At issue is the National Cancer Institute's online risk calculator. Answer a few questions -- such as current age, age when your first child was born, family history of breast cancer -- and learn your odds of getting breast cancer in the next five years.
But the calculator has a caveat: It was created using studies of breast cancer in white women. A warning flashes telling non-white women that the answer they're about to get comes with some uncertainty.
Now scientists are updating the calculations to reflect newer data on black women and cancer.
It turns out the original calculator had been slightly underestimating risk for black women 45 and older, and slightly overestimating risk for younger black women, NCI researchers reported Tuesday in the Journal of the National Cancer Institute.
Dr. Mitchell Gail and colleagues reexamined the records of 20,000 black women who were screened for a government study comparing cancer-protective drugs. To qualify, women had to have at least a 1.66 percent risk of breast cancer in the next five years.
Using the old calculator, these women's average risk was 1.19 percent. Using the new one, their average risk was 1.75 percent, a small difference.
But overall, just 14 percent of these women qualified for the study using the old risk calculator. Had the new one been in use, 30 percent would have qualified, an important difference, Gail concluded.
The NCI will have its online risk calculator -- at http://www.cancer.gov/bcrisktool/ -- updated with the new statistics for black women by spring, Gail said.