Women with atypical hyperplasia (also known as atypia) are at higher risk of developing breast cancer in future than previously thought, according to a Mayo clinic study.
The study found that hundreds of women with these benign lesions indicate that their absolute risk of developing breast cancer grows by over 1 percent a year; and five years later, 7 percent of these women had developed the disease; while the number had increased to 13 percent after 10 years; and 30 percent women had breast cancer after 25 years. The Mato clinic findings have been validated by researchers at Vanderbilt University using biopsies from a separate cohort of women with atypia. Both studies revealed that at 25 years following biopsy, 25 to 30 percent of these women had developed breast cancer.
Researchers were also able to give an accurate estimate of risk by incorporating information from a patient's pathology specimen. They found that as the extent of atypical hyperplasia in a biopsy increased, as measured by the number of separate atypia lesions or foci, so did the woman's risk of developing breast cancer. For example, at 25 years post-biopsy, 47 percent women with three or more atypia lesions in the biopsy had developed breast cancer, compared to only 24 percent of women with one focus.
The study has been published in the Journal of Medicine.