Association of high breast density with adverse effects of the breast cancer screening program: A retrospective study

To compare the following rates between women with high breast density and women with low breast density that have participated in a breast cancer screening programme in Spain: recall rate (RR), false positive rate (FPR) and detection rate (DR).

We carried out a retrospective observational study in two tertiary hospitals in Barcelona. We included asymptomatic women aged 50-69 years, who attended the breast cancer screening programme between 1 January and 31 December 2022. Mammograms included two bilateral projections and breast density was assessed visually by expert radiologists, following the 5th edition BI-RADS recommendations. RR, FPR and DR were compared between the group of patients with high breast density (ACR-C, ACR-D) and the group with low breast density (ACR-A, ACR-B).

The study included 18,193 women screened in 2022, of which 37.5% (6830 women) had dense breasts. It was noted that the proportion of women with high breast density decreased as age increased. The group of women with dense breasts had a higher RR (5.5% vs. 2.8%) (P-value < .001) and a higher FPR (49.6/1000 vs. 24.8/1000) (P-value < .001) than those with low breast density. Furthermore, the DR for breast cancer was higher for women with dense breasts (5.85/1000 vs. 3.6/1000) (P-value = .013).

High breast density is associated with increased RRs and FPRs in our screening programme. It is also related to a higher breast cancer DR.