SATURDAY, Sept. 6 (HealthDay News) -- Women who receive an MRI after a new diagnosis of breast cancer not only delay the start of treatment, but they are also more likely to have a mastectomy, as opposed to breast-conserving surgery.

And despite clear evidence of a benefit, MRI use is on the rise, said the authors of a study expected to be Saturday at the American Society of Clinical Oncology Breast Cancer Symposium in Washington, D.C.

"There was no rhyme or reason as to when MRIs are being used," said study author Dr. Richard J. Bleicher, co-director of the breast surgery fellowship at Fox Chase Cancer Center in Philadelphia. "This tells us that routine use of MRI in breast cancer does not appear to help us with treatment choices, and it provides a small delay in work-up time."

Although MRI is recommended to screen high-risk women for breast cancer, its use in newly diagnosed breast cancer patients has been controversial.

"There's been a lot of hype about MRI. It is more sensitive . . . and people have assumed that because it is more sensitive that it will improve outcomes in women either for screening or breast cancer, but there's just about no data to suggest that," Bleicher said.

Bleicher and his team analyzed the medical records of 577 women with breast cancer, 130 of whom had had an MRI prior to treatment.

The women who had MRIs tended to be younger (52.4 years versus 58.8 years) but otherwise there appeared to be no difference between the two groups in breast cancer risk factors or in characteristics of the disease.

Having an MRI almost doubled the odds that a woman would undergo a mastectomy, adding to research presented in the spring by Mayo Clinic researchers who found that the mastectomy rate has increased to levels close to those not seen since 1997.

MRIs also delayed pre-treatment evaluation by about three weeks and did not help surgeons better gauge which patients would be good candidates for lumpectomy as opposed to mastectomy.

Although Bleicher advocates reining in post-diagnosis use of MRI, other experts feel there is need for more research.

"We don't really know what the endpoint is. We don't know how this really affects survival. We need larger studies to see the effect," said Dr. Debra L. Monticciolo, a professor of radiology at the Texas A&M Health Science Center College of Medicine, and vice chair of research in radiology and chief of breast imaging at Scott & White in Temple. "We're relatively new in using MRI with newly diagnosed cancer patients. . . . These studies need to develop over time. We're in the trial phase of using the technology in a way that maybe we're not used to."

Neither this nor other studies are yet enough to swing recommendations. "We need more research before we come up with a general recommendation," said Debbie Saslow, director of breast and gynecologic cancer at the American Cancer Society. "It's not a cut-and-dried issue."

More information

The National Cancer Institute has more on breast cancer and MRI.

SOURCES: Richard J. Bleicher, M.D., co-director, breast surgery fellowship, Fox Chase Cancer Center, Philadelphia; Debra L. Monticciolo, M.D., professor, radiology, Texas A&M Health Science Center College of Medicine, vice chair, research in radiology, and chief, breast imaging, Scott & White, Temple; Debbie Saslow, Ph.D., director, breast and gynecologic cancer, American Cancer Society, Atlanta; Sept. 6, 2008, presentation, American Society of Clinical Oncology Breast Cancer Symposium, Washington, D.C.

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