Simple Model Predicts Breast Cancer Risk in Postmenopausal Women

A new, simple model for predicting breast cancer risk in postmenopausal women appears to be as accurate as more complex methods currently used to decide whether women would benefit from medication to reduce their risk of getting cancer, according to a recent study.

Using data from the Women's Health Initiative, a 15-year program involving 161,808 postmenopausal women and funded by the U.S. National Institutes of Health (NIH; Rockville, MD, USA), scientists found postmenopausal women were at an "increased risk” of developing breast cancer if they were 55 years of age or older and had either had a breast biopsy at any time, regardless of findings, or had a first-degree relative (mother, sister, or daughter) who had breast cancer diagnosed at any age.

"For the first time, a postmenopausal woman can use a simple model and determine by herself if she is at increased risk of getting breast cancer,” said Dr. Rowan Chlebowski, a lead investigator at the Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles (UCLA) Medical Center (LA BioMed; Torrance, CA, USA). "She could then raise this issue with her health care provider because interventions to reduce her risk of breast cancer are now available.”

Increased risk is defined as about a 2% risk of developing breast cancer over the next five years. The investigators sought a quicker and easier way to determine risk because those who are at increased risk may benefit from tamoxifen treatment to reduce their chances of getting breast cancer.

Prior to this study, most physicians relied on the "Gail Model” to determine risk. But it involves so many variables that a computer is needed to determine a woman's risk of breast cancer. As a result, it was not used widely. Surveys found very few primary care physicians had used the Gail Model for risk assessment in the past year. In a national survey, only 16% agreed that it is "easy to determine” who is eligible for breast cancer risk reduction strategies and only 25% had prescribed tamoxifen for risk reduction in the past year.

The Gail model underestimated five-year breast cancer incidence by almost 20%, but it performed better when predicting estrogen receptor-positive breast cancer than estrogen receptor-negative breast cancer. The simpler model that used only three factors for calculating risk--age, family history of breast cancer, and previous breast biopsy--was almost as accurate as the Gail model for predicting estrogen receptor-positive breast cancer.

The proposed model "would be more accessible for routine and rapid prescreening in the prevention or routine care setting,” the authors wrote in the article, which was published in the advance access online issue on November 13, 2007, of the Journal of the National Cancer Institute.


Related Links:
Los Angeles Biomedical Research Institute
National Institutes of Health