Breast Density and Breast Cancer Risk

Woman looking into camera with serious expression on her face

Many of our patients have had a lot of questions following recent media attention about the risk of breast cancer, density, and MRI screening. And while we have always routinely calculated the risks for all our patients and recommended personalized screening options, we wanted to address some of these concerns here.

We feel that the assessment model mentioned in the media overestimates this risk by putting too much emphasis on lifetime risk over shorter term chances of diagnosis (5-10 years) and overusing MRIs. However, we are happy to discuss any changes or additional testing options if you feel this will help give you peace of mind.

What Is Breast Density?

We define breast density based on how the tissue appears on the mammogram. The word ‘density’ implies how much milk-producing glandular tissue we think is inside the breast.

How Common Are Dense Breasts?

Of the entire population, mammogram density stratifies women into four density categories:

  • Category A: 10% of all women. Less than 25% of the breast is milk producing tissue, the remainder is fat (“mostly fatty”)
  • Category B: 40% of all women. active tissue makes up 25-50% of the breast (“scattered elements”)
  • Category C: 40% of all women. 50-75% of the breast is glandular (“heterogeneously dense”)
  • Category D: 10% of all women. The breast is >75% gland tissue (“extremely dense”)

Does Having Dense Breasts Increase Your Risk of Breast Cancer?

Women with dense breast tissue do have a slightly higher risk of developing breast cancer. This is because the more milk-producing glandular tissue there is in the breast, the more opportunities for more types of cancer cells.

Is Additional Screening Necessary?

Categories A and B consist of primarily fatty breasts; therefore, we don’t recommend additional screening. Categories C and D contain high enough density for recommended additional screening ultrasounds with consideration for screening MRI’s. 

Overall, 50% of the population has breast tissue density that we recommend additional screening tests for. We are accustomed to seeing it, especially in younger women. We haven’t been able to demonstrate that routine screening MRI’s, even in high-risk groups, make cancers more curable or offer better outcomes or survival odds.

Additionally, MRI uses a heavy metal dye called gadolinium that produces a 15-30% false positive rate requiring additional studies, a 10% biopsy recommendation, but less than 1% chance of finding a cancer. This can create an anxiety-provoking process for many.

While we do utilize MRIs in our care, we do not recommend annual MRIs for all patients with a certain risk percentage. We strongly believe that we should discuss this on a case-by-case basis while understanding the screening pros and cons. Talk to your doctor regarding your best plan of action.

Contrast-Enhanced Mammography

We’re thrilled that Bedford Breast Center will soon offer contrast-enhanced mammography! We expect it to have efficacy of seeing specific cancer changes, equal to or better than MRI (with a lower false positive rate and no heavy metal dye). Furthermore, we pride ourselves on staying on top of the latest breast cancer/risk recommendations and can reassure you that we are taking all proper steps in your care.

If you have additional questions, contact Bedford Breast Center or call (310) 278-8590 to schedule a consultation with one of our breast specialists.

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