Between 1988 and 2000, only 24 percent of cancers diagnosed in California's Hmong were detected at an early stage. Nasopharyngeal cancer was diagnosed early in only 3 percent of cases, stomach cancer in only 10 percent of cases and liver cancer in only 15 percent.
More than a third of the nation's 169,000 Hmong -- 65,000 -- live in California. The U.S. State Department last year granted permission for another 15,000 Hmong to enter the country from Thailand. About half of these newest immigrants are also expected to settle in California.
"The Hmong are a unique people with unique health challenges," says Moon S. Chen, Jr., professor of public health sciences at UC Davis School of Medicine and Medical Center. Chen is principal investigator of the Asian American Network for Cancer Awareness, Research and Training (AANCART), an $8.5 million project funded by the National Cancer Institute and headquartered at UC Davis.
"Until now we have had very little information about cancer rates and risks in the Hmong," Chen said. "This study points to the need for increased cancer education, awareness and screening among the Hmong both in California and nationally to help them confront cancer, one of their biggest health threats."
To determine cancer rates in the Hmong, researchers combed the California Cancer Registry for cancer cases diagnosed in individuals with one of the 18 Hmong surnames. Several of these surnames, including Yang and Lee, are common to people of both Hmong and Chinese heritage. To avoid misclassification, cases with surnames that could be either Chinese or Hmong were further examined for place of birth and surnames of next-of-kin.
Between 1988 and 2000, the researchers found 749 cases of cancer in California's Hmong. Overall, the age-adjusted cancer rate in the Hmong was 284 cases per 100,000, 22 percent lower than in Asian Americans overall in California and 44 percent lower than in the state's non-Hispanic white population.
But the overall low cancer rate in the Hmong -- reflecting the community's low incidence of colorectal, lung, breast and prostate cancers -- masks very high rates of other cancers. Nasopharyngeal cancer, for example, occurs at a rate of 16 cases per 100,000 people among Hmong males – 16 times the rate for non-Hispanic whites in California.
Nasopharyngeal cancer is associated with several risk factors, including consumption of Cantonese salted fish and infection with Epstein Barr virus. Liver cancer is associated with chronic infection with hepatitis B virus, and stomach cancer may be associated with the bacteria H. pylori and consumption of highly salted, smoked or pickled foods.
"With access to Western medicine, including hepatitis B immunization, antibiotics for bacterial infections and Pap screening, the rates of the cancers that are now most prevalent in the Hmong should decrease within a generation," said Richard Yang, research scientist at the Cancer Registry of Central California based in Fresno.
But without education, the Hmong may see their now-low rates of lung, colorectal, breast and prostate cancers begin to climb within a generation. "Smoking is not common in the Hmong," Yang said. "However, as younger Hmong become more Westernized, cigarette consumption and lung cancer may increase. In addition, if the Hmong follow the pattern seen in other Asian migrant groups, particularly the Japanese and Chinese, their rates of Western cancers like breast and colon cancer will also start to rise. We have a unique opportunity, with the Hmong, to prevent this pattern."
Through AANCART, UC Davis researchers have partnered with the Hmong Women's Heritage Association in Sacramento to raise cancer awareness and screening rates in the region's Hmong. The university and Hmong women's group have translated cancer information pamphlets into Hmong and developed and offered Cancer Awareness 101 and Cancer Awareness 201 courses to Hmong community leaders and medical interpreters. Every new Hmong family arriving in the Sacramento region has been offered a free health kit containing cancer screening and early detection information. In addition, AANCART-UC Davis has launched a patient "navigator" program in which a Hmong medical interpreter accompanies Hmong cancer patients to their medical appointments, helps them understand and follow treatment plans, and provides assistance as needed with insurance, transportation and other barriers.
AANCART-UC Davis has also compiled a Hmong-English cancer glossary. After lengthy community debate, consensus was reached on a Hmong word for cancer: kheesxawj.
The first Hmong arrived in the United States from Thai refugee camps in the early 1980s, settling primarily in California's Central Valley and the St. Paul, Minn., area. Among California's Hmong today, 44 percent have less than a ninth grade education and only 18 percent have a high school diploma or equivalent degree. Half of all Hmong families in the state live below the federal poverty level. More than 54 percent of Hmong families have seven or more members per household.
AANCART is the largest project ever undertaken to reduce cancer in Asian Americans. Based at UC Davis, it includes researchers from seven other institutions: Harvard, Columbia, the M.D. Anderson Cancer Center at the University of Texas, the University of Washington, UCLA, UC San Francisco and the University of Hawaii.
The 5th Asian Cancer Control Academy is sponsored by the National Cancer Institute; the U.S. Office of Minority Health, Region IX; AANCART; the California Department of Health Services; the American Cancer Society; and UC Davis.
Copies of all news releases from UC Davis Health System are available on the Web at http://news.ucdmc.ucdavis.edu