Outcome of high-risk lesions at MRI-guided 9-gauge vacuum- assisted breast biopsy.

OBJECTIVE

The purposes of this study were to determine the frequency of underestimation of high-risk lesions at MRI-guided 9-gauge vacuum-assisted breast biopsy and to determine the imaging and demographic characteristics predictive of lesion upgrade after surgery.

MATERIALS AND METHODS

We retrospectively reviewed consecutively detected lesions that were found only at MRI and biopsied under MRI guidance from May 2007 to April 2012. Imaging indications, imaging features, and histologic findings were reviewed. The Fisher exact test was used to assess the association between characteristics and lesion upgrade. Patients lost to follow-up or who underwent mastectomy were excluded, making the final study cohort 140 women with 151 high-risk lesions, 147 of which were excised.

RESULTS

A database search yielded the records of 1145 lesions in 1003 women. Biopsy yielded 252 (22.0%) malignant tumors, 184 (16.1%) high-risk lesions, and 709 (61.9%) benign lesions. Thirty of the 147 (20.4%) excised high-risk lesions were upgraded to malignancy. The upgrade rate was highest for atypical ductal hyperplasia, lobular carcinoma in situ, and radial scar. No imaging features were predictive of upgrade. However, there was a significantly higher risk that a high-risk lesion would be upgraded to malignancy if the current MRI-detected high-risk lesion was in the same breast as a malignant tumor previously identified in the remote history, a recently diagnosed malignant tumor, or a high-risk lesion previously identified in the remote history (p = 0.0001). The upgrade rate was significantly higher for women with a personal cancer history than for other indications combined (p = 0.0114).

CONCLUSION

The rate of underestimation of malignancy in our series was 20%. No specific imaging features were seen in upgraded cases. Surgical excision is recommended for high-risk lesions found at MRI biopsy and may be particularly warranted for women with a personal history of breast cancer.