Caring Currents

New Screening Technology Catches Cancer Better Than Mammograms

Last updated: Sep 10, 2008


A close friend is currently undergoing cancer treatment, including a mastectomy and chemotherapy, to remove a tumor that her doctors now believe grew for several years undetected by regular annual mammograms. The reason? She's among the one quarter of women who have dense breast tissue, which prevents tumors from showing up on routine mammograms.

My friend is one of many women who stand to benefit from a new technology called MBI, molecular breast imaging. Researchers at the Mayo Clinic released results from a large study this week showing that MBI found three times as many tumors as mammograms in women with dense breasts.

Molecular breast imaging, or MBI, is a relatively new tool that's only been in use for about five years. It's more expensive than mammography, but considerably less expensive -- about one fifth the cost -- as a breast MRI. The way it works is that a woman is injected with a short-lived radioactive agent that's absorbed by the breast tissue and "lights up" cancer cells when tracked with a special camera. Among the 940 women followed, mammograms found only three tumors and missed 10, while MBI found 10 tumors and missed three.

The only problem with MBI is the radiation dose, which is 8 to 10 times higher than that received during a mammogram, but the manufacturers of the technology plan future improvements to address that.

Carrie Hruska, the Mayo Clinic researcher who headed the study, offers a clear and helpful explanation in a Mayo Clinic video newsblog.

MBI is currently only available at a limited number of cancer centers, but its use is growing. Meanwhile, more and more experts believe that women who've been told in the past that they have dense or fibrocystic breasts shouldn't rely solely on annual mammograms, but should have an ultrasound or MRI as well.

The American Cancer Society now recommends that women with a high risk of developing breast cancer (defined as a 20 percent or above lifetime risk based on family history and other factors) have MRIs in addition to mammograms.The guidelines stopped short of recommending MRIs for all women with dense breasts, but many doctors will refer for an MRI or ultrasound -- also more and more commonly used -- if a mammogram or physical exam reveals dense breast tissue.

The takeaway: Women with dense breast tissue, which includes many post-menopausal women, need to be proactive about insisting on additional screening beyond mammograms. If this is the case for your loved one or yourself, ask your doctor for a referral for an MRI or ultrasound, as well as about the availability of MBI.

Image of a mammogram contrasted with an MBI courtesy of the Mayo Clinic.