Too Many Tumors Still Diagnosed After They Have Spread
Each year in California, about 25,000 women are diagnosed with breast cancer. These women are more likely to survive if their disease is caught when the tumor is still small and has not yet spread. When breast cancer is detected and treated before it has had a chance to spread, 95 percent of the women who have it are still alive after ten years. When the cancer is detected and treated after it has spread to other parts of the body, only 16 percent of the women survive ten years.
Current methods for figuring out the stage of a breast tumor are not perfect. Some tumors spread faster than others. In some cases, a tumor can be very tiny, and be diagnosed as being at an early stage, indicating that the woman's chance of survival is good. In reality, however, undetectable cells may have already spread to other parts of her body, lowering her chance of survival.
In California, more and more women are being diagnosed with small tumors that have no signs of having spread. However, this is not necessarily a sign of progress against the disease. An increase in the number of women diagnosed when their tumors are at more curable stages is only good news if there is also a decrease in the number of women whose cancer is diagnosed after their tumors have spread, when survival is less likely.
However, California has made only slight progress in reducing the number of women whose tumors are diagnosed after they have spread.
This means it is likely that screening large numbers of women with mammograms is leading to many women being treated for tumors that would never have caused them any trouble. These women are receiving treatments that cause discomfort and stress, and that may also later affect their health.
The chart below shows changes between the years 1988 and 1999.
Late-Stage Diagnosis among California Ethnic Groups
Asian/Pacific Islander Women
Asian/Pacific Islander women are the least likely to get breast cancer among California ethnic groups. However, their rates for the more dangerous breast cancers—those that have spread—which were already low in 1988, did not drop between that year and 1999. For all other ethnic groups, the rates for these types of tumors fell during those years.
African American Women
African American women have the highest rate of any California ethnic group for being diagnosed at the more dangerous stages, where the tumor has already spread. However, between 1988 and 1999, the rate at which African American women were diagnosed at the most dangerous stage, where the tumor has spread to other locations in the body, dropped by almost half.
The rate at which Hispanic women are diagnosed at a dangerous, late stage of breast cancer was lower than that of white or African American women in 1988. It also dropped a little between 1988 and 1999.
White women in California are more likely to be diagnosed with breast cancer than any other ethnic group. They also have high rates for being diagnosed with tumors that have already spread, and these rates dropped only slightly between 1988 and 1999.
Although the majority of cases of breast cancer are detected at an early stage, each year over 7,500 women in California are being diagnosed with breast cancer that has spread beyond its original site. Despite widespread use of mammograms to screen for the disease, the rate at which California women are diagnosed with late-stage breast cancer has barely changed. Improvements in detecting breast cancers that will spread before they have a chance to do so—including new technology and new methods such as blood tests—are still needed.
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 1988–1999. For more information on the Registry, and why the figures stop in 1999, see the introduction to this booklet. Information in this section comes from Chapter 8 of Breast Cancer in California, 2003, “Stage at Diagnosis of Female Breast Cancer California, 1988–1999,” by Paul K. Mills, Ph.D., M.P.H., and Ratnali Jain, M.B.B.S., M.S.