Doctor says women with dense breasts require closer ‘surveillance’ for cancer

Do you know if your breasts are fatty or dense?

You should. If they’re dense, a Washington law that took effect in 2019 requires the letter reporting your mammogram results to include this paragraph:

Your mammogram indicates that you may have dense breast tissue. Roughly half of all women have dense breast tissue which is normal. Dense breast tissue may make it more difficult to evaluate your mammogram. We are sharing this information with you and your health care provider to help raise your awareness of breast density. We encourage you to talk with your health care provider about this and other breast cancer risk factors. Together, you can decide which screening options are right for you.

So what the heck does that mean?

Breasts contain three types of tissue: glandular, fibrous and fatty. Breasts with less fatty tissue (which shows up dark on a mammogram) than glandular and fibrous tissue (which both show up white) are considered dense.

“The problem is cancer is also white on the mammogram,” said Dr. Jennifer Ochsner, a radiologist for Vancouver Clinic’s Breast Care Center. “That’s why we’re interested. The mammogram is harder to read.”

The notification letter often causes confusion and even alarm, said Dr. Sandra Smith, a breast specialist and surgeon at Kearney Breast Center at PeaceHealth Southwest Medical Center.

“What women need most is a good understanding of their overall risk of breast cancer,” Smith said. “Having dense breasts alone does not necessarily mean they are at higher risk of developing breast cancer.”

Calculating overall risk requires considering other factors, like past clinical breast exams, family history and results of genetic testing, she said.

Sometimes primary care providers aren’t comfortable performing that kind of assessment, Smith said, in which case patients should see a breast specialist.

“Expert clinicians need to see the patient, evaluate and make recommendations based on clinical findings, not just radiological findings,” Smith said.

Those at higher risk may require testing beyond annual screening.

“We call it surveillance,” Smith said.

That might include ultrasound or alternating an MRI with a mammogram every six months. (Because mammograms involve radiation, they are spaced 12 months apart.)

MRI finds an additional 14 cancers per 1,000 screenings over mammograms, Ochsner said.

“It’s the most sensitive tool we have,” Ochsner said.

Unfortunately, MRI testing can lead to more false positives and unnecessary biopsies, she said. That’s why the American College of Radiology guidelines for supplemental testing of dense breasts start with 3D mammography, also called digital breast tomosynthesis, for those with otherwise average risk. All mammograms at Vancouver Clinic, as well as most other facilities in the area, are already 3D, Ochsner said. When compared to 2D, 3D mammograms detect one additional cancer per 1,000 women screened.

“It really makes a difference to come in and get your yearly mammogram,” Ochsner said. “It really does save lives.”