Abstract
AimBreast density is a risk factor for breast cancer. As density changes across a woman's life span, we studied for how long a single density measurement taken in (post-)menopausal women remains informative. MethodsWe used data from Singaporean women who underwent a single mammography screen at age 50–64 years. For each case with breast cancer diagnosed at screening or in the subsequent 10 years, whether screen detected or diagnosed following symptoms, two age-matched controls were selected. We studied the excess risk of breast cancer, calculated as an odds ratio (OR) with conditional logistic regression and adjusted for body mass index, associated with 26–50% and with 51–100% density compared with ≤25% density by time since screening. ResultsIn total, 490 women had breast cancer, of which 361 were diagnosed because of symptoms after screening. Women with 51–100% breast density had an excess risk of breast cancer that did not seem to attenuate with time. In 1–3 years after screening, the OR was 2.22 (95% confidence interval [CI]: 1.07–4.61); in 4–6 years after screening, the OR was 4.09 (95% CI: 2.21–7.58), and in 7–10 years after screening, the OR was 5.35 (95% CI: 2.57–11.15). Excess risk with a stable OR of about 2 was also observed for women with 26–50% breast density. These patterns were robust when the analyses were limited to post-menopausal women, non-users of hormonal replacement therapy and after stratification by age at density measurement. ConclusionA single breast density measurement identifies women with an excess risk of breast cancer during at least the subsequent 10 years.
Highlights
About 40% of women have heterogeneously or extremely dense breasts, of which ca. 5e10% have extremely dense breasts (BI-RADS 4; typically !75% dense tissue) [1,2]
In an extensive meta-analysis, adjusted for age, the relative risk (RR) of breast cancer in women with 50e74% dense breast tissue approached three (RR: 2.92, 95% CI: 2.49e3.42) compared with women whose breasts are composed of >95% fatty tissue, while the relative risk in women with !75% dense tissue was estimated to be about 4e5 (RR: 4.64, 95% CI: 3.64e5.91) [3]
Given this dynamic in breast density, we investigated for how long a single density measurement taken at !50 years of age remains predictive of the excess risk of breast cancer
Summary
About 40% of women have heterogeneously or extremely dense breasts (as defined by Breast ImagingReporting and Data System [BI-RADS], categories 3e4; this typically involves dense tissue in !50% of the breast), of which ca. 5e10% have extremely dense breasts (BI-RADS 4; typically !75% dense tissue) [1,2]. 5e10% have extremely dense breasts (BI-RADS 4; typically !75% dense tissue) [1,2]. In a US study, taking into account symptomatic cancers diagnosed 2 years after a negative screening mammogram, the mammographic sensitivity was 72% overall, but only 30% in women with extremely dense and 60% in women with heterogeneously dense breasts, whereas, it was 80% in women with predominantly fatty breasts [6]. Breast density changes across a woman’s life course [7,8]. Most prominently, it decreases with age and, independently, with menopausal transition, as fibroglandular tissue is replaced with fat [9,10]. While density is associated with several non-modifiable factors such as genetics and race [11,12], various modifiable factors play a role such as women’s lifestyles [7,11,13e17] and use of medication, such as hormonal replacement therapy (HRT), which increases density, or tamoxifen, which reduces it [7,17e22]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
