A recent press release reports that the Mayo Clinic Cancer Center in Rochester, Minn., recently completed a research study that found women with at least three sites of cellular atypia (abnormality of a cell) in breast tissue are nearly eight times more likely than average women to develop breast cancer. The findings are published in the July 1 issue of the Journal of Clinical Oncology.
The press release says that a number of prior studies have also shown that atypia in breast tissue is a major breast cancer risk, and women who have been diagnosed with atypia after a breast biopsy are considered a high risk. But until this recent study, questions remained on whether a positive family history further increases risk in women with atypia and for how long the increased risk in women with atypia lasts.
Dr. Amy Degnim is a Mayo Clinic surgeon and one of the study’s authors. The press release quotes her as saying, “The most commonly used tool for risk prediction in women with atypia is the Gail model, which may predict inaccurately because our study shows that family history does not change risk significantly in women with atypia. Our findings indicate that women with atypia have a higher absolute risk for breast cancer than previously estimated. This risk is 25 percent over 25 years and is much higher in women with multiple areas of atypia and calcification.”
The Gail model predicts risk by using age at onset of menses, age at birth of first child, number of previous breast biopsies, presence of atypia, and number of close relatives with breast cancer.
While the Mayo Clinic study found that family history did not further increase risk, age at diagnosis of atypia did affect risk, with younger women (under age 45) more than twice as likely to develop breast cancer compared to women diagnosed with atypia after 55.
The press release says the number of areas of cellular atypia was significant too. With one area of atypia, breast cancer risk was 2.3-fold compared to the general population; this risk more than doubled when two sites were found, and increased to nearly 8-fold as sites increased to three or more. The group of women with the highest risk had three or more areas of atypia and calcification — with a 10.4-fold risk over the general population.
“With the ability to stratify the risk of breast cancer in women with atypia, we can have more informed discussions with our patients regarding their personal risk,” says Dr. Degnim in the press release. “This will help us to have individualized discussions regarding how aggressively to pursue risk-reduction treatments.”
The source of the findings was from the records of 331 women with atypia identified within the Mayo cohort of 9,376 women who had benign breast biopsies surgically obtained between 1967 and 1991. The press release says that more than half (55.9 percent) of the women were over age 55 when diagnosed with atypia, and 42.9 percent had a family history of breast cancer. The majority (68.6 percent) of women showed calcification in the biopsy tissue, and 40 percent had multiple sites of atypical hyperplasia.
The press release says that the American Cancer Society reports that more than 240,000 women will be diagnosed in the United States this year with breast cancer, and more than 40,000 will die from it. Dr. Degnim and her fellow researchers have been working to better understand the steps that precede breast cancer and which of them can be recognized in benign breast tissue. The current study contributes to Mayo’s emerging model that seeks to define every woman’s risk more precisely and to tailor screening and risk-reduction measures to women depending on their individual risks.
The press release says that the Mayo Clinic research project was supported in part by a Department of Defense Center of Excellence Grant, the Susan G. Komen Breast Cancer Foundation, the Breast Cancer Research Foundation, and the Fred C. and Katherine B. Andersen Foundation.
Mayo Clinic, Mayo Clinic-led Study Improves Breast Cancer Risk Prediction in Women with Atypia; http://www.mayoclinic.org/news2007-rst/4117.html