Imaging outcomes: Preop breast MR does not cut reoperation rate
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Current practice guidelines from the American College of Radiology and American Society of Breast Surgeons suggest breast MR for several indications among women newly diagnosed with breast cancer and support its use among patients with breast cancer who may have difficulties with conventional imaging, such as those with invasive lobular carcinoma or dense breasts.
“Implicit in the use of preoperative MR imaging is improved surgical planning, leading to a reduction in re-excision surgery and to a more precise determination of the need for mastectomy because of multicentric disease,” wrote Joseph J. Weber, MD, from the department of surgery at East Carolina University in Greenville, N.C., and colleagues.
However, the use of breast MR for preoperative staging remains controversial, primarily due to its cost, high false-positive rate and uncertain effect on outcomes, such as ipsilateral recurrence or reoperation rates, according to the researchers.
Weber and colleagues designed a retrospective cohort study of all women with newly diagnosed breast cancer undergoing primary surgical treatment by a single surgeon at East Carolina University between Jan. 1, 2006, and Dec. 31, 2010.
Among the 313 women, 120 underwent preoperative breast MR. The mean age of women who underwent MR was significantly younger than those who did not (53.6 years vs. 59.5 years). Women in the MR group were more often of non-Hispanic white race/ethnicity (61.7 percent vs. 52.3 percent) and more likely had heterogeneously dense or very dense breasts (68.4 percent vs. 22.3 percent).
However, the type of surgery was similar in both groups, according to the researchers. Reoperation rates also were similar, at 19.1 percent in the MR group vs. 17.6 percent in the no MR group.
“Our findings suggest that, even in a well-defined subset of patients, MR imaging fails to improve rates of reoperation.”
Furthermore, the researchers noted that 25.5 percent of the women who underwent mastectomy in the study had a pathologically avoidable mastectomy, which confirms the risk of false-positive interpretations of MR images.
Weber and colleagues concluded by stressing that the results do not support even the selective use of preoperative MR to reduce the reoperation rate in operable breast cancer.