Characteristics of Women Who Survive Breast Cancer
One way to measure the harm breast cancer does, and the progress medicine makes against the disease, is to look at how long women survive after being diagnosed.
A person who survives five years after diagnosis with some types of cancer is likely to live out a normal lifespan. But this is not true with breast cancer. More than half the women whose breast cancer comes back have survived more than five years after their original diagnosis. While 10-year survival rates give a better measure of lifetime survival, breast cancer can recur at any time. Ultimately, what matters is bringing the death rate down.
Researchers have taken a detailed look at characteristics of women in five Bay Area counties who were diagnosed with breast cancer between 1988 and 1992. The researchers tracked who survived and who died until 2001. Women who died from causes other than breast cancer were taken out of the statistics. They were not counted, for this research, as either dying or surviving.
These figures for the five Bay Area counties do not necessarily reflect the picture for the entire state.
Here are some things the researchers found:
African American and Hispanic Women Have Lower Rates of Survival
Young Women Are Less Likely to Survive
Unlike many other types of cancer, breast cancer is more deadly when it strikes younger women.
Women Diagnosed at Early Stages Are More Likely to Survive
A woman whose breast cancer is detected before it has spread beyond its original location is more likely to survive than a woman whose cancer was detected at a later stage.
However, some women with breast cancer are not helped by current treatment methods. If their cancer is detected at an early stage, they will have a longer survival time after diagnosis, but their lives may not actually last any longer than they would have with a later diagnosis. A woman whose tumor is going to end her life by age 50, because no treatment will be effective, is not helped if her treatment begins at age 42 rather than at age 48. However, if she is diagnosed and begins treatment at age 42, she will be counted as having survived longer than five years. If she is diagnosed and begins treatment at age 48, she won't. For this reason, widespread detection of breast cancer at earlier stages can make survival figures look better than they actually are.
Hormone Receptors Make A Difference
Hormone receptors are proteins found in some breast tumors. Two types, estrogen receptors and progesterone receptors, allow the tumors to take in the hormones estrogen and progesterone. These hormones normally circulate in women's blood. Tumors that have these receptors need the hormones to live and grow.
If a woman's tumor is positive for hormone receptors, it improves her chance of surviving. After five years, 91 percent of women whose tumors test positive for hormone receptors are alive, compared with 80–81 percent of women whose tumors test negative for these receptors. After ten years, 84–85 percent of women whose tumors have hormone receptors are alive, compared to 75–76 percent of women whose tumors do not have these receptors.
There are two reasons for the difference in survival. First, tumors that do not contain hormone receptors are more likely to be able to spread to other parts of the body. Second, there are better treatments to reduce recurrence of receptor-positive tumors.
Income and Education Affect Survival
Women with higher incomes and more education, who are more likely to get breast cancer to begin with, are also more likely to survive breast cancer than women with lower incomes and less education. The main reason seems to be that these women get diagnosed at earlier stages of the disease. For more about this, see the section of this booklet, “Income, Education, and Breast Cancer.”
How This Research Was Done
Researchers used information about 9,765 women diagnosed with invasive breast cancer between 1988 and 1992 in Alameda, Contra Costa, Marin, San Francisco and San Mateo counties. The information was collected by the federal government's National Cancer Institute as part of its Surveillance, Epidemiology and End Results (SEER) program. Information in this section comes from Chapter 11 of Breast Cancer in California, 2003, “Breast Cancer Survival in the San Francisco Bay Area,” by Cynthia O'Malley, Ph.D. and Gem Le, M.S.