SAN FRANCISCO—For clinicians, MRI may offer a more in-depth view than mammography for planning surgery and screening for contralateral breast cancers, but does use of MRI actually benefit patients?

"It seems intuitively obvious that MRI does help us, and in our heart of hearts, we think it probably does, but there is no proof," Kimberly Van Zee, MD, a surgical oncologist at Memorial Sloan-Kettering Cancer Center, said at a "current controversies" session of the 2007 ASCO breast cancer symposium.

"Over the last 10 years, the technology has developed tremendously," she said. "We're seeing remarkable, beautiful detail. It's almost seductive. We think 'how can it be bad to know all this good information?' It's intuitively obvious, but there are no data."

Dr. Van Zee also pointed to a possible increase in mastectomy rates with the use of breast MRI, adding her voice to those of other skeptics who say MRI may raise the mastectomy rate unnecessarily.

Retrospective studies

There are retrospective studies that hint at benefit of preoperative MRI for patients diagnosed with breast cancer, including Fischer et al (Eur Radiol 14:1725-1731, 2004).

The Fischer study showed a significantly lower local recurrence rate at 40 months post-treatment in women who underwent preoperative MRI, compared with those who did not (1.2% vs 6.8%). Contralateral breast cancer rates during follow-up were also significantly lower (1.7% vs 4%).

However, it remains unclear whether the lower local recurrence rate in this study was actually a result of the preoperative MRI staging, since, Dr. Van Zee said, the cancers of the study participants undergoing MRI were of a lower stage than those of the women who did not have an MRI.