Study: Breast Cancer Risk Model Inaccurate for Blacks

The formula used for the National Cancer Institute's Breast Cancer Risk Assessment Tool, commonly known as the Gail model, often underestimates the risk of cancer in older black women, according to research published Tuesday on the Web site of the Journal of the National Cancer Institute, the Washington Post reports.

The original formula was based on data from about 240,000 white women. For the new research, lead author Mitchell Gail -- an NCI biostatistician who led development of the original model that bears his name -- and colleagues used data on more than 3,200 black women, including 1,600 who had breast cancer, to re-evaluate the Gail model and seek to develop a better formula for black women.

The researchers tested the newly developed model using data from the Women's Health Initiative and found it more accurately predicted black women's risk. Next, they compared the two formulas using data collected from more than 20,000 black women who were screened for eligibility to participate in the Study of Tamoxifen and Raloxifene trial, which compared the two cancer drugs (Stein, Washington Post, 11/28).

The analysis showed that the old Gail model slightly underestimated the risk for black women who were older than 45 and that it slightly overestimated risk for younger black women (USA Today, 11/28). Overall, the old model underestimated risk in at least 90% of all scenarios involving black women, especially among older women, the researchers found.

The updated model "could have broad implications for many black women, prompting them to reconsider the danger they face from a disease that is women's leading type of cancer and second-leading cancer killer," the Post reports.

According to the Post, "That could translate into more women undergoing mammograms and other examinations to detect the disease in its earliest, most treatable stages; taking drugs such as tamoxifen to reduce their risk; and signing up for studies to identify better warning signs or risk-reducing medicines" (Washington Post, 11/28).

The Chicago Tribune reports that black women "likely have been inadvertently excluded" from cancer studies because researchers have used the Gail model to determine who is at higher risk for the disease (Peres, Chicago Tribune, 11/28).

Gail and his team found that for the STAR trial, of the more than 20,000 black women screened for eligibility, only 14% qualified. They determined that had the updated model been used, 30% would have qualified for the trial (AP/Houston Chronicle, 11/27).

Gail said he plans to research new models for other groups including Hispanics and Asians (Washington Post, 11/28). NCI's Breast Cancer Risk Assessment Tool, which is publicly available online, will be updated using the new model in the spring (Chicago Tribune, 11/28).

NBC's "Nightly News" on Tuesday reported on the study. The segment includes comments from Funmi Olopade of the University of Chicago Medical Center, Lisa Newman of the University of Michigan and a breast cancer patient (Snyderman, "Nightly News," NBC, 11/27).

Video of the segment is available online.