Risk profile of breast cancer following atypical hyperplasia detected through organized screening

Background: Few population-based data are available indicating the breast cancer risk following detection of atypia within a breast screening program. Methods: Prospectively collected data from the South Australian screening program were linked with the state cancer registry. Absolute and relative breast cancer risk estimates were calculated for ADH and ALH separately, and by age at diagnosis and time since diagnosis. Post-hoc analysis was undertaken of the effect of family history on breast cancer risk. Results: Women with ADH and ALH had an increase in relative risk for malignancy (ADH HR 2.81 [95% CI 1.72, 4.59] and (ALH HR 4.14 [95% CI 1.97, 8.69], respectively. Differences in risk profile according to time since diagnosis and age at diagnosis were not statistically significant. Conclusion: Estimates of the relative risk of breast cancer are necessary to inform decisions regarding clinical management and/or treatment of women with ADH and ALH