Ultrasound-guided localization with magnetic seeds effective for localizing small non-palpable breast lesions

"Both surgeons and radiologists agreed that the technology was intuitive to use and could be widely applied in pre-operative localization in breast units," the researchers wrote in their study.

A significant proportion of breast cancer detected at mammographic screening are often small and non-palpable. To avoid excessive tissue removal, there is a need to precisely localize the non-palpable breast cancers before treatment. Wire localization has been the gold standard but researchers have begun experimenting with non-wired methods in recent years. These include magnetic seeds, radiofrequency identification (RFID) tags, radar reflectors, and radioactive seeds.

Catherine Depretto, Fondazione IRCCS Istituto Nazionale Tumori di Milano, Via Giacomo, Milan, Italy, and colleagues aimed to evaluate the performance of pre-operative magnetic seed localization of non-palpable breast lesions on a large scale.

For this purpose, the researchers prospectively collected data on all patients undergoing image-guided magnetic seed localization from 2019 to 2022. They analyzed the type of surgery, histological results, and imaging findings.

The primary outcome of the study was determined as the successful localization rate. Secondary outcomes included the ease of percutaneous positioning, successful placement rate, reintervention rate, and procedural complications.

The authors reported the following findings:

· A total of 1123 magnetic seeds were placed in 1084 patients by four radiologists under ultrasound (1053) or stereotactic (70) guidance.

· All seeds were detectable transcutaneously in all breast sizes and at all depths by seven surgeons with a success rate of 100%. 97,5% of the seeds were correctly placed into the target lesions (only 2,5% were dislocated).

· All radiologists have shown good compliance during the procedure, and there were no complications or safety issues.

· The re-operation rate was 5,1 %.

According to the authors, "this is the single-centre study with the largest cohort worldwide."

They added, "large size of the patient cohort allows us to add more evidence that image-guided localization with magnetic seeds is a safe, easy, effective, and reliable method for localizing non-palpable breast lesions."

"Consensus between surgeons and radiologists in our study highlighted the intuitive nature of this technology."

"Magnetic seed localization presents a promising avenue for widespread adoption in breast units," they concluded.

Reference:

The study titled, "Magnetic localization of breast lesions: a large-scale European evaluation in a National Cancer Institute," was published in Clinical Breast Cancer.

DOI: https://doi.org/10.1016/j.clbc.2023.08.004