MONDAY, April 12, 2004 (HealthDayNews) -- Annual mammograms may not be enough to detect malignancies in women with genetic mutations that increase their risk of developing breast cancer.
Almost half of the women with BRCA 1 and BRCA 2 gene mutations investigated in a new study developed an "interval cancer" within five months of a clean mammogram, said Dr. Ian Komenaka. He is lead author of the study, which appears in the April 12 online issue of Cancer.
An interval cancer is one that is detected between annual mammography scans.
The malignancy had already spread to the lymph nodes within a year in two-thirds of the women with interval cancer. "These cancers are typically more aggressive," Komenaka said. "That makes you concerned. We're thinking one year doesn't seem adequate."
Because the study was a small one, it's not yet clear how often is often enough when it comes to mammography for these high-risk women. There may also be a role for other imaging techniques, such as breast ultrasonography and/or magnetic resonance imaging (MRI).
"I really support the findings of this study," said Dr. Sheldon Feldman, chief of breast surgery and head of the Louis Venet, M.D., Comprehensive Breast Center at Beth Israel Medical Center in New York City. "It confirms what many of us have felt, which is that yearly mammograms are not enough. I think guidelines are coming."
Women who have mutations in their BRCA 1 or BRCA 2 genes have a 60 percent to 85 percent risk of developing breast cancer during their lifetime.
While most guidelines suggest that women with a mutation start annual mammograms five to 10 years before the age of their youngest affected relative, currently there is no consensus on how frequently these women should be screened, the study said. "You start five to 10 years earlier than the youngest affected relative and then you go for a breast exam at least three times a year by a physician, but it doesn't say anything about mammograms," Komenaka said.
The researchers reviewed the medical charts of 13 BRCA mutation carriers who were included in the genetic testing database of Columbia-Presbyterian Comprehensive Breast Center in New York City. Komenaka was a fellow in breast surgery at Columbia at the time the study was conducted, from September 1995 to August 2002.
Of those 13, three (23 percent) did not develop breast cancer, four (31 percent) developed breast cancer that was detected at the yearly screening and six (46 percent) developed breast cancer between annual mammograms. Most of the malignancies that were detected between annual screenings had already spread to the lymph nodes when they were detected.
Although there's not enough data to draw firm conclusions about how frequently mutation carriers should get mammograms, Komenaka suggested three times a year might suffice. "We found that almost half developed their interval cancer in five months, so it would seem like maybe three times a year at least," he said. "Six months wouldn't be good enough."
And because mutation carriers tend to be younger and have denser breasts, there may also be a role for other imaging techniques because mammography is less effective in dense breasts. Even in this small sample, an ultrasound picked up something suspicious when a mammogram did not. "You absolutely still have to do a mammogram because it's the best screening right now, but in addition you can do an ultrasound or an MRI," Komenaka said.
Feldman pointed out the study was completed two years ago. "We're a couple of years on," he said. "I think most centers have evolved to a strategy where, when we have patients in our high-risk surveillance program that we don't rely only on mammography and clinical examination."
Beth Israel also does yearly MRIs for its high-risk patients, as well as targeted ultrasound -- to follow up when another technique has found something suspicious. The center is also starting to use breast endoscopy, in which a miniature endoscope is inserted through the nipple so the lining of the milk ducts, where most breast cancers develop, can be viewed.
More information
For more on breast cancer detection, visit the National Cancer Institute or the American Cancer Society.
