They cannot feel the risk, but it is there, and it can make breast cancer harder to detect. Almost half of American women in the 40-74 year-old age group have what is called dense breast tissue. The breasts are made up of milk glands, fatty tissue and dense breast tissue. Dense breasts do not look or feel differently than those which are less dense. That is part of the challenge for cancer-fighting physicians like Josie Alpers, MD, a mammography and radiology specialist with the Avera Medical Group Radiology.
“Dense breast tissue is an independent risk factor for breast cancer. Research shows it increases risk for breast cancer 1.5-2.5 percent,” Alpers said.
Alpers explained that physical exams cannot determine the density of breast tissue and that women with less – or no – dense tissue can still get breast cancer. Mammography is the only way for physicians to tell whether or not the tissue is dense. “It is more common in younger, thinner women. However, studies show that gaining weight and going through menopause actually increases a woman’s risk for breast cancer,” she said. “Dense tissue is normal. It’s not a disease, but it can make it harder to detect cancerous tumors.”
Shades of gray make up the appearance of a mammogram, and the shades indicate the types of tissue that make up the breast, Alpers said. Fatty tissue appears as dark areas, while dense tissue will appear as lighter area. Tumors also show up as light – or nearly white – areas, which can lead to difficulties in pinpointing their locations.
“Since tumors display as white on mammograms, much like dense tissue, the tumors in that tissue can be hidden,” she said. “But with the advent of digital, and now 3-D breast tomosynthesis mammography, cancer can be better differentiated from dense tissue.”
Another tool Alpers can use is contrast-enhanced spectral mammography, or CESM. Using this method allows her and other Avera cancer physicians to detect the tumor, even in situations where the dense breast tissue makes it hard to see.
“Contrast-enhanced spectral mammography allows us to avoid false positives, and it works based on the physiology of the breast,” Alpers said. “It’s important for all women to realize that we don’t do additional testing in the case of dense breasts. The American College of Radiology doesn’t recommend additional imaging, especially for women who have average risk. But for women who have an abnormal screening mammogram, a gene mutation, or have a distinct family history, contrast-enhanced spectral mammography and MRI are options. MRIs are more costly and time-consuming than contrast-enhanced spectral mammography.”
Alpers recommends any woman with questions about their breast density discuss it with their doctor during their next mammogram appointment.
“”Breast density is – like many things – a single factor, one to be considered closely, but not a dire warning,” she said.