MRI-guided breast biopsy: outcomes and effect on patient management

Abstract

Introduction: The purpose of this study was to correlate the pathology results of MRI-guided breast biopsies at our institution with MRI findings and patient clinical history characteristics. The effect of MRI-guided breast biopsies on surgical management in patients with a new diagnosis of breast cancer was also assessed.

Patients and methods: In this Health Insurance Portability and Accountability Act-compliant study we retrospectively reviewed all MRI-guided breast biopsies performed from March 2006 to May 2012. Clinical history, MRI features, and pathology outcomes were reviewed. In patients who underwent breast MRI to evaluate extent of disease, any change in surgical management resulting from the MRI-guided biopsy was recorded. Statistical analysis included binary logistic regression and independent Student t test.

Results: Two-hundred fifteen lesions in 168 patients were included, of which 23 (10.7%) were malignant, 43 (20%) were high-risk, and 149 (69.3%) were benign. No clinical characteristic was associated with malignancy in our cohort. MRI features associated with malignancy were: larger size (mean 2.6 cm vs. 1.3 cm; P = .046), washout kinetics (18% malignancy rate; P = .02), and marked background parenchymal enhancement (40% malignancy rate; P < .001-.03). Nineteen (28%) of the 67 patients with a new diagnosis of breast cancer who underwent MRI-guided breast biopsy had a change in surgical management based on the biopsy result.

Conclusion: Malignancy rate was associated with lesion size, washout kinetics, and marked background enhancement of the breast parenchyma but was not associated with any clinical history characteristics. Preoperative MRI-guided breast biopsies changed surgical management in 28% of women with a new diagnosis of breast cancer.

Keywords: Breast MRI; Core biopsy; MRI-guided biopsy; Pre-operative breast MRI.

Figure 1. Flowchart of Lesion Outcomes

215 lesions underwent MRI-guided biopsy at our institution between 3/2006 and 5/2012 (200 underwent MRI-guided core biopsy and 15 underwent MRI-guided localization or clip placement with surgical biopsy). The malignancy rate at core biopsy was 8.0%. The malignancy rate of MRI-guided localizations was 20%. The final malignancy rate after surgery was 10.7%.

Figure 2. Box plot demonstrating lesion size among benign and malignant lesions

Larger lesion size was significantly associated with malignant pathology outcome, although there was a considerable overlap of lesion size among benign and malignant lesions.

Figure 3. Change in Surgical Plan as a Result of MRI-Guided Biopsy

19/67 (28%) of patients with a new diagnosis of breast cancer undergoing MRI-guided biopsy had a change in their surgical plan as a result of the biopsy. (NOTE: figure 3 is intended for color print)

Figure 4. Example of MRI-guided breast biopsy changing the surgical plan in a patient with a new diagnosis of breast cancer

(A) axial subtraction image and (B) axial T1-weighted image with dynamic contrast enhanced kinetics in a 45 year old female with biopsy-proven right breast invasive ductal carcinoma (IDC, white arrows) who planned for lumpectomy prior to breast MRI. MRI demonstrated two suspicious foci in the ipsilateral breast (yellow arrows), up to 8 cm from the known cancer. MRI-guided breast biopsy of the posterior focus yielded IDC, and the patient subsequently underwent a mastectomy. (NOTE: Figure 4 is intended for color print)

Figure 5. Example of MRI-guided breast biopsy changing the surgical plan in a patient with a new diagnosis of breast cancer

(A) Axial subtraction image in a 52 year old female with biopsy-proven right breast invasive lobular carcinoma (ILC, white arrow). (B) Axial subtraction image and (C) axial T1-weighted with dynamic contrast enhanced kinetics MRI also demonstrated a suspicious mass in the contralateral (left) breast with washout kinetics (orange arrow). The left breast mass underwent MRI-guided breast biopsy, yielding invasive ductal carcinoma (IDC). The patient subsequently underwent bilateral lumpectomies. (NOTE: Figure 5 is intended for color print)