Study's findings on breast density might complicate models for assessing breast cancer risk

Sep 11 2006

A study published in the Sept. 6 edition of the Journal of the National Cancer Institute that finds breast density might be a risk factor for breast cancer could make assessment methods "considerably more complicated," the Los Angeles Times reports (Healy, Los Angeles Times, 9/11).

For the study, William Barlow of Cancer Research and Biostatistics in Seattle and colleagues examined data from more than one million women who had undergone mammograms to assess the risk of breast cancer in women with dense breast tissue.

Within one year of a mammogram, 11,638 women were diagnosed with breast cancer, according to the study.

Researchers found, after adjusting for age, that the risk for breast cancer was nearly four times greater in women with high breast tissue density than in those with less dense breasts.

The researchers said that it is too soon to assess how the findings could affect breast cancer survival (Kaiser Daily Women's Health Policy Report, 9/7).

University of California-Los Angeles breast cancer specialist Patricia Ganz said that although scientists are beginning to determine how to best measure breast density, some physicians already are using the study's findings as "another piece of information that can be used in the counseling" of patients.

According to the Times, thousands of physicians and women since 1998 have used a list of seven questions available on the National Cancer Institute Web site called the "Gail Model" as a tool to assess breast cancer risk.

The model -- which is named after NCI head biostatistician Mitchell Gail -- asks a woman to provide her current age and race, how many of her direct relatives have had breast cancer, how many benign biopsies she has had, the ages at which she gave birth and the age at which she began menstruating.

The model provides women with a five-year and lifetime risk for developing breast cancer, but the model does not have a question about breast density.

Gail said that although it is "[t]echnologically ... feasible" for women to obtain their breast density, few physicians can provide a density test (Los Angeles Times, 9/11).