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Minn. Doctors Must Now Tell Patients About Dense Breast Tissue

MINNEAPOLIS (WCCO) -- October is known as Breast Cancer Awareness month. And this year, Minnesota has a new law in place that changes what doctors are required to reveal about a woman's mammogram result.

Minnesota doctors are now required to notify women if they have dense tissue in their breasts. It's a condition that can mask the presence of a tumor on an X-ray.

Doctors say about 40 percent of women have dense breast tissue.

After a woman undergoes a mammogram, they typically get a letter in the mail stating everything looked normal, or a phone call asking them to return for more testing.

This new mandate means that some women will also see an additional detail on the letter that states they're fine. It will show they have dense breast tissue, and that means their cancer screenings are more difficult to read.

"So this law is really about making sure women get the most information they possibly can out of their mammograms," said Dr. Kathryn Ruddy, a breast medical oncologist at the Mayo Clinic.

She treats women undergoing chemotherapy after a breast cancer diagnosis.

"Dense breasts are associated with a higher risk of breast cancer and also dense breast tissue is harder to see through with a mammogram, so the mammograms are less good at picking up breast cancer in women with dense breasts," she said.

Ruddy showed us Wednesday examples of images that radiologists study after a mammogram.

"This is fatty breast tissue, which would be easily visualized with mammogram," Ruddy said, looking the the first image. "And a breast cancer would be more easily found in fatty tissue than dense tissue."

The second image showed what dense breast tissue looks like.

"So there is more connective tissue in a dense breast, and that's why it looks whiter than the fatty breast we just looked at. When you see a cancer on a mammogram, it usually looks white, so it is more difficult to pick out a cancer when the background is white," she said.

Dense breast tissue is more common in younger women.

"We certainly don't want women with dense breasts to think that they shouldn't be getting mammograms. They definitely should. Mammograms pick up tens of thousands of breast cancers annually in women with dense breasts in the United States," she said.

Minnesota is the 16th state to mandate that doctors disclose dense breast tissue in their reports to patients. There was little debate about it in the state Legislature. It was part of a health omnibus bill that passed.

The Mayo Clinic recommends that women get their first mammogram at age 40.

What should a woman do if they have dense breast tissue? There are no national guidelines for that. It's still being debated in the medical community.

The general thought is that knowledge is power. The letter women get with their result recommends that they talk with their doctor about additional testing options, like breast ultrasounds and breast MRIs.

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