Placement of radiofrequency identification tags: Is there an optimal tag-to-target distance?

Radiofrequency identification (RFID) tag localization (TL) is a method of localizing non-palpable breast lesions. The purpose of our study was to evaluate the association between RFID tag-to-target distance, margin positivity rates, and surgical specimen sizes.

A retrospective cohort analysis was performed on consecutive TL excisional biopsies and lumpectomies performed between 2018 and 2021. Associations between the longest distance between tag and target, positive margins, and the surgical specimen volume were analyzed using univariate and multivariate analyses.

Four hundred fifty-six non-palpable breast lesions in 445 patients were included, with a median tag-to-target distance of 4.5 mm and a positive margin rate of 15.1%. For lumpectomies, there was no significant association between tag-to-target distance and margin positivity rate, nor surgical specimen size on multivariate analysis. The only significant predictor of positive lumpectomy margins was ductal carcinoma in situ (DCIS) on final pathology (p < 0.001). Significant predictors of increased lumpectomy specimen volume included operating surgeon (p = 0.005) and body mass index (BMI) (p < 0.001). For excisional biopsies, tag-to-target distances ≥ 10 mm were associated with larger surgical specimen size on univariate analysis (OR: 2.961, p = 0.04). However, when confounding variables were adjusted for, there was no significant association between tag-to-target distance ≥ 10 mm and surgical specimen size (p = 0.12). Factors predictive of increased excisional biopsy specimen volume were surgeon (OR: 4.762, p = 0.03), BMI (OR: 1.164, p = 0.001), and age (OR: 1.062, p = 0.007).

There was no evidence of a significant association between tag-to-target distance and margin positivity rate or surgical specimen size for lumpectomies or excisional biopsies.

Question Currently, there exists little guidance for breast surgeons and radiologists regarding the ideal localization tag-to-target distance prior to breast-conserving surgery. Findings With communication between radiologists and surgeons, increased tag-to-target distance had no significant effect on surgical outcomes. Clinical relevance This data provides guidance regarding the need for additional localization after distant placement of radiofrequency-identification tags. While cases should be assessed individually to determine the need for additional localization, these data better inform multidisciplinary decision-making regarding TL.