The association of breast density with breast cancer mortality in African American and white women screened in community practice

Abstract

The effect of breast density on survival outcomes for American women who participate in screening remains unknown. We studied the role of breast density on both breast cancer and other cause of mortality in screened women. Data for women with breast cancer, identified from the community-based Carolina Mammography Registry, were linked with the North Carolina cancer registry and NC death tapes for this study. Cause-specific Cox proportional hazards models were developed to analyze the effect of several covariates on breast cancer mortality-namely, age, race (African American/White), cancer stage at diagnosis (in situ, local, regional, and distant), and breast density (BI-RADS( ® ) 1-4). Two stratified Cox models were considered controlling for (1) age and race, and (2) age and cancer stage, respectively, to further study the effect of density. The cumulative incidence function with confidence interval approximation was used to quantify mortality probabilities over time. For this study, 22,597 screened women were identified as having breast cancer. The non-stratified and stratified Cox models showed no significant statistical difference in mortality between dense tissue and fatty tissue, while controlling for other covariate effects (p value = 0.1242, 0.0717, and 0.0619 for the non-stratified, race-stratified, and cancer stage-stratified models, respectively). The cumulative mortality probability estimates showed that women with dense breast tissues did not have significantly different breast cancer mortality than women with fatty breast tissue, regardless of age (e.g., 10-year confidence interval of mortality probabilities for whites aged 60-69 white: 0.056-0.090 vs. 0.054-0.083). Aging, African American race, and advanced cancer stage were found to be significant risk factors for breast cancer mortality (hazard ratio >1.0). After controlling for cancer incidence, there was not a significant association between mammographic breast density and mortality, adjusting for the effects of age, race, and cancer stage.

Breast Density and Breast Cancer Risk: A Practical Review

“…14,21,24,[27][28][29] Breast density has also been associated with an increased risk of local and locoregional recurrence of breast cancer but not distant metastasis or survival. 30,31 This finding is consistent with 2 recent large studies that found that breast density was not associated with increased breast cancer mortality or all-cause mortality rates 32,33 ; however, additional research is needed because of the limited studies on this topic. Breast density decreases with advancing age; a large study found that 74% of women in their 40s had dense breasts (D3 or D4) as compared with 36% of women in their 70s.…”

Beyond Breast Cancer: Mammographic Features and Mortality Risk in a Population of Healthy Women

“…In contrast, Chiu et al [37] reported significant increased mortality from breast cancer among women with greater dense tissue, however, breast tissue was broadly categorized as “dense” or “nondense”. Our results vary from studies of breast cancer cases that found null associations between breast density and mortality, however these studies incompletely adjusted for confounders of prognosis such as comorbidities, treatment, tumor size or stage of cancer [19,20,38]. …”

Impact ofCOX2genotype, ER status and body constitution on risk of early events in different treatment groups of breast cancer patients

“…In the present study, breast volume in relation to breast cancer prognosis was assessed rather than mammographic density. While mammographic density is a strong risk factor for breast cancer, its impact on breast cancer prognosis is unclear . Women with large breasts are more likely to have a decreased mammographic density, and mammographic density seems to be less of a breast cancer risk factor for women with larger breasts .…”

“…While mammographic density is a strong risk factor for breast cancer, its impact on breast cancer prognosis is unclear. 48 Women with large breasts are more likely to have a decreased mammographic density, and mammographic density seems to be less of a breast cancer risk factor for women with larger breasts. 19 Dense matter in large breasts may be constitutionally different from that in smaller breasts.…”