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Cancer affects Asian Americans in different ways than it does other racial and ethnic groups in the US. A new American Cancer Society report provides details of cancer patterns in this population -- and shows great variations based on country of origin.

The report, published in the ACS journal CA: A Cancer Journal for Clinicians, is one of the most thorough evaluations of cancer in Asian Americans, according to the researchers. The authors say it can be used to help tailor cancer prevention and early detection strategies for various Asian groups in the US.

Overall, Asian Americans have the lowest cancer incidence and death rates when compared to non-Hispanic whites, African Americans, and Hispanics in the US. However, cancer is the leading cause of death among Asian Americans, with heart disease being first among the other groups.

To better understand how cancer affects people of Asian descent living in the US, the researchers used data from California. That state has the greatest number of Asian Americans living in it -- about 3.7 million -- and uses a detailed breakdown of Asian ethnicity when collecting population information. The researchers examined cancer trends in the 5 largest Asian-American groups: Chinese, Filipino, Vietnamese, Korean, and Japanese.

Colorectal cancer rates are higher among Chinese Americans than most other Asian groups, the report says, approaching that of non-Hispanic whites. While the risk for this type of cancer is low in China, it is higher among Chinese who have been in the US longer, hinting that adopting a Western lifestyle may play a role.

Chinese Americans are more likely than other Asian groups to be screened for colorectal cancer. Still, only about 40% of men and 42% of women report having a colonoscopy in the past 5 years.

Liver cancer also takes a high toll among Chinese-American men. This cancer is also very common in China itself, and may be caused in part by high rates of infection with the hepatitis B virus in that country.

Lung cancer rates are high among Chinese-American women, the report says, which is surprising because comparatively few Chinese-American women smoke. However, many are exposed to secondhand smoke at home and at work, as well as to smoke from high-temperature frying.

Prostate cancer is the most commonly diagnosed cancer among Asian-American men of all ethnicities, and Filipino men have the highest incidence and death rates from this cancer of all Asian-American groups.

Lung cancer is also a problem among Filipino men. They have the second-highest incidence rate and the highest death rate from this disease.

Filipino women have the highest breast cancer death rate and the second-highest breast cancer incidence rate of Asian-American women. One factor that may contribute to this is the percentage of overweight women in the Filipino community, which is the highest of all the ethnic groups studied. Being overweight or obese is a well-established risk factor for breast cancer after menopause.

Vietnamese men have the highest incidence and death rates of liver cancer of all Asian-American groups studied. Liver cancer is very common in Vietnam, where chronic infection with the hepatitis B virus is widespread. Because many Vietnamese in the US are recent immigrants, they may be more likely to have this risk factor for liver cancer, the report says.

Vietnamese women have the highest incidence and death rates for cervical cancer of all Asian groups studied. Screening for cervical cancer with a Pap test is less common among Vietnamese women than it is among several other Asian groups. About 70% reported getting a Pap test within the past 3 years.

Lung cancer is more common among Vietnamese men and women than it is among the other Asian groups included in the report. Stomach cancer is also common among both men and women of Vietnamese descent.

Stomach cancer is much more common among people of Korean ancestry than other Asian groups, and death rates from this disease are highest among Koreans. The typical Korean diet, which includes many foods that are high in salt and nitrates/nitrites, may be part of the reason stomach cancer rates are so high.

Koreans also have the highest rates of liver cancer among women and the second highest rate among men. This is likely caused by the high prevalence of hepatitis B virus infection in the Korean population, the report says.

Korean women have the lowest screening rate for cervical cancer, and the second highest incidence and death rate from that disease.

Colorectal cancer screening rates are also low among Korean Americans; Korean-American men have the second-highest colorectal cancer incidence and death rates.

Lung cancer is not as common among Korean men as it is among some other Asian men, but Korean men have the highest death rate from the disease.

Japanese men and women have the highest rate of colorectal cancers and deaths of all Asian groups. One reason may be that the Japanese are more likely to be overweight than members of most other Asian groups, and being overweight raises a person's risk of developing colorectal cancer. In addition, a large percentage of Japanese men do not meet physical activity guidelines, another factor that can raise colon cancer risk.

Japanese women have the highest incidence of breast cancer among the Asian Americans included in the report. However, Japanese women also have the highest breast cancer screening rates, which may mean cancers are simply more likely to be detected in Japanese women than other groups.

Stomach cancer also takes a large toll in the Japanese community. A diet high in salt and nitrates/nitrites may be partly responsible.

Language barriers are one of the problems facing many Asian Americans dealing with cancer, particularly those who came to the US recently. The report highlights some resources to help overcome these obstacles.

ACS has worked with the Asian American Network for Cancer Awareness, Research and Training (AANCART) to develop a searchable Web site with materials on cancer prevention and early detection in more than 12 Asian and Pacific Islander languages.

The report also urges doctors to familiarize themselves with the cancers that are more common in Asian populations than in other US ethnic/racial groups.

Citation: " Cancer Incidence, Mortality, and Associated Risk Factors Among Asian Americans of Chinese, Filipino, Vietnamese, Korean, and Japanese Ethnicities." Published in the July/August 2007 CA: A Cancer Journal for Clinicians (Vol. 57, No. 4: 190-205). First author: Melissa McCracken, MPH, American Cancer Society.