Women who have been diagnosed with atypical hyperplasia are at higher than average risk for developing breast cancer.
Approximately one in five women who have a mammogram over the next 10 years will require a biopsy to further investigate a suspicious area. About four percent of these women will be found to have an increased number of highly abnormal-looking cells, a condition called atypical hyperplasia. These women have an increased risk of developing breast cancer. The breast cancer may develop in either breast, not just the one that was biopsied.
How much greater is the risk of developing breast cancer for a woman who has had atypical hyperplasia? Think of it this way: In a group of 100 women, five would be expected to go on to develop breast cancer. In contrast, in a group of 100 women with atypical hyperplasia, 19 would be expected to go on to develop breast cancer.