A study published this week in the Journal of the American Medical Association has received extensiveÂ media attention because it found that ultrasound was able to find some cancers that mammography missed.Â
But, as always, there were caveats.
One: ultrasound found a lot of things that were not breast cancer, leading to many unnecessary tests.Â The study found that by adding screening ultrasound (using ultrasound to look at the whole breast) to mammography, 55% more cancers were found in high risk women. That sounds like a lot. But in fact there were only 12 more cancers in the whole study that were detected only by ultrasound. Â But of Â the additional 233 women who needed biopsies because their additional ultrasound “saw something” only 20 had cancer.Â
Two: As I point out in Deborah Kotz’s blogÂ On Women on the U.S News & World Report website, there is no evidence that adding ultrasound to mammography will actually reduce your risk of dying of breast cancer.
We’ve long assumed thatÂ finding a cancer early will reduce your chance of dying. However, recent data suggests that not all cancers are the same. Some are more aggressive than others and just finding them early may not be enough.Â Likewise, some cancers are so slow growing that finding them early isn’t as important in terms of survival. The researchers haven’t followed these women long enough–and it would take years–to know if adding ultrasound really did save lives.
Three: Breast ultrasound is expensive, takes a lot of time to do, and is not available at all medical centers.
Four: MRI is better than ultrasound. In March 2007 the American Cancer Society releasedÂ new breast cancer screening guidelinesÂ which recommend that high-risk women receive an MRI and a mammogram.Â
Bottom-line: Mammography, which is far from perfect, remains the best test for women at average risk of getting breast cancer. For those who are high-risk, adding MRI to mammography is a good choice, but MRI cannot be used instead of mammography.