Benign breast disease isn’t cancer and isn’t life threatening. Cysts and fatty tumors are examples of benign breast disease. Still, certain types of benign breast disease are known to increase a woman’s risk of breast cancer in the future.
A report in the New England Journal of Medicine highlighted several studies that found that women diagnosed with atypical hyperplasia, a type of benign breast disease, have a higher risk of developing breast cancer than doctors previously thought. The study was published as a special report in the Jan. 1, 2015 issue of the New England Journal of Medicine. Read the abstract of “Atypical Hyperplasia of the Breast – Risk Assessment and Management Options.”
Atypical hyperplasia means that abnormal-looking cells are growing faster than normal. There are two types of atypical hyperplasia:
- atypical ductal hyperplasia, where the fast-growing abnormal-looking cells are in the milk ducts (the pipes of the breast that drain the milk out to the nipple)
- atypical lobular hyperplasia, where the fast-growing abnormal-looking cells are in the lobules (the parts of the breast that make milk)
Earlier studies have shown that women diagnosed with either type of atypical hyperplasia have a risk of breast cancer that’s 4 to 5 times higher than average. This increase is in relative risk, meaning that women with atypical hyperplasia are 4 to 5 times more likely to develop breast cancer than women who haven’t been diagnosed with atypical hyperplasia.
Few studies on atypical hyperplasia have had enough women in them to report the women’s absolute risk of developing breast cancer over a certain period of time.
To get a better idea of how many women would develop breast cancer 5, 10, and 25 years after being diagnosed with atypical hyperplasia, the researchers at the Mayo Clinic followed 698 women diagnosed with atypical hyperplasia between 1967 and 2001. The researchers looked at the women’s medical records and pathology reports and sent the women questionnaires to determine who developed breast cancer and when they developed it.
The researchers found:
- after 5 years, 7% of the women had developed breast cancer
- after 10 years, 13% of the women had developed breast cancer
- after 25 years, 30% of the women had developed breast cancer
The researchers also found that the number of atypical lesions that were found at biopsy affected a woman’s risk of developing breast cancer. As the number of atypical lesions went up, so did the risk of breast cancer. Twenty-five years after being diagnosed with atypical hyperplasia:
- 47% of women with three or more atypical lesions found at biopsy had developed breast cancer
- 24% of women with one atypical lesion found at biopsy had developed breast cancer
Based on the results, the researchers recommend that women diagnosed with atypical hyperplasia be considered to have a much higher-than-average risk of breast cancer. The researchers also said that current breast cancer screening guidelines should be updated to include MRI screening for women with atypical hyperplasia.
“By providing better risk prediction for this group, we can tailor a woman’s clinical care to her individual level of risk,” said Lynn Hartmann, M.D., a Mayo Clinic oncologist and lead author of the report. “We need to do more for this population of women who are at higher risk, such as providing the option of MRI screenings in addition to mammograms and encouraging consideration of anti-estrogen therapies that could reduce their risk of developing cancer.”
If you’ve been diagnosed with atypical hyperplasia, your risk of developing breast cancer is much higher than average. How much higher depends on the characteristics of the atypical hyperplasia, as well as your family history and other health factors. Talk to your doctor about all the aspects of your unique situation. You may want to ask whether more frequent screening or screening with MRI makes sense for you. You also may want to ask your doctor if taking hormonal therapy medicine to lower your risk is a good idea. Together, you and your doctor will develop a risk reduction plan that makes the most sense for you.
Visit the Breast Cancer Risk Factors: Certain Breast Changes page in the Breastcancer.org Lower Your Risk section to learn more about benign breast disease and steps you can take to keep your risk of breast cancer as low as it can be.