Women with atypical hyperplasia of the breast have a higher risk of developing breast cancer than previously thought, a Mayo Clinic study has found. The authors note that measures to prevent the progression of atypical hyperplasia to cancer are available but underutilized. Results of the Mayo study, including work from colleagues at Vanderbilt University and the University of Virginia, appear in a special report on breast cancer published online on January 1, 2015 in the New England Journal of Medicine. Atypical hyperplasia of the breast is a precancerous condition found in about one-tenth of the over 1 million breast biopsies with benign findings performed annually in the United States. Viewed under a microscope, atypia contains breast cells that are beginning to grow out of control (hyperplasia) and cluster into abnormal patterns (atypical). Atypia lesions are considered benign, but by its risk and appearance and genetic changes, these lesions exhibit some of the early features of cancer. Data from hundreds of women with these benign lesions indicate that their absolute risk of developing breast cancer grows by over 1 percent a year. The study found that after five years, 7 percent of these women had developed the disease; after 10 years, that number had increased to 13 percent; and after 25 years, 30 percent had breast cancer. The finding places the more than 100,000 women diagnosed each year with atypical hyperplasia -- also known as atypia -- into a high-risk category, where they are more likely to benefit from intense screening and use of medications to reduce risk. "By providing better risk prediction for this group, we can tailor a woman's clinical care to her individual level of risk," says Lynn Hartmann, M.D., an oncologist at the Mayo Clinic and lead author of the study.Login Or Register To Read Full Story