MRI scans and mastectomy

MRI breast scans are associated with more mastectomies. That is the conclusion from a study by Mayo Clinic researchers in the USA. They have found that after an earlier, seven-year decline, there has been a sharp rise in the number of whole-breast mastectomies for early-stage breast cancer carried out at the Rochester clinic during the last three years.

The research does not, of course, suggest that MRI scans are in anyway causing breast cancer, rather they may simply be providing an earlier opportunity for patients to undergo interventionist therapy for a potentially fatal disease well before metastasis might occur or because of counselling following genetic profiling. The researchers say that further research is needed to elucidate the exact underlying reasons for the change in mastectomy numbers.

Study co-author, Rajini Katipamula explains: "We found that if a woman undergoes an MRI before surgery, she is about 10 percent to 15 percent more likely to have a mastectomy, compared to women who did not undergo MRI," he says.

Katipamula and colleagues presented their results to the 44th Annual Meeting of the American Society of Clinical Oncology (ASCO) on May 31. The team, led by Matthew Goetz, who is assistant professor of oncology at Mayo Clinic, evaluated mastectomy trends by year and by use of preoperative breast MRI among more than 5,000 women who had surgery for early-stage breast cancer at the Mayo Clinic between 1997 and 2006.

The team found that the mastectomy rate declined from 44% in 1997 to 30% in 2003, but then had risen again to 43% in 2006. During this time, the percentage of women who had MRI breast scans more than doubled, from 11% in 2003 to 23% in 2006. The mastectomy rate was significantly higher in women who had a presurgical MRI (52%) compared with women who did not have the test and chose breast removal (41%).

"Our study is the largest to examine the association between MRI and mastectomy rates at a single institution and may reflect national trends," says Goetz. He adds that MRI is such a powerful technique that it can detect cancerous and non-cancerous breast lesions easily. This diagnostic power may underlie why a woman, together with her physician, may choose total breast removal rather than lumpectomy, even though both procedures may have similar proven outcomes and survival rates.

"What we don't know from this study is whether the higher rate of mastectomy observed in our patients undergoing MRI is related to the detection of additional disease, or whether the uncertainty raised by MRI leads to greater anxiety for the patient and physician, thus leading patients and physicians to choose mastectomy over lumpectomy," explains Goetz.

Mayo breast surgeon Amy Degnim emphasises that although MRI seems to be associated with a higher rate of mastectomy, this is not necessarily an instance of cause-and-effect. "More investigation at an individual level is needed to understand better how MRI may impact personal choices for breast cancer surgery," she says.

Goetz points out that mastectomy rates overall have increased even in women who did not undergo MRI. This suggests that other factors such as social acceptance of mastectomy, or even simply greater awareness of the potential for lethal secondary cancers, as well as genetic profiling and insights from familiy history, may be playing a role in the decision-making process.

"In the past ten years, we have observed numerous changes in the preoperative management of patients with breast cancer," Goetz adds, "In addition to new imaging modalities such as MRI, more women are familiar with the role of genetics as a risk factor for breast cancer, and some of our patients are undergoing testing. Additionally, there has been improved access to better breast reconstruction methods."

The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.