Does preoperative MRI boost mastectomy rates?
Studies offer intriguing results
In the absence of any randomized clinical trial data, clinicians aren't exactly sure when it makes good sense to order magnetic resonance imaging (MRI) prior to breast cancer surgery and when it is more likely to offer little benefit. One of the biggest concerns is that because of its high sensitivity, MRI results may be driving more women to opt for mastectomy rather than lumpectomy, even though only a small number of lesions detected by MRI will turn out to be cancerous.
Single-center studies offer conflicting results regarding this issue. For example, in a not-yet-published retrospective review of the records of 481 breast cancer patients who underwent surgery over six years (2000 to 2006), researchers at the University of California, San Diego (UCSD) found that even though the use of MRI prior to breast cancer surgery has risen dramatically, the mastectomy rate at UCSD Medical Center remained stable. Further, investigators found that the lumpectomy negative margin rate increased (80%) among women who underwent pre-operative MRI versus those who did not undergo the imaging procedure (75%). The research was led by Christopher Comstock, MD, an associate clinical professor and the director of breast imaging at UCSD's Department of Radiology,
"The thing you have to be cautious about when embarking on preoperative MRI is that you don't delay their surgery or treatment by weeks and weeks," Comstock emphasizes. "The difference in time to surgery between a patient who had preoperative MRI and one who didn't [in our study] was only 12 calendar days, so if it is used appropriately, I think [preoperative MRI] is a benefit to most patients." Comstock acknowledges, however, that it is problematic that there is no data on the impact of preoperative MRI on reducing recurrence rates or mortality.
Other factors may be involved
While Comstock found no association between the use of preoperative MRI and mastectomy rates at his center, investigators at the Mayo clinic in Rochester, MN, did find that patients who undergo MRI prior to breast surgery are 10-15% more likely to opt for a mastectomy compared with patients who don't undergo MRI.
The study, which didn't consider surgical outcomes, looked at more than 5,400 women who had surgery for early-stage breast cancer at the Mayo Clinic between 1997 and 2006. The numbers are intriguing because mastectomy rates declined at the Mayo Clinic from 44% in 1997 to 30% in 2003, but then rose to 43% in 2006 — a period when the use of MRI also increased. Nonetheless, investigators can't be sure that the increase in mastectomies is related to the use of MRI.
There are multiple other factors that also can contribute to the increase in mastectomies," says Amy Degnim, MD, a coauthor of the study, which has not yet been published, and a breast surgeon at the Mayo Clinic. "One idea that has been proposed that I think can also have an impact on women choosing mastectomies is the availability and increased utilization of breast reconstruction," Degnim says. "Because we have good reconstruction techniques available and because more women are becoming aware of them, maybe they are more likely to indicate that they would rather have a mastectomy."
Degnim adds that the increased use of genetic testing for the BRCA mutation could be another factor driving the increase in mastectomies.
To pin down precisely why the women included in this analysis opted for MRIs or mastectomies will require individual chart reviews, and Degnim says that she and her colleagues are strongly considering such an investigation soon.
In the absence of any randomized clinical trial data, clinicians aren't exactly sure when it makes good sense to order magnetic resonance imaging (MRI) prior to breast cancer surgery and when it is more likely to offer little benefit.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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