Breast MRI may have a role in evaluation of newly diagnosed breast cancers

May 22 2007

Among women who are newly diagnosed with breast cancer, magnetic resonance imaging (MRI) of the breast appears helpful in determining surgical treatment, according to a report in the May issue of Archives of Surgery.

Women who have been newly diagnosed with breast cancer are at risk of having another, hidden tumor in the same or opposite breast, according to background information in the article. If these additional tumors are detected before surgery to remove the initially diagnosed tumor, the plan for surgical management of the disease can be altered. For instance, if additional cancer is found in the same breast, a surgeon can perform a mastectomy (removal of the whole breast) instead of a lumpectomy (removal of a part of the breast) or remove a larger amount of tissue during a lumpectomy. If cancer is detected in the other breast, surgery can be done on both breasts at once. "However, the impact of routine MRI on the surgical management of new, biopsy-proven breast cancers remains unclear," the authors write.

Karl Y. Bilimoria, M.D., and colleagues at the Feinberg School of Medicine, Northwestern University, Chicago, assessed 155 women with breast cancer newly diagnosed by mammogram, ultrasound and needle biopsy (testing of a small amount of tissue). The women, who were diagnosed between April 2005 and April 2006, went to a single surgeon who performed an evaluation and developed a plan for the surgical management of the disease. After this consultation, MRI was performed on both breasts. If the MRI detected new tumors that were found to be malignant or suspicious after a biopsy, patients went back to the surgeon for a re-evaluation of the surgical plan.

Breast MRI detected a total of 124 additional suspicious areas in 73 patients. "Breast MRI altered the surgical management of patients with newly diagnosed breast cancer in 36 (23.2 percent) of 155 patients," the authors write. This included 10 patients who had a mastectomy instead of lumpectomy, 21 women whose lumpectomy removed more tissue than originally planned, and five patients who had surgery on both breasts.

Following surgery, the researchers compared the actual appearance of the cancer to the original mammogram or ultrasound and also to the MRI. The change in surgical management was considered beneficial if pathological findings matched the MRI more closely than they matched mammography or ultrasonography. "Of the 36 women who had a change in surgical management based on MRI findings, 15 were found to have a beneficial change when MRI findings were confirmed on the final pathologic report," the authors write. The change was determined to be beneficial in eight women whose lumpectomy was converted to a mastectomy, 10 patients who received a larger lumpectomy and two patients who had surgery on both breasts.

"Additional malignancies are uncovered in one patient for every 10 who undergo MRI," the authors conclude. "These data suggest that breast MRI may have a role in the staging evaluation of newly diagnosed breast cancers."

http://archsurg.ama-assn.org/