DEAR DOCTORS: I am a 65-year-old woman in remission from breast cancer. I had a single mastectomy and now have an annual mammogram on my remaining breast. I recently learned about 3D mammograms. Is there any advantage of this type over the standard kind? I am told I have dense breast tissue.
DEAR READER: A mammogram is a scan that uses low-dose X-rays to examine breast tissue. They are used to screen for breast cancer and also as a diagnostic tool. Although the idea for mammography was first proposed in the 1920s, it wasn't until the 1960s that the modern procedure we know today came into widespread use. In the 1990s, the idea for a 3D mammogram, also known as digital breast tomosynthesis (DBT), gained momentum. Clinical trials into the efficacy of DBT began in 2008. Three years later, the technique, which delivers a more detailed view of the breast, received Food and Drug Administration approval.
The standard 2D mammogram uses a top and side view of the breast to provide a flat image of the breast tissue. The 3D mammogram, by contrast, grabs multiple images from a variety of angles. A computer program then combines them into a single image that offers 3D depth and great detail.
While standard mammograms are still a useful diagnostic tool, for some women, the 3D technique is a better choice. To understand why, we should take a closer look at the tissues that form the breast.
Although the breast appears to be a single structure, it is actually composed of several types of tissue. This is important because each of them photographs differently in an X-ray. Fatty tissues appear as clear, dark areas on a mammogram. But the glandular tissues that produce, store and deliver milk and the connective tissues that support and shape the breast appear as a solid white mass.
When someone has dense breasts, as you do, it means they have a high proportion of connective and glandular tissue. This makes it easier for cancers and other problems to go undetected in a standard mammogram. The 3D mammogram, with its multiple views, will offer a better diagnostic field of vision. It is possible that even 3D mammography can be inadequate as a diagnostic tool for some women with dense breast tissue. In those cases, additional types of scans may be needed to supplement the information in a mammogram. These include ultrasound, which uses sound waves to map the tissues, or magnetic resonance imaging (MRI), which creates images with the use of magnetic fields and radio waves. While these tests are more detailed than the 2D or 3D mammogram, they may not be covered by insurance.
As a breast cancer survivor with dense breast tissue, a 3D mammogram is a wise choice. Ultrasound or MRI tests may also be recommended as follow-up care. We urge you to discuss your options with your oncologist. If they are reluctant to explore alternatives to the standard mammogram, it would be wise to seek a second opinion from a physician who is well-versed in the diagnostic challenges of dense breast tissue. Universal Features Syndicate
Dr Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health.
