One out of every three MRI's found growths in women that were harmless, according to a new study presented Sunday to the American Society of Clinical Oncology.
The false positive rate in mammograms is one in ten.
Patient Jane Fey's MRI found something her mammograms had missed, two suspicious masses.
But they turned out to be benign, something she learned only after surgery. It's a lesson, cancer researchers say, for women everywhere.
Fey says, "That's the drawback of the MRI. You may go in for surgery that is truly nothing."
Dr. Mark Robson of Memorial Sloan-Kettering Cancer Center says, "The thing I was disappointed by is the number of false positives and potential impact on women who are already scared about getting breast cancer."
MRI's can be a costly choice for women. They are eight times more expensive than mammograms.
Still, Robson, the study's lead author, believes MRI's can be extraordinarily useful, but only for select women at the very highest levels of risk for breast cancer.
He says, "Until we are able to reduce that false positive rate, this really isn't ready for translation to the general population."
Jane Fey says she has no regrets. Her mother and sister had cancer. She had to find out. "I was worried. But what was I going to do, leave it?" she asks. "What if it had been malignant?"
Researchers believe MRI technology could eventually become one of the best screening tools in the fight against breast cancer. But for the near future, mammograms will remain the gold standard.