Radioactive seed localization for nonpalpable breast lesions: review of 1,000 consecutive procedures at a single institution.

INTRODUCTION: Radioactive seed localization (RSL) is an alternative to wire localization for nonpalpable breast lesions, with reported lower rates of positive surgical margins.

METHODS: A retrospective review of all consecutive RSL procedures performed at a single institution from 01/2003 through 10/2010 was conducted.

RESULTS: One thousand RSL breast procedures were performed in 978 patients. Indications for RSL included invasive carcinoma (52%), in situ carcinoma (22%), atypical hyperplasia (11%), and suspicious percutaneous biopsy findings (15%). A total of 1,148 seeds were deployed using image guidance, with 76% placed ≥1 day before surgery. Most procedures (86%) utilized one seed. A negative margin was achieved at the first operation in 97% of patients with invasive carcinoma and 97% of patients with ductal carcinoma in situ (DCIS). An additional 9% of patients with invasive carcinoma and 19% of patients with DCIS had close (≤2 mm) margins, and underwent re-excision. Sentinel lymph node biopsy was successfully performed in 99.8% of cases. Adverse events included 3 seeds (0.3%) not deployed correctly on first attempt and 30 seeds (2.6%) displaced from the breast specimen during excision of the targeted lesion. All seeds were successfully retrieved, with no radiation safety concerns. Local recurrence rates were 0.9% for invasive breast cancer and 3% for DCIS after mean follow-up of 33 months. There was no evidence of a learning curve.

CONCLUSIONS: RSL is a safe, effective procedure that is easy to learn, with a low incidence of positive/close margins. RSL should be considered as the method of choice for localization of nonpalpable breast lesions.