Breast Cancer Cases and Deaths in California


Breast cancer strikes more than 25,000 California women per year. Looking at the actual number of cases provides some information, but a more meaningful number is the rate per 100,000 women, because it allows better comparisons between groups and over time. White women have the highest rate, followed by African American women. Hispanic and Asian/Pacific Islander women have lower rates. Although the risk of getting breast cancer is higher for older women, 55 percent of all California women who get breast cancer are under age 65 when they are first diagnosed, and 10 percent are under age 50.

The graph below shows how California women's breast cancer rates rise steeply as the women get older, then start dropping slightly at approximately age 75. The graph also shows how breast cancer rates vary by ethnic group.

Figure 1


Breast cancer kills over 4,000 women per year in California. Although white women are more likely to get breast cancer, African American women have the highest death rate. This is especially true for African American women under age 50, who have a death rate double that of other women in the same age bracket. The groups who are least likely to get breast cancer, Hispanic and Asian/Pacific Islander women, also have the lowest death rates.

For every ethnic group, the death rate starts going up after age 50, and in general keeps rising.

Figure 2

Age-Adjusted Breast Cancer Rates

The figures in this section are adjusted for age. Adjusting for age allows the rates to reflect what they would be if all ethnic groups in California had the same age distribution. Older women are more likely to get breast cancer. Adjusting for age means that the differences between the ethnic groups are not due to one group containing more older women than another.

How This Research Was Done

Researchers used information collected by the California Cancer Registry for the years 1995–1999. For more information on the Registry, and on why the information stops in 1999, see the introduction to this booklet. Information in this section comes from Chapter 3 of Breast Cancer in California, 2003, “Demographic Aspects of Breast Cancer Incidence and Mortality in California, 1988–1999,” by Sharon L. Campleman, Ph.D., M.P.H., and Robyn L. Curtis, M.S.