Initial Experience Using Magseed for Breast Lesion Localization Compared With Wire-Guided Localization: Analysis of Volume and Margin Clearance Rates.

BACKGROUND: Detection of nonpalpable lesions requiring surgical intervention has increased during the past several decades. Techniques have evolved to help surgeons locate lesions in the operating room. Disadvantages of wire localization has led to the use of new approaches for surgical guidance. Magnetic seeds have been suggested to improve workflow and cosmetic result. METHODS: This retrospective cohort study analyzed consecutive patients undergoing lumpectomy or excisional biopsy with the guidance of wire localization or magnetic seeds. The optimal and total resected volumes were calculated from pathology records, and the calculated resection volumes were compared by localization approach. Margin positivity and need for reoperation were reviewed and compared. RESULTS: Each group included 148 patients. The majority were treated with lumpectomy and did not undergo preoperative chemotherapy. The operative characteristics did not vary by group. Considering only lumpectomy cases, total volume resected (13.7 vs. 17.1; p = 0.003) and calculated resection ratios (1.8 vs. 2.5; p = 0.02) were significantly lower in the magnetic seed group. The rates of positive margins (10% vs. 14%) and reoperation (12.8% vs. 17.3%) were non-significantly lower than in the wire localization cases. CONCLUSIONS: Magnetic seeds were successfully used for lesion localization in this cohort. Pathologic examination of specimens suggested that the surgeons were able to remove closer to optimal volumes of tissue than those using wire-guided intervention. Removal of less tissue did not result in higher rates of margin positivity or a need for re-intervention to achieve negative margin status. Magnetic seeds are a feasible and non-inferior approach that overcomes many drawbacks of other localization methods.

Molecular Breast Imaging in Breast Cancer Screening and Problem Solving.

In the United States, legislative actions in over 28 states require radiologists to notify women who undergo breast screening mammography of their breast density. This has led to increased public interest in supplemental screening, but radiologists have not come to a consensus on a supplemental screening modality. In choosing between the most common options, whole-breast ultrasonography (US) and magnetic resonance (MR) imaging, one must weigh the benefits and drawbacks of each modality, as increased cancer detection may be accompanied by increased examination costs and biopsy rates. There has been recent interest in molecular breast imaging (MBI) for supplemental screening because of its high sensitivity, as well as its high specificity. This article describes how MBI fits into clinical practice alongside digital breast tomosynthesis (DBT), targeted US, and MR imaging. The authors describe their approach to breast cancer screening, which uses DBT as the primary imaging modality. DBT is complemented by automated density calculations and supplemented with functional imaging techniques, including MR imaging or MBI, for women with dense breasts. An algorithm based on the patient's breast cancer risk is used to determine if either MR imaging or MBI for supplemental screening is appropriate. MBI is also used as a problem-solving tool for the evaluation of clinical indications following complex mammography or US, or for unexplained physical findings. This article describes aspects related to implementing MBI in clinical practice, including the clinical workflow, patient management, radioactive tracer administration, and procedure reimbursement. © RSNA, 2017.

Supplemental Breast Cancer Screening With Molecular Breast Imaging for Women With Dense Breast Tissue.

OBJECTIVE: Molecular breast imaging was implemented in routine clinical practice at a large community-based breast imaging center. The aim of this study was to retrospectively assess the clinical performance of molecular breast imaging as a supplementary screening tool for women with dense breast tissue. MATERIALS AND METHODS: Women with dense breasts and negative mammography results who subsequently underwent screening with 300 MBq (8 mCi) (99m)Tc-sestamibi molecular breast imaging were retrospectively analyzed. Outcome measures included cancer detection rate, recall rate, biopsy rate, and positive predictive values (PPVs). RESULTS: Molecular breast imaging screening of 1696 women in this study resulted in the detection of 13 mammographically occult malignancies, of which 11 were invasive, one was node positive, and one had unknown node positivity. The lesion size ranged from 0.6 to 2.4 cm, with a mean of 1.1 cm. The incremental cancer detection rate was 7.7‰ (95% CI, 4.5-13.1‰), the recall rate was 8.4% (95% CI, 7.2-9.8%), and the biopsy rate was 3.7% (95% CI, 2.9%-4.7%). The PPV for recall (PPV 1) was 9.1% (95% CI, 5.4-15.0%), and the PPV for biopsy (PPV 3) was 19.4% (95% CI, 11.4-30.9%). CONCLUSION: When incorporated into a community-based clinical practice environment, molecular breast imaging yielded a high incremental cancer detection rate of 7.7‰ at an acceptable radiation dose. These results show the utility of molecular breast imaging as a supplementary screening tool to mammography for women with dense breasts.