A prospective, single-arm, multicentre clinical evaluation of a new localisation technique using non-radioactive Magseeds for surgery of clinically occult breast lesions.

Aim: To evaluate the safety, usefulness, and outcome of Magseed localisation for surgery of non-palpable breast lesions in a non-experimental setting.

Materials And Methods: An audit was undertaken of a prospectively maintained database of patients who had undergone breast surgery under Magseed guidance in two high-volume institutions in the UK. Patients were selected for Magseed localisation depending on service convenience. Wire localisations were used in other patients in accordance with previous normal practice. One hundred and thirty-nine Magseed localisaton procedures were performed between September 2017 and March 2019. Data were collected on age, body mass index, size, bra cup size, weight of specimen, surgery, histology, re-excision rate, and time and mode of insertion of seeds.

Results: A total of 137 patients had Magseed localisation with a total of 139 seeds. Sixteen patients had a diagnostic procedure and 121 had therapeutic surgery. The distribution of procedures were similar between the two institutes (n=63 and n=74). Mean age was 60 (range 28-81) years. The majority of seeds were placed under ultrasound guidance (n=112) and 25 lesions were targeted under stereo guidance. Mean size of the lesions was 15.2 (range 1-85) mm. The mean weight of the specimen was 75.5 (range 2-1,900) g. The mean body mass index was 30.56 (range 18.1-48.3). All Magseeds and index lesions were retrieved. The re-excision rate for patients who underwent therapeutic surgery was 14.8% (n=18).

Conclusion: The Magseed localisation technique of non-palpable breast lesions is a safe, easy procedure, and comes with the advantage of better utilisation of theatre and radiology resources. The re-excision rate in this series is lower than the national average.