The extent of atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH) does not significantly contribute to breast cancer risk, a new study published online ahead of print in the journal Cancer has shown.1

Although previous research has demonstrated an association between atypical hyperplasia on a benign breast biopsy specimen and breast cancer risk, the relation between the type or extent of ADH or ALH and the magnitude of the breast cancer risk is not clear.

For the nested case-control study, researchers identified 488 cases of women with breast cancer and prior benign breast biopsy findings matched with 1907 controls who had prior benign breast biopsy findings but no breast cancer.

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Results showed no significant association between the extent of atypia and breast cancer risk among women with ADH or ALH. In other words, women with ADH with 1 or 2 foci of atypical hyperplasia had a similar risk for developing breast cancer compared with those with 3 or more foci. Women with ALH with 3 more foci had a higher risk than those with less than 3, but the difference was not statistically significant.

“The lack of a significant dose-response relation between the extent and type of atypia and breast cancer risk suggests that it would be premature to use the extent of atypia to influence management decisions for women with ADH or ALH,” the authors note.


1. Collins LC, Aroner SA, Connolly JL, et al. Breast cancer risk by extent and type of atypical hyperplasia: an update from the Nurses’ Health Studies [published online ahead of print November 13, 2015]. Cancer. doi:10.1002/cncr.29775.