MRIs may delay breast cancer care

Data: Mastectomy likelier for those who undergo scan

CHICAGO - Women with newly diagnosed breast cancer who get an MRI scan wait about three weeks longer before their surgery and are far more likely to get a mastectomy than women who have only a mammogram, US researchers said yesterday.

"MRI may not be as good as we think it is," said Dr. Richard Bleicher of the Fox Chase Cancer Center in Philadelphia, who presented his findings at the American Society of Clinical Oncology's Breast Cancer Symposium in Washington. "Those who received an MRI had a three-week delay in the start of their treatment."

"In addition to the treatment delay, we're concerned that the well-documented false-positive rate with MRIs may be leading - or misleading - women into choosing mastectomies," he said.

Bleicher said many women with newly diagnosed breast cancer, including younger women, are getting MRI exams in addition to mammograms. He and colleagues wanted to see whether the tests had any impact on care.

They reviewed the records of 577 breast cancer patients who had been evaluated by a radiologist, pathologist, and a surgical, radiation, and medical oncologist. Of these patients, 130 had MRIs before surgery to remove their tumors, and 27.7 percent of these had a mastectomy. In the non-MRI group, 19.5 percent had a mastectomy.

After adjusting for tumor size, they said women who had gotten an MRI were 80 percent more likely to get a mastectomy.

Bleicher said it is not clear why these women had mastectomies rather than lumpectomies, but it may be related to the higher sensitivity of the MRIs, which are known to have a high number of false-positive findings.

"Rather than having a biopsy to see if those findings are real, women and their doctors may choose mastectomy out of an abundance of caution," Bleicher said.

These findings reinforce a study earlier this year that also found that MRIs increase the chances that a woman would have her breast removed.

The research team looked at the time from diagnosis to cancer treatment and found the women who got MRIs waited 22.4 days longer to have their surgeries.

"I can't tell you that a three-week delay will influence her survival, but I can tell you a three-week delay will increase the anxiety on her part," Bleicher said in a telephone interview.

And they looked to see whether the MRI exams did a better job of helping doctors predict which women could have lumpectomies, in which only the tumor is removed. They found that MRIs were no better than conventional mammograms at this.