Magseed localisation for surgical excision of non-palpable breast lesions and targeted axillary lymph node dissection

Abstract Introduction Magseed localisation is increasingly popular in breast surgery due to its ability to be inserted any time pre-operatively without signal decay, lack of ionising radiation, ease of operator use, and low rates of migration. We aim to prospectively audit this technique for excisions of non-palpable breast lesions and axillary lymph nodes in terms of outcome and complications. Method Prospective data was collected from June 2022 to December 2024 in 500 patients who had Magseed localisation of breast and axillary lesions in a tertiary Australian metropolitan hospital. Result A total of 550 Magseeds were used. The majority had a single breast lesion localised with a single Magseed (n=468), with multiple Magseeds for multiple lesions in 14 cases. Bracketing was used in 20 cases. Wide local excisions were performed in 372 cases (n=335 level 1 oncoplasty, n=37 level 2 oncoplasty), and there were 135 excisional biopsies. Magseed-guided targeted axillary dissection was performed for 13 patients. Pre-operative biopsies included invasive cancer (n=297), DCIS only (n=70), and B3 pathologies (n=162). Median time from insertion to surgery was 7 days, with 36 placed on the day of surgery. Post-operative complications, including infection and haematoma, were the same rates as non-Magseed breast surgery population, with no complications relating to the Magseed recorded. Re-excision rate for positive margins was 21.7% (n=81). Discussion Magseed localisation in breast surgery is a safe and reliable technique. It can be inserted days to months before surgery, proved to be accurate in locating non-palpable breast lesions, and shows low rates of surgical complications.