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The risk of developing breast cancer may have been underestimated in African-American women, according to the results of
a recent study. The Breast Cancer Assessment Tool, also known as the Gail model, is frequently used
to estimate a woman's risk of breast cancer based upon several factors including family breast cancer
history and age at first childbirth. However, the original model was developed based on data from
white women, which researchers believe may differ from breast disease characteristics of African-American
women. Researchers have recently developed a new version of the model, called CARE, using data
from African-American women, which they believe more accurately predicts these women's risk of breast cancer.
Researchers from the National Cancer Institute worked with researchers from the Women's Contraceptive and
Reproductive Experiences (CARE) Study, the Women's Health Initiative, and the Study of Tamoxifen and
Raloxifene (STAR) trial to produce and test the new model. To develop a new model, researchers
analyzed data from 1,607 African-American women with invasive breast cancer and 1,637
African-American women of similar ages who did not have breast cancer. The factors used in the model were:
- age at first menstrual period
- number of first degree relatives (mother or sisters) who had breast cancer
- number of previous non-cancerous breast biopsies
Unlike in white women, a woman's age at the birth of her first child was not included in
the model because the researchers found that it did not improve prediction in African American women.
To test the accuracy of the model, researchers compared their data with data from the 14,059 African
American women aged 50 to 79 in the Women's Health Initiative (WHI) study who had no prior history of breast cancer.
The new model shows an increased risk of breast cancer among African-American women. For example, the old
model found that a 50-year-old black woman who started having her period at age 14, had her first
baby at age 32 and had a mother and sister who had breast cancer has a 1.53% risk of getting breast cancer
within five years. The new model found that the same woman's risk is actually 2.26%. In total, the
study found that old model determined that 14.5% of African-American women were candidates for the STAR
trial, while the new model found nearly double the percentage of women (over 33%) were actually eligible.
"[National Cancer Institute's] Breast Cancer Risk Assessment Tool has been widely used for counseling women
and determining eligibility for breast cancer prevention trials," said the Institute's Director
John E. Niederhuber, M.D. "The development of the CARE model highlights the need to develop
targeted tools to assess an individual woman's risk, and those tools must be based on
many factors that also assure that the tool can be used in a non-discriminatory manner."
The model could be an important medical advance for African-American women. Growing research shows that
African-American women are more likely to develop aggressive breast cancer and to die
from the disease. According to the American Cancer Society, more than 19,000 African American women
are diagnosed with breast cancer each year, and nearly 6,000 die from the disease. Using the
new model could influence prevention decisions among African-Americans, including participation
in breast cancer prevention clinical trials or more frequent screenings.
The researchers caution that the Breast Cancer Assessment Tool, including the new CARE model, should not
be used for all women, including women with a previous history of breast cancer. The tools also
tend to underestimate risk in women who have received radiation to the chest and in women
who are known to carry mutations associated with increased risk of breast cancer, such as mutations
in the BRCA1 and BRCA2 genes. The CARE model will be incorporated in the Breast Cancer Assessment
Tool on the National Cancer Institute's website (www.cancer.gov) in Spring 2008.
Additional Resources and References
- The November 27, 2007 National Cancer Institute news release, "More Accurate Method of Estimating Invasive
Breast Cancer Risk in African American Women Developed," was posted on the Institute's website at
www.cancer.gov
- The study, Projecting Individualized Absolute Invasive Breast Cancer Risk in African American Women," was
published in the Journal of the National Cancer Institute, Vol. 99, No. 23,
http://jnci.oxfordjournals.org/
- To learn more about risk factors for breast cancer, please visit
http://www.imaginis.com/breasthealth/bc_risks.asp
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