Cancellation of MR imaging-guided breast biopsy due to lesion nonvisualization: frequency and follow-up.

PURPOSE: To determine the rate of canceled magnetic resonance (MR) imaging-guided breast biopsies due to nonvisualization of the lesion and to assess associated features and outcome data for these cases.
MATERIALS AND METHODS: With the approval of the institutional review board, a HIPAA-compliant retrospective review, in which the requirement for informed consent was waived, was performed for 907 patients scheduled for MR imaging-guided breast biopsy from 2004 to 2008. In 70 patients, MR imaging biopsy was canceled due to lesion nonvisualization. Medical records and imaging studies were reviewed to identify patient, parenchymal, lesion features and outcome data. Statistical analysis was performed with the Fisher exact test. The 95% confidence interval (CI) was calculated.
RESULTS: Cancellation of MR-guided biopsy due to lesion nonvisualization occurred in 8% (70 of 907) of patients and in 8% (74 of 911) of lesions. Factors associated with a significantly higher cancellation rate included marked and moderate versus mild and minimal background parenchymal enhancement (38 of 316 [12%] vs 32 of 591 [5%], P = .001), extremely and heterogeneously dense versus scattered fibroglandular densities and fatty parenchymal volume (64 of 712 [9%] vs six of 195 [3%], P = .006), and lesions 1 cm or less in size (52 of 520 [10%] vs 22 of 391 [6%], P = .02).The rate of cancellation per year was highest in the first year, with a decrease in subsequent years (14 of 102 [14%] vs 56 of 805 [7%], P = .025). A significantly lower rate was found in women with synchronous breast cancer (nine of 240 [4%] vs 61 of 667 [9%], P = .007), and a significantly higher rate was found in women with a history of cancer (35 of 315 [11%] vs 35 of 592 [6%], P = .01). Among 58 women who had MR imaging follow-up, no cancers were identified. Among three women who underwent mastectomy after cancellation, one had ductal carcinoma in situ in the same quadrant as the MR-depicted lesion. The cancer detection rate among 61 women who underwent either MR imaging or pathologic follow-up was 2% (one of 61) (95% CI: 0.4%, 9%).
CONCLUSION: MR imaging-guided breast biopsy was canceled due to lesion nonvisualization in 8% of the patients. Although the cancer detection rate among the lesions for which biopsy was canceled is low (95% CI: 0%, 9%), short-term follow-up MR imaging is prudent. © RSNA, 2011.