Breast cancer patients who get newer scans called magnetic resonance imaging are more likely to opt for mastectomies, U.S. researchers reported on Thursday.

The patients who get mastectomies are not living any longer than those who get less radical surgery, the researchers said in preliminary results released ahead of a meeting later this month of the American Society of Clinical Oncology.

The findings suggest that MRIs, which are more sensitive than mammograms, are showing abnormalities that worry patients and doctors alike. They are then opting for total removal of the breast instead of having lumpectomies, in which just the tumor and surrounding tissue is removed.

Dr. Matthew Goetz and colleagues at the Mayo Clinic in Rochester, Minnesota, tracked 5,464 women who had surgery for early-stage breast cancer between 1997 and 2006.

In 2003, just 11 percent of patients got MRIs. By 2006, 22 percent did.

And mastectomy rates declined from 45 percent in 1997 to 30 percent in 2003, but then rose back to 43 percent in 2006.

More than half of the patients who got MRIs opted for mastectomy, compared with 38 percent of the patients who did not have MRIs.

“But the mastectomy rate went up for all women, including women who didn’t get MRI,” Goetz told reporters in a telephone briefing.

“Our data suggests there are additional reasons for the increase in mastectomy rates that we were unable to account for in the study,” he added.

Better breast reconstruction techniques may reassure women they will not be disfigured after a mastectomy, he said. In addition, women who find out they have a genetic predisposition to cancer may opt to have a breast removed.

‘SOME BIAS’

“It may also be that when women are selected to be referred to MRI that there is some bias in who is referred,” said the American Society of Clinical Oncology’s Dr. Julie Gralow, of the University of Washington.

They may have more aggressive disease or hard-to-read mammograms, she said. “What would be a real shame is if women are choosing mastectomy based on MRI readings (of lesions) that are not biopsied ... and they are having mastectomies they don’t need,” she said.

“Some women just choose to maximize their risk reduction by removing more breast tissue. That’s not necessarily a wrong choice,” Gralow added - so long as women understand that the additional surgery will not necessarily translate into a longer life, although it may mean less worry about having to be treated for tumors that come back.

Dr. Allen Lichter, Chief Executive Officer of ASCO, said radiation therapy is standard after breast surgery and should remove any small tumors that cannot be cut out.

“Now MRI sees these things we knew were there,” Lichter told Reuters in an interview.

“They are saying, ‘Oh, my.’” But, Lichter pointed out, radiation gets those lesions anyway.

“This is true for almost every new test that is introduced in medicine,” added Dr. Richard Schilsky of the University of Chicago, president-elect of ASCO.

Computed tomography, or CT, scans had a similar pattern when first used to diagnose lung cancer, he said. “Lo and behold, the CT scan showed all these little nodules in the lung - the vast majority of which were benign,” Schilsky said.

Just this week researchers reported that using ultrasound in addition to mammograms helped spot 28 percent more breast tumors, but it resulted in four times as many false alarms.

By Maggie Fox, Health and Science Editor
WASHINGTON (Reuters)