Researchers from the University of Manchester have recently published a new study entitled Raised mammographic density: causative mechanisms and biological consequences. 

Key outtakes from the study, published in 2016 in Breast Cancer Research, provide a clear summary as to the current state of the understanding of high mammographic breast density.

• “High mammographic density is the most important risk factor for breast cancer, after ageing.”
• “Epidemiologically, the risk of developing breast cancer is significantly greater in those women with raised MD (‘mammographic density’).”
• “MD is therapeutically modifiable, patient tolerance to long-term endocrine treatments (‘Tamoxifen’) is low…”
• “MD is highly variable between women, ranging from a minimum of 3 % by volume, to very high levels of 25 % (Volpara measurements; the latter high level is equivalent to 75 % density in VAS).”
• “The current understanding of the link between MD and breast cancer was reviewed extensively in 2014, with over 180 of the previous papers on this topic examined. Numerous studies, originating in 1976, have revealed that high MD is strongly linked with the susceptibility for breast cancer.”
• “Indeed, women with high-dense breasts have a four-to sixfold greater risk of getting cancer than those with the lowest MD density.”
• “More recently, it was found that the percentage of high MD is a stronger risk factor for breast cancer than absolute dense area.”
• “Breast cancer is a major disease that affects 12 % of the female population at some point during their lifetime, and is the global cause of death for nearly 500,000 women per year.”
• “Although there is a link between BMI and cancer, there is no direct association between BMI and MD.”
• “Regardless of the role played by cellular hypertrophy, an altered stromal composition in women aged 50–69 years correlates with increased MD, although there is no difference in the amount of epithelial lobules or ducts.”
• “It seems likely that raised MD is associated with a complex pattern of upregulation and downregulation of ECM proteins.”
• “There are several therapeutic strategies to reduce or eliminate breast cancer from those who have it. The American Cancer Society sanctions six major kinds of treatment, including surgery, radiation therapy, chemotherapy, hormone therapy, targeted therapy, and bone-directed therapy.”
• “With high MD now being recognised as a major risk factor for cancer, the therapeutics that are used so far to reduce density and thereby to potentially protect against cancer arising from high MD mainly include selective ER modulators. For example, the anti-oestrogenic compounds tamoxifen, its relatives such as raloxifene and aromatase inhibitors, are prescribed to patients with high MD but yet have no signs of acquiring breast cancer.”
• “Interestingly, breast cancer-specific survival occurred in tamoxifen-treated women who showed a reduction in MD.”
• “…taking advantage of combined strategies to detect and/or revert high MD could reduce the incidence and mortality of breast cancer by more than 20 %.”