Personal history of atypical ductal hyperplasia and risk of multifocal breast cancer among newly diagnosed women: Implications for workup and management.

Abstract

300 Background: Multifocal breast cancer (MFBC) is associated with a higher risk of mortality than unifocal and often changes evaluation and management compared to unifocal breast cancer. Although there are known risk factors for invasive breast cancer, including atypical ductal hyperplasia (ADH), none have been explicitly associated with risk of MFBC. Our objective was to determine if there is an association between ADH and MFBC to help guide clinical decisions in workup and management in women with newly-diagnosed breast cancer. Methods: Using data (1999-2008) from the New Hampshire Mammography Network (NHMN) – a longitudinal breast imaging registry, including pathology data – we identified a cohort of 3,039 women (median age: 59) with a diagnosis of invasive or in situ breast cancer, and ascertained all prior biopsy results if applicable. We performed multivariable logistic regression to test the association of ADH with MFBC v. unifocal, adjusting for other benign breast disease, family history, breast density, age, race, and DCIS/invasive. Results: Of the 3,039 women with breast cancer during the study period, 498 had a diagnosis of ADH (16.4%) and 277 had MFBC (9.1%). Women with a history of ADH had over a two-fold greater likelihood of having MFBC compared to women without an ADH diagnosis (OR: 2.20, 95% CI: 1.61-2.99). No notable difference in this association was noted for DCIS v. invasive, and no other risk factors were found to have a significant difference, except for number of biopsies. Conclusions: We found that ADH diagnosis is positively associated with MFBC among women with a diagnosed invasive or in situ breast cancer. Our results suggest that among women with a newly diagnosed breast cancer, history of an ADH diagnosis increases the pre-test probability of MFBC, which may influence evaluation of extent of disease, such as adding breast MRI, and ultimately in treatment and management.