Utilization of Multiple I-125 Radioactive Seeds in the Same Breast is Safe and Feasible: A Multi-institutional Experience.

Objective: Radioactive seed localization has been shown to be a reliable and safe alternative to wire localization in breast surgery, but little is known about the use of multiple localization seeds. This study evaluated the utilization of multiple seeds in the same breast.

Methods: All patients who underwent localization of breast lesions using multiple I-125 seeds at three Mayo Clinic sites between January 2003 and June 2014 were included.

Results: A total of 461 operations were performed during an 11.5-year study period. The indications for multiple seed placement in the same breast included multiple lesions (n = 258), bracketing (n = 110), multiple lesions and bracketing (n = 67), and a second inserted for more precise localization (n = 26). Among patients with bracketing seeds, the mean distance between seeds was 45 (range 8-110) mm. Removal of the targeted lesion was successful in all cases; 96% of bracketed lesions were removed as a single specimen, and a 98% retrieval rate within the first specimen was obtained. In total 108 of 382 (28%) patients had close or positive margin resulting in a second procedure and 60 of 177 (34%) patients with bracketing procedures underwent reexcision of positive margins or culminated in a mastectomy. Routine intraoperative frozen section analysis was associated with a lower reoperation rate compared with a selective approach to intraoperative margin assessment.

Conclusions: The use of multiple radioactive seeds for localizing multiple lesions in the same breast or bracketing lesions is feasible and safe. Because of the extent of disease, a substantial percentage of these patients require margin reexcision or conversion to mastectomy.