Rate of high-risk lesions on MRI-guided breast biopsy at high end of previous estimates

MRI-guided breast biopsy yielded high-risk lesions in 21.5 percent of cases, according to a study published in the September issue of the American Journal of Roentgenology.

“Our study found high-risk lesions … at the higher end of the range previously reported (three to 21percent),” wrote lead author Ana P. Lourenco, MD, of Brown University’s Warren Alpert Medical School in Providence, R.I., and colleagues.

The retrospective study reviewed 446 MRI-guided breast biopsies from January 2006 through December 2010 to determine the underestimation rate of high-risk lesions. The researchers examined the size and type of lesions and pathology results. The biopsies were performed with a 9-gauge vacuum-assisted device. 

Results showed an underestimation risk of 23.2 percent for all high-risk lesions combined. This was within the range found by other studies, according to the authors. Of the 446 MRI-guided biopsies, 96 (21.5 percent) were high-risk lesions. Forty-two of 96 lesions were masses, and 54 showed nonmass enhancement. Twenty of 96 lesions were ADH, nine were lobular neoplasia, 27 were papillary lesions, 20 were radial scar, and 20 were other atypias.

Sixteen of 69 (23.2 percent) lesions were upgraded to malignancy; 11 of the 16 (68.8 percent) were upgraded to ductal carcinoma in situ and five (31.2 percent) were upgraded to invasive carcinoma, the authors said.

The rate of underestimation was highest for ADH (31.6 percent) and lowest for papillary lesions (5.9 percent).

The study had the highest number of papillary lesions and radial scars reported in studies evaluating MRI-detected high-risk lesions. Some studies of high-risk lesions have reported upgrade rates for papillary lesions ranging from zero to 29 percent.

“Our relatively low upgrade rate for papillary lesions raises questions about the need for surgical excision in patients with this result at needle biopsy,” commented Lourenco and colleagues.

Nearly 90 percent of of the examinations in the study were performed for either newly diagnosed breast cancer (46.9 percent) or for high-risk screening (42.7 percent). Of the breast MRI examinations, 80-83 percent were done for newly diagnosed breast cancer and high-risk screening in previous studies, they noted.