Radiofrequency as a method of localizing impalpable breast lesions.

Background: The incidence of early stage breast cancer has risen as a result of increased detection of non-palpable tumors through the implementation of screening programs and greater public awareness. Performing breast-conserving surgery can be challenging due to the need for accurate localization of non-palpable breast lesions, particularly given the logistical difficulties associated with wire localization. After implementing a new technique for localizing non-palpable breast lesions (LOCalizerTM Radiofrequency identification TAG-Hologic®), a radiofrequency identification tag localization device manufactured by Hologic, Inc. in Marlborough, MA, was launched in 2017, our objective was to investigate its impact on surgical outcomes, whether there was an increase in re-excision rates for positive margins and whether the attainment of clear margins was dependent on the exact positioning of the RFID device.

Method: A single-center single-arm interventional study, data were gathered both in a forward-looking manner for 1 year (prospectively) and by looking back at past records for 1 year (retrospectively) for a total period of two years. Individuals who were diagnosed with non-palpable breast lesions, as confirmed by histological analysis, or invasive breast cancer and who were scheduled to undergo breast-conserving surgery were eligible for inclusion in the study. The RFID (Radiofrequency Identification) method was used to localize the lesions prior to surgery. Either with a mammogram or ultrasound scan position of the Tag was recorded, including the distance of the lesion from the center of the lesion and the lesion depth from the skin in millimeters. The rate of re-excision was documented and examined in relation to the parameters mentioned above.

Results: Two hundred and twenty RFID Tags were inserted in two hundred and seventeen (three patient had bilateral tags insertion), patients aged between 30 and 85 had a localizer Tag inserted between Oct 2020 and Oct 2022. Three patients had non-palpable breast lesions in both breasts. Fourteen were inserted under stereotactic guidance and two hundred and six under ultrasound guidance. Ten patients subsequently had wire insertion also due to Tag position. Of 210 procedures, RFIF Tags within the lesion was seen in hundred and sixty patients (76.19 %). An additional 50 procedures were performed using the RFID Tag system, which were not directly related to the lesion but were deemed appropriate to proceed with. Out of a total of 220 procedures, positive margins were observed in 38 cases (17.27 %). Among these cases, eleven (28.94 %) involved the use of the RFID Tag system, not within the lesion but adjacent to it (within 15 mm surrounding the lesion).

Conclusion: RFID is a good alternative to wire localization of non-palpable breast lesions. Re-excision rates are higher in patients with Tag outside the lesion compared to those with Tag within the lesion.