AJR: Breast MR may rule out malignancy, surgery for some with high-risk lesions
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| Breast MRI Navigation software Source: Sentinelle Medical |
Most high-risk breast lesions are managed surgically, which is associated with increased cost, patient anxiety and scarring. Two previous small, retrospective studies hinted that MRI might inform surgical decision-making.
Anna Linda, MD, of the Institute of Diagnostic Radiology at Azienda Ospedaliero-Universitaria Santa Maria della Misericordia in Udine, Italy, and colleagues designed the current study to determine whether breast MRI may be employed to rule out malignancy in patients with high-risk lesions diagnosed at biopsy.
The study population was comprised of 166 patients with 169 high-risk lesions who presented between October 2004 and April 2010.
Lesions were biopsied via mammographic or ultrasound guidance, and women then underwent MRI and surgical excision, with MR data reviewed by two breast radiologists. Histologic findings based on surgical excision served as the reference standard.
According to the breast MRI analysis, 116 lesions were negative and 53 positive. Of the MR-positive lesions, 30.2 percent were determined to be malignant (true-positive) at surgical excision and 69.8 percent were benign (false-positive) at surgical excision.
Linda and colleagues reported overall sensitivity, specificity and positive and negative predictive values of MRI in the identification of malignancy as 72.7, 74.8, 30.2 and 94.8 percent, respectively.
Although the researchers concluded that breast MRI can be used to identify high-risk lesions with a low likelihood of upgrade to malignancy at surgical excision, they found variability among lesion types. “MRI had an unacceptably low negative predictive value for malignancy in patient with lobular neoplasia and atypical ductal hyperplasia (88 and 90 percent, respectively), corresponding to 12 and 10 percent false-negative rates.”
Linda and colleagues recommended against MRI to inform the decision-making process for lobular neoplasia and atypical ductal hyperplasia, adding that these lesions should be excised because of the high upgrade rate.
However, they suggested that women with papilloma without atypia and radial scar and normal MRI results may avoid surgical excision and undergo clinical and imaging follow-up. The researchers offered that six-month follow-up for two years with both conventional and MR imaging could suffice for this population.