Occult breast lesion localization plus sentinel node biopsy (SNOLL): Experience with 959 patients at the European Institute of Oncology

Background: Non-palpable breast lesions are diagnosed frequently posing the problem of localization and removal. When such lesions are malignant, axillary node status must be determined. We report our experience using radio-guided occult lesion localization (ROLL) for locating and removing non-palpable breast lesions together with sentinel node biopsy (SNB) to assess axillary status. We call the technique SNOLL. Methods: From March 1997 to April 2004, 1046 consecutive patients presented suspicious non-palpable breast lesions and were programmed for conservative surgery and SNB. In 87 patients intraoperative histological examination revealed a benign lesion and SNB was not performed. The remaining 959 patients, with cytologically or histologically proven cancer, underwent SNOLL with immobile radiotracer injected under mammographic or ultrasound (US) guidance into the lesion, and subsequent injection of mobile tracer subdermally to localize the sentinel node (SN). Patients then underwent breast surgery and SNB. Results: Breast lesions were localized by ROLL in 99.6% of cases and were removed radically with negative margins in 91.9% of cases. Sentinel nodes were detected in all but one case. Intraoperative or definitive histological examination revealed 776 invasive/microinvasive carcinomas and 182 with in situ disease. Sentinel nodes were positive in 154 (19.8%) of 776 invasive/microinvasive cancers and in two with ductal intraepithelial neoplasia (1.1%). Conclusions: In SNOLL the injection procedures are performed separately, but both lesion and SNs are removed together; axillary dissection is performed if the SN is positive, thus definitive treatment of malignant non-palpable lesions occurs in a single surgical session.