Preoperative Magnetic Seed Versus Wire‐Guided Localization in the Treatment of Nonpalpable Breast Cancer: A Retrospective Observational Study at a Tertiary Care Center

<b>Background:</b> Breast cancer screening and effective neoadjuvant treatments have increased surgeries for nonpalpable tumors, often requiring preoperative localization. The wire-guided method, performed on the same day as surgery, has limitations, prompting interest in wire-free alternatives like magnetic seed devices. <b>Methods:</b> A retrospective single-center study (November 2020-March 2024) compared magnetic seed and wire-guided localization in 558 patients. The primary aim was to assess localization and retrieval success, resection margins, and reoperation rates. Secondary endpoints included the interval between localization and surgery, operative time, incision site selection, and volume excised. <b>Results:</b> Among 558 patients, 188 underwent magnetic seed and 370 wire-guided localizations. Both groups were similar in BMI, breast size, and lesion characteristics. Complications in the wire-guided group included device migration (0.5%) and hematoma (1.3%). Success rates were comparable (98.9% vs. 99.7%), as were positive margins (5.3% vs. 6.7%) and reoperation rates (6.9% vs. 7.8%). Excised volume was significantly lower in the magnetic seed group (24.2 [range 6.5-48.0 cm³] vs. 41.5 cm³ [range 16.0-68.0 cm³], <i>p</i> < 0.001). The magnetic seed group had an average localization-to-surgery interval of 1 day (range 0-160 days). <b>Conclusions:</b> Magnetic seed localization is as safe and effective as wire-guided localization, with comparable success rates and resection margins adequacy. Its primary advantage is scheduling flexibility, offering a longer interval between localization and surgery.