Researchers identify new risk of breast cancer – 03/05/2023 – Health

Scientists have long known that denser breast tissue is linked to a higher risk of breast cancer in women. A new study published in JAMA Oncology adds a new twist, finding that although breast density declines with age, a slower rate of decline in one breast often precedes a diagnosis of breast cancer.

Scientists at Washington University in St. Louis looked at changes in breast density over a ten-year period in 10,000 women who were cancer-free when the study began. About 289 of them were diagnosed with breast cancer in that period; the study compared breast tissue changes with those of 658 similar women who did not develop cancer.

Breast density was highest from baseline in women who developed cancer, and density decreased in all women over time. But when the density of each breast was measured separately, the scientists found a significantly slower decline in the density of the breasts that developed cancer, compared with the other breast of the same patient.

Shu Jiang, lead author of the study and an associate professor of public health at the University of Washington, said the findings could provide an individualized and dynamic tool for assessing a woman’s risk of breast cancer. “I hope they can put this into clinical use as soon as possible. It’s going to make a huge difference,” she said.

“Right now, everyone only looks at density at one point in time,” added Jiang. But women get mammograms at regular intervals throughout their lives, and the density of each breast is measured each time.

“So this information is already available but not used,” she said. Now, a woman’s risk of developing breast cancer can “be updated every time she has a new mammogram.”

Breast density is now a recognized risk factor for breast cancer, although it is one of many. Dense tissue also makes tumors more difficult to detect on imaging tests.

Dozens of US states have begun requiring mammography centers to notify women if they have dense breast tissue. In March, the Food and Drug Administration (FDA) recommended that providers inform women about breast density.

But this is the first study to measure changes in density over time and report a link with breast cancer.

While larger studies need to be done to confirm the findings, Karen Knudsen, CEO of the American Cancer Society, called the data “exciting.”

“This is the first study I’ve seen that specifically looks at changes over time from breast to breast, rather than averaging two breasts, where you might miss those changes,” Knudsen said.

Although women are provided with information about breast density and the risks associated with it, the study suggests that the information could be put to better use.

“We need to monitor women with dense breasts instead of just warning them,” Knudsen said.

A next step might be to look at breast density over time in women taking drugs to prevent breast cancer, to see if density decreases, Knudsen suggested.

“There may be different risk stratification guidelines set to monitor those that are having a much slower decline in tissue density compared to those that are not,” Jiang said.