Recently, a team of scientists in Norway confirmed women with dense breasts have higher cancer rates than those with non-dense breasts.
The study, which included over 100,000 women and more than 300,000 breast screenings, confirmed women with dense breasts were more often recalled for additional screening, had higher breast biopsy rates and had higher odds of screen-detected and interval breast cancers (those found between screenings) as compared to women with non-dense breasts. The study was conducted using automated software and backs up previous research linking breast density and higher breast cancer rates.
Women’s breasts are made up of milk-producing glands, milk ducts, supportive tissue and fatty tissue. Just as every woman is different, so are her breasts. Breasts that contain primarily fatty tissue are non-dense while those with more supportive tissue have a higher density. Nearly half of all women who undergo mammography have heterogeneously dense (majority of tissue is dense) or extremely dense (nearly all the tissue is dense) breasts.
Since dense breast tissue appears white on a mammogram – just like breast tumors, scientists conducting the study found mammographic sensitivity was significantly reduced in women with dense breasts, sometimes delaying diagnosis and leading to more advanced, larger cancers.
Dense breasts do not feel differently from non-dense breasts and are typically diagnosed through mammography.
Study authors suggest additional studies focused on the cost-effectiveness of more frequent screenings or additional screening tools such as MRI and ultrasound for women with dense breasts are warranted. Additionally, they recommend further research to gauge the risks and benefits of automated mammographic software.
It is important for women to know their own breasts and to follow current breast screening guidelines. The American Cancer Society recommends women have yearly mammograms beginning at age 45. Women at higher risk due to family history, a breast condition or other reasons should discuss earlier screening with their medical provider. By age 55, some women may move to mammograms every other year, but this decision should only be made under medical advice.
Dr. Gaelyn Scuderi, Director of Imaging at Ackerman Cancer Center, has also written on the topic of breast density and cancer risk. You can read her blog post here.