In a study involving over 1,100 women diagnosed with breast cancer, researchers found that 48.7 percent of women alive or dead from other causes at a median follow-up of 11.7 years had moderately dense breasts. They also found that 46 percent of women who died from breast cancer at a median-follow-up of 5.3 years had moderately dense breasts.
There is no evidence of decreased mortality for women with dense breasts, according to newly published research.
For the retrospective study, recently published in The Breast, researchers reviewed data from 1,116 women who originally participated in the Malmo Diet and Cancer Study (MDCS) and were diagnosed with invasive breast cancer between 1991 and 2014. The study cohort was comprised of 914 women who were alive or dead from other causes at a median follow-up period of 11.7 years, and 202 women who had died from breast cancer within a 5.3-year median follow-up period.1
Among women who were alive or had died from other causes, 48.7 percent had moderately dense breasts in comparison to 46 percent of women who died from breast cancer, according to the study. The researchers found that 38.1 percent of women who died from breast cancer had dense breasts in comparison to 33.3 percent in the cohort who were alive or dead due to other causes.1
Further evaluation employing the BI-RADS 5th edition classification criteria in a subset of 376 women found that 32.2 percent of breast cancer survivors or those who died from other causes had heterogeneously dense breasts in comparison to 31.8 percent of women who died from breast cancer. Additionally, the study authors found that 6.8 percent of women who died from breast cancer had extremely dense breasts in comparison to 8.1 percent for breast cancer survivors and those who died from other causes.1
While previous research utilizing the MDCS database found impaired survival in women with dense breasts in comparison to those with fatty breasts, the researchers said key differences with their study included the inclusion of the BI-RADS 5th edition classification and comparing women with fatty and moderately dense breasts to women with denser breasts.1,2
“Neither in these analyses did we find evidence for impaired survival in women with denser breasts, when taking the whole study population into account,” wrote study co-author Hanna Sartor, M.D., Ph.D., who is affiliated with the Department of Translational Medicine, Diagnostic Radiology at Lund University in Lund, Sweden, and the Unilabs Breast Unit at Skane University Hospital in Malmo, Sweden, and colleagues.
(Editor’s note: For related content, see “Should Race and Ethnicity Factor into Starting Ages for Mammography Screening?,” “Looking at Next Steps to Reinforce National Breast Density Notification” and “Mammography Study Shows 22 Percent Higher Incidence of Dense Breasts in Women with a Family History of Breast Cancer.”)
In regard to tumor appearance on mammography, the study authors noted that spiculated tumors were more common in breast cancer survivors and those who died from other causes (42.7 percent) in comparison to 34.1 percent for women who died from breast cancer. Ill-defined breast tumors were more common among women who died from breast cancer (28.2 percent) in comparison to 18.5 percent in breast cancer survivors and those who died from other causes.
However, Sartor and colleagues pointed out that long-term follow-up found no significant results linking tumor appearances on mammography to breast cancer prognosis.
“Breast cancer is a multifactorial disease, and the influence of tumor appearances might not be strong enough to affect long-term prognosis, even though they are associated with cancer characteristics at diagnosis,” noted Sartor and colleagues.
In regard to study limitations, the authors noted the combination of data from a single center and a study cohort comprised of generally healthier women with a slightly higher educational level in comparison to the average female population may limit extrapolation of the findings to a broader audience.
1. Sturesdotter L, Larsson AM, Zackrisson S, Sartor H. Investigating the prognostic value of mammographic breast density and mammographic tumor appearance in women with invasive breast cancer: the Malmo Diet and cancer study. Breast. 2023. Available at: https://www.thebreastonline.com/article/S0960-9776(23)00498-8/fulltext . Published May 22, 2023. Accessed May 25, 2023.
2. Olsson A, Sartor H, Borgquist S, Zackrisson S, Manjer J. Breast density and mode of detection in relation to breast cancer specific survival: a cohort study. BMC Cancer. 2014;14:229. doi: 10:1186/1471-2407-14-229.