Women at high risk for breast cancer are generally advised to have one mammogram and one magnetic resonance image scan every year, and they usually schedule them around the same time, along with a hands-on examination by a doctor. The idea is to get three different views of what's going on in the breasts.
MRIs pick up more abnormalities than mammograms, although they have a higher rate of a false positive
But what about that 12-month stretch in between when no one's taking pictures and the woman herself is the only one checking for lumps?
A pilot study presented Saturday at the 31st annual San Antonio Breast Cancer Symposium, in Texas, found that alternating between screening types every six months may turn up cancer earlier than the once-a-year routine -- a result that researchers didn't expect.
"We didn't know if by staggering [the imaging], we would pick up more cancer," says study author Huong Le-Petross, M.D., a radiologist at the University of Texas M.D. Anderson Cancer Center, in Houston. "We were looking for an option for women to get screenings every six months." Health.com: Top 10 breast cancer stories of 2008
The study of 334 women included 86 high-risk subjects who were alternating methods. Mammograms picked up three of the nine cancers detected in the high-risk women, and they were confirmed by MRIs. Five were picked up on MRI, but didn't show up on a mammogram, and one tumor was missed by both types of tests. The majority of tumors showed up on an MRI. Health.com: Do you have breast cancer in your family?
"The MRIs saw the most cancers and the size is small," and that makes them easier to treat, says Le-Petross. The superiority of the MRIs was not surprising. The powerful magnetic machines do pick up more abnormalities than the X-rays in mammograms, although they also have a higher chance of a false-positive -- a suspicious spot that a biopsy shows isn't cancer.
William Audeh, M.D., an oncologist who's developing a breast-risk-reduction program at Cedars-Sinai Medical Center, in Los Angeles, California, says Le-Petross' study is a timely effort to measure a practice that's already pretty common in some centers nationwide.
"It makes sense [for high-risk women] to have some sort of imaging at six months," says Audeh. And there's no question that MRIs are the best tool available for screening in this group, he adds. Health.com: Five simple things that could cut your breast cancer risk
So why stick with both tests? If MRIs do so well, why shouldn't women at high risk drop mammograms completely and have MRIs twice a year? Le-Petross would like to compare an MRI-only routine against the current standard and find out for herself.
However, mammograms do have one special edge over MRIs.
"The one area that mammograms do pick up is microcalcifications," notes Audeh, "and there are some women whose abnormalities are [only] picked up that way."
Here's another reason MRIs can't go solo just yet: Health insurance only covers one such screening in a year, and MRIs are expensive, at $1,000--$1,500 per image. Insurance companies go by the American Cancer Society guidelines for breast screening, which recommend one mammogram and one MRI a year for women who have a lifetime breast cancer risk of 20 percent or more. Health.com: A high-risk woman opts for prophylactic mastectomy
The question of who qualifies as high-risk was a dominant theme at the San Antonio conference this year. Health.com: How to cut your breast cancer risk at any age
Women are generally in this group if they have multiple cases of breast or ovarian cancer in the family, a positive result on the BRCA breast cancer gene-mutation test, a personal history of the disease, or a biopsy showing atypia or lobular carcinoma in situ.
Regular screenings have been doctors' most solid advice for women who do fall into the rough definitions of this category. Now there's this too: Annual visits aren't the careful, conservative option anymore -- they're the minimum.
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