USC researchers highlight disparities in cancer rates among racial and ethnic groups in California

USC epidemiologists have just spelled out the disparities along race and ethinic lines for cancer incidence and mortality here in California. It’s sort of a work-plan for us for the next decade. I suspect similar disparities exist all across the country. See the last paragraph.

LOS ANGELES (Dec. 14, 2004) – Among Californians, black men face the highest risk of being diagnosed with cancer, and their rates are almost three times as high as those among South Asian groups, according to statistics from the California Cancer Registry and researchers at the Los Angeles Cancer Surveillance Program at USC/Norris Comprehensive Cancer Center.

Cancer incidence and mortality rates differ so much among California ethnic groups that black men are actually five times more likely to die of cancer than are South Asian men, for example. Yet rates of certain cancers (such as liver and stomach cancer) are much higher among Koreans and Chinese than among blacks and other groups.

These findings are just a small part of the newly released report "Cancer Incidence and Mortality in California: Trends by Race and Ethnicity 1988-2001," an examination of 14 years of statewide cancer data. The Los Angeles Cancer Surveillance Program, or CSP, produced the report with data from fellow regional cancer registries. About 140,000 cancer cases and 50,000 cancer deaths are reported statewide each year.

The report is the first statewide study of cancer incidence rates in ethnic communities that are seldom examined, such as South Asians (Asian Indian, Bangladeshi, Pakistani and Sri Lankan) and Vietnamese. It also highlights cancer in changing populations, such as Latinos. Such studies contribute to a better understanding of cancer.

By gender, the report shows that black men and non-Latino white women are hardest-hit, proportionately, by cancer. But cancer rates vary significantly by gender and ethnicity: For 19 different kinds of cancer, one ethnic or racial group had at least three times greater incidence of that cancer than another ethnic or racial group.

"Identifying differences and trends in cancer rates by race/ethnicity is the key to identifying how successful our cancer control efforts are, and tells us a lot about the causes of cancer, and how to prevent it," says Myles Cockburn, Ph.D., assistant professor of preventive medicine at the Keck School of Medicine of USC.

A sampling of trends includes the following:

  • Prostate cancer was the most common cancer among men of all racial or ethnic groups except Koreans, for whom stomach cancer was most common, and Vietnamese, among whom lung cancer was most common.

  • Prostate cancer death rates were ten times higher in blacks than in Asian groups.

  • Breast cancer was the most common women’s cancer among all groups except Koreans, in whom lung cancer was most common.

  • Breast cancer incidence rates increased rapidly for all groups except Latinas, among whom incidence rates declined. In situ breast cancers increased rapidly among all groups, indicating far-reaching effects of mammography screening.

  • Cervical cancer rates declined among all racial and ethnic groups, presumably due to screening, but the decline was small in Koreans and Filipinas, possibly due to limited access to screening. Declining cervical cancer mortality rates for all groups suggest that screening is saving women’s lives.

  • Esophageal cancer declined rapidly in blacks but was steady or increased slightly in Asian groups. This reflects the existence of two types of esophageal cancer: one related to smoking and the other unrelated to it.

  • Melanoma rates among non-Latino whites increased so rapidly that melanoma now ranks in the top five cancers for men and women. Increased screening may contribute to the rising trend.

  • Lung cancer death rates increased among women of all races and ethnicities.

  • Thyroid cancer rates increased steadily among most racial and ethnic groups.

  • Colorectal cancer rates, traditionally lower among Filipinos and Koreans, are increasing among these groups, as well as among other Asians.

    Because California is home to a wide array of ethnic groups-both immigrant and native-born-it represents a unique opportunity to understand cancer among different communities. In the future, the diversity seen in California is likely to be seen nationwide.

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