinese in particular.3 The increased prevalence of liver cancer is believed to be associated with the higher rate of chronic hepatitis B virus (HBV) infection seen in Vietnam, Korea, and China. HBV infection is more prevalent in the developing world, Asia, and Sub-Saharan Africa, and is the main cause of liver cancer in those areas.4 Of note, 55% of the worldwide incidence of liver cancer occurs in China.4
While no national database currently exists to track the incidence, mortality, and risk factors for cancers among Asian Americans and Pacific Islanders ethnicities in the United States, data on incidence and mortality are available from both the Surveillance, Epidemiology, and End Results (SEER) regions, including California and Hawaii, and the California Cancer Registry (CCR). Data on risk factors and screening behaviors are available from the California Health Interview Survey (CHIS). Of note, approximately 3.7 million Asian Americans, or 12% of the total Asian-American population, resides in California.
In looking at the data from SEER (1988–1992) and CCR (2000–2002), McCracken et al found the incidence of liver cancer among Vietnamese men residing in California to be 54.3 per 100,000 with a mortality rate of 35.5 per 100,000. (See Table).2 The incidence and mortality rates among Vietnamese women were 15.8 and 10.4 per 100,000, respectively, second only to the incidence and mortality rates seen in Korean women, which were 15.9 and 11.5 per 100,000, respectively. Korean men who reside in California had the second highest incidence and mortality rates of liver cancer: 33.7 and 26.6 per 100,000, respectively.2
The incidence of liver cancer and related mortality among Chinese men living in California were 23.3 and 19.9 per 100,000, respectively. Among Chinese women, the incidence and mortality rates were 7.6 and 7.8 per 100,000, respectively.2 (See Table).
Age-Adjusted Liver Cancer Rates (per 100,000) by Asian American Ethnic Group, California, 2000-2002, California Cancer Registry2
* The two highest rates for each gender-specific cancer site among the Asian ethnic groups.
While screening with serum AFP and liver ultrasound every 6 months can detect liver cancer at an earlier and more treatable stage, screening rates for liver cancer are low among some Asian populations5, and particularly among those with recent immigration histories. Limited language abilities, specifically English proficiency, lower socioeconomic status and educational levels, as well as cultural factors all represent potential barriers to healthcare and low screening rates.2 For example, sociodemographic data from the US Census Bureau from 2000, broken down by ethnic group, show that Vietnamese living in California have the lowest levels of education and income of the Asian ethnicities living in that state, and the second lowest rates of health insurance: as the earlier data showed, Vietnamese-American males have the highest incidence of HCC and associated mortality among Asian-American ethnicities.2
Of all the factors that contribute to low screening rates, insufficient English likely represents a more broadly applicable barrier to healthcare and may be the most easily overcome. Of note, the Asian American Network for Cancer Awareness Research and Training, which is funded by the National Cancer Institute and the American Cancer Society, have developed a searchable Web portal for cancer materials for the general public available in 12 Asian languages.
HBV vaccination, hepatitis B-immune globulin administration, and antiviral treatment should be used to reduce the spread of HBV, particularly among people at high risk, such as those with cirrhosis or neonates born to HBV-infected mothers.6
Given that the Asian-American and Pacific Islander populations are among the fastest growing ethnic populations in the United States, and given that the incidence of HCC in these populations results in part from HBV infection more commonly seen in their countries of origin, improved screening and surveillance should be undertaken to reduce the incidence of HBV and subsequently the associated incidence and mortality rates of HCC.
- National Center for Health Statistics. Health United States, 2006 with Chartbook on Trends in the Health of Americans. Hyattsville, MD: National Center for Health Statistics. Available at: http://www.cdc.gov/nchs/hus.htm. Accessed September 14, 2007.
- McCracken M, Olsen M, Chen MS, et al. Cancer incidence, mortality and associated risk factors among Asian Americans of Chinese, Filipino, Vietnamese, Korean, and Japanese ethnicities. CA: A Cancer J Clin. 2007;57:190-205.
- American Cancer Society. Cancer Facts & Figures 2005. Atlanta, GA: American Cancer Society 2005. Available at: http://www.cancer.org/docroot/STT/content/STT_1x_Cancer_Facts__Figures_2005.asp. Accessed September 14, 2007.
- Stewart BW, Kleihues P. World Cancer Report. Lyon, France: IARC Press; 2003.
- Zhang BH, Yang BH, Tang ZY. J Cancer Res Clin Oncol. 2004;130:417-22.
- Gish RG. Improving outcomes for patients with chronic hepatitis B. Curr Gastroenterol Rep. 2007;9:14-22.