I Didn’t Get Why Dense Breasts Mattered Until I Got Cancer at 46

One in eight women will be diagnosed with breast cancer in their lifetime—and in 2022, I became one of them. At age 46, I thought I was doing everything right: I didn’t smoke, rarely drank, exercised, and ate well. What I didn’t realize was that my greatest risk factor was something beyond my control: I had dense breasts.

Dense breasts are common—about half of women in their 40s or older have them. Thanks to an FDA mandate that went into effect last year, mammogram reports must now include whether a woman has dense breasts.

You might be tempted to skim past that line on your report, as I did years ago, not realizing its importance.

Don’t. That diagnosis could save your life.

I didn’t grasp why dense breasts were problematic until after I got cancer. Put simply, breasts are made up of three types of tissue: glandular, fibrous, and fatty breast tissue. Dense breasts have more glandular and fibrous tissue, and less fatty breast tissue.

This matters because most breast cancers begin in glandular and fibrous tissues, specifically the milk ducts or lobules. The more of this tissue you have, the greater your risk.

People with extremely dense tissue, like me (around 10% of women), have a four-to-six-times-higher risk than those with low or no dense tissue. For perspective, having a first-degree relative with breast cancer only doubles your risk.

Dense tissue also makes tumors harder to detect on mammograms. Both cancer and dense tissue appear white, while fatty tissue is dark and helps tumors stand out. Radiologists say it’s like trying to find a polar bear in a snowstorm: Both the bear (tumor) and the snow (dense tissue) blend together. This explains why mammograms can miss nearly half of cancers in women with extremely dense breasts, which is what happened to me.

While we can’t change our breast density, we can improve detection. If you have dense breasts, your mammogram report may suggest talking with your doctor about additional imaging, such MRIs or ultrasounds, which don’t use radiation and are better at finding cancer in dense tissue.

An MRI helped catch my cancer early. I started high-risk screening in 2019 because of my dense breasts and my mom’s breast cancer diagnosis at 49. I reluctantly began regular MRI scans, staggered six months after my mammogram so I’d be screened twice a year. I really didn’t think I needed them, and skipped one or two during Covid.