Abstract 776: Temporal changes in mammographic breast density and breast cancer risk among women with benign breast disease

• Published in: Cancer research (Chicago, Ill.) Ill.), 2023-04, Vol.83 (7_Supplement), p.776-776
• Main Authors: Mullooly, Maeve, Fan, Shaoqi, Pfeiffer, Ruth M., Bowles, Erin Aiello, Duggan, Máire A., Falk, Roni T., Richert-Boe, Kathryn, Kimes, Terry, Figueroa, Jonine D., Rohan, Thomas E., Abubakar, Mustapha, Gierach, Gretchen L.
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2023-776

Introduction: Benign breast disease (BBD) is associated with increased breast cancer risk, and the magnitude of this risk is characterized by the severity of the histological classification of the biopsy lesion. High mammographic density (MBD) is an independent risk factor for invasive breast cancer. Given that MBD is altered by endogenous and exogenous factors, its temporal changes may impact future breast cancer risk, but this is poorly studied, particularly among high risk BBD patients. In this study, we examined whether MBD changes following a BBD diagnosis were associated with subsequent breast cancer risk. Methods: We conducted a case-control study within a cohort of 15,395 women aged 18-86 years who were members of the Kaiser Permanente Northwest Region health care system, had a diagnosis of BBD between 1970 and 2012 and were followed through mid-2015. Cases (n=261) were BBD patients who developed invasive breast cancer at least one year after the index BBD diagnosis. Controls were matched (1:1), on age at BBD diagnosis and health plan membership duration and did not develop breast cancer during the follow-up duration. Standardized change in percent MBD per 2 years, categorized as an increase (≥0%), stable/minimal decrease (-5%< to