Magnetic seed versus skin tattoo localization of non-palpable breast lesions: a single institution cohort study

Objective The objective of this retrospective study was to investigate the accuracy and feasibility of magnetic seed compared to skin tattoo in preoperative localization of impalpable breast lesions in terms of accuracy of placement, re-excision and positive margins rates, and breast/surgical specimen volume ratio. Methods We retrospectively analyzed 77 patients who underwent breast conservative surgery in our center from November 2020 to November 2021, with previous localization with skin tattoo or magnetic seed. Results Thirty-seven magnetic seeds were placed in 36 patients (48.6%) and 40 skin tattoos were performed in the remaining cases (51.4%). The seeds were placed correctly at the two-view mammogram acquired after the insertion in 97.6% (36/37) of cases. With both methods, 100% of the index lesions were completely removed and found in the surgical specimen. The reported re-excision rate was 0% for both groups. A significant difference was observed in the volume of breast parenchyma removed between the two groups, inferior in the seed group ( p = 0.046), especially in case of voluminous breasts ( p = 0.003) and small lesions (dimension