What You Need to Know: Women with atypical hyperplasia of the breast have a higher risk of developing breast cancer than previously thought, a study has found. 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.
Background: 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, they exhibit some of the early features of cancer.
The Mayo Clinic (USA) team had previously showed that two common statistical risk prediction models (the BCRAT and the IBIS models) performed poorly in women with atypical hyperplasia, underscoring the need to provide alternative approaches for predicting risk in this population.
The Study: To clearly define this risk, the Mayo Clinic team followed 698 women with atypia who had been biopsied at Mayo Clinic between 1967 and 2001. They reviewed pathology and medical records, and used patient follow-up questionnaires to determine which women developed breast cancer and when. The researchers found that after an average follow-up of 12.5 years, 143 women had developed the disease.
- Importantly, the Mayo findings were validated by researchers at Vanderbilt University using biopsies from a separate cohort of women with atypia. Both data sets revealed that at 25 years following biopsy, 25 to 30 percent of these women had developed breast 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.
- Researchers gave an even more accurate estimate of risk by incorporating information from a patient’s pathology specimen. They found that as the extent of atypia 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 foci of atypia in the biopsy had developed breast cancer, compared to only 24 percent of women with one focus.
My Take: Consideration should be given to additional risk-reducing measures for this population of women. Perhaps the option of MRI screenings (in addition to mammograms) and consideration of anti-estrogen therapies such as tamoxifen can reduce cancer risk. While previous research demonstrated that women with atypic have a 4 to 5x increased risk of developing breast cancer, this is a measure known as relative risk. Few studies have had adequate patient numbers and follow-up length to better understand absolute risk – the chance that a woman will develop breast cancer over a certain period of time.
The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.
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- Lynn C. Hartmann, Amy C. Degnim, Richard J. Santen, William D. Dupont, Karthik Ghosh. Atypical Hyperplasia of the Breast — Risk Assessment and Management Options. New England Journal of Medicine, 2015; 372 (1): 78 DOI: 10.1056/NEJMsr1407164
- Mayo Clinic. “Women with atypical hyperplasia are at higher risk of breast cancer.” ScienceDaily. ScienceDaily, 31 December 2014. <www.sciencedaily.com/releases/2014/12/141231190106.htm>.