News — Overall rates of new cancer diagnoses have declined in each of six Asian groups in the Greater San Francisco Bay Area, researchers at the Northern California Cancer Center (NCCC) have found. At the same time, the researchers saw significant differences in cancer rates among the six groups studied, with up to tenfold differences in the rates of new cancer diagnoses.
The findings are included in a newly released NCCC special report, "Cancer Incidence Among Asians in the Greater Bay Area, 1990-2002," using data collected over the 13-year period from NCCC's Greater Bay Area Cancer Registry (GBACR). The report details patterns and rates of new cancer diagnoses for six of the largest Asian groups " Chinese, Filipino, Japanese, Korean, South Asian, and Vietnamese " from nine Bay Area counties: Alameda, Contra Costa, Marin, Monterey, San Benito, San Francisco, San Mateo, Santa Clara and Santa Cruz.
From 1990 through 2002, the Bay Area's Asian population experienced tremendous growth, increasing by nearly 70 percent. During that time, 39,168 new cancer cases were diagnosed among Asians, with 18,000 new cases in the most recent five-year period (1998 through 2002).
The decline in the overall rates of new cancer diagnoses among each of the six Asian groups " from 7 percent among Vietnamese males to 32 percent among Japanese males " parallels the decline seen in other racial/ethnic groups, as documented in the GBACR's annual incidence and mortality report released in February.
While overall rates of new cancer diagnoses declined for both men and women, the report documents important differences across the six Asian groups. For example, NCCC researchers found a tenfold difference in the rates of liver cancer across the groups, threefold differences in the rates of prostate and colorectal cancers, and a twofold difference for breast cancer. Rates of liver cancer, which are highest among Asians compared to other racial/ethnic groups, decreased over time in all of the Asian groups except Vietnamese women. Japanese and Filipinos had the highest rates of hormone-related cancers, including breast, prostate, ovarian and endometrial cancers, while Koreans had the lowest rates of these cancers.
Among men, the rate of new cancer diagnoses was highest among Vietnamese, followed closely by Filipinos, Chinese and Japanese, and it was lowest among South Asians. Among women, the rate of new cancer diagnoses was highest among Japanese, followed by Chinese, Vietnamese, and Filipinas, and it was lowest among Koreans.
The five most common cancers varied across the groups as well. From 1998 to 2002, prostate, lung or colorectal cancer ranked as the most commonly occurring cancers among men, comprising 40 percent to 50 percent of all new cancer diagnoses. Among women, breast cancer was the most commonly occurring cancer in all groups, accounting for 25 percent to 35 percent of all new cancer diagnoses. The second and third most common cancers among Asian women were either colorectal or lung cancer.
"Our report is the first to use high-quality data to document important differences in cancer trends among Asian groups in the Greater Bay Area," said NCCC Research Scientist Scarlett Lin Gomez, Ph.D. "This detailed analysis will enable us to target cancer control efforts to meet the unique needs of each group." Highlights of the special report include:
Breast cancerRates of invasive breast cancer " where the cancer has started to break through normal breast tissue barriers and invade surrounding areas " remained the same or continued to rise among Chinese, Koreans, South Asians and Vietnamese, while rates among Japanese and Filipinas peaked during 1994-1997 and declined thereafter. The highest rates of breast cancer were found among Japanese, and these were two times higher than Koreans, who had the lowest rates of breast cancer. The patterns for invasive cancer differed somewhat with those for in situ breast cancer " where the cancer is confined to the ducts or lobules and has not spread to the surrounding tissues in the breast or other parts of the body " for which rates were highest and increased steadily over time among Chinese, Japanese and Filipinas.
Cervical cancerRates generally declined over time, particularly among Vietnamese women, but remained highest among Vietnamese. Colorectal cancerRates declined over time in all groups except Korean and Vietnamese men and South Asian women. Rates varied threefold across the groups, being highest in Chinese and Japanese and lowest in South Asians.
Corpus uteri cancerRates of corpus uteri cancer " also referred to as endometrial cancer " were highest among Japanese and Filipinas, and changed very little over time among Chinese, Japanese and Filipinas. The rates were somewhat variable among Koreans, South Asians and Vietnamese due to small numbers.
LeukemiaRates in men were nearly double those for women but were similar across Asian groups. They remained fairly stable over the time period. Liver cancerRates were highest among Vietnamese; among men, Vietnamese had tenfold higher rates than South Asians, the group with the lowest rates. New diagnoses of liver cancer remained constant among the groups except for Vietnamese women, in whom rates doubled over this time period.
Lung cancerRates in men were two to three times higher than rates in women, partly because more Asian men than women smoke cigarettes. Among men, rates were highest among Chinese, Filipinos and Vietnamese, while among women, rates were highest among Chinese and Vietnamese. Rates declined over time or remained essentially unchanged in all groups.
Non-Hodgkin lymphomaRates in men were double those for women, but with similar numbers of new diagnoses across all groups except Koreans, in whom rates were slightly lower. In general, rates declined over time, except in Chinese women, for whom there was no change, and in Vietnamese women, for whom rates doubled.
Oral cavity and pharyngeal cancerThere were large variations in rates across groups, with the highest rates among Vietnamese and Chinese and the lowest among Koreans and South Asians. Over time, rates were relatively stable within most groups, but there was a substantial decline in the rate for Filipinas and a slight decline in the rate for Japanese women.
Ovarian cancerRates declined slightly over time in all groups except Koreans, in whom it remained essentially the same. In the latest time period (1998-2002), rates were very similar across all groups.
Prostate cancerThere was a threefold difference in rates across the Asian groups, with the highest rates among Filipinos and lowest among Koreans. Rates decreased over time in all groups except for Chinese and Vietnamese men.
Stomach cancerRates were highest among Koreans, followed by Japanese and Vietnamese, and were lowest among South Asians, who experienced a threefold decline from the earliest time period (1990-1993). Thyroid cancerRates in women were about three times higher than rates in men, and were highest in Filipinos and Vietnamese.
Copies of "Cancer Incidence Among Asians in the Greater Bay Area, 1990-2002" may be downloaded from NCCC's Web site: .
About the Northern California Cancer CenterThe Northern California Cancer Center (NCCC) is dedicated to preventing cancer through population-based research and community education. An independent organization, NCCC is an established, nationally recognized leader in understanding who gets cancer and why, and how to improve the quality of life for individuals living with cancer. In addition to its research and education programs, NCCC operates the nine-county Greater Bay Area Cancer Registry, the statewide Cancer Information Service Partnership Program, and Cancer Detection Programs: Every Woman Counts (1-800-511-2300). For more information, visit www.nccc.org.
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