Sentinel lymph node biopsy in selected cases of ductal carcinoma in situ.

INTRODUCTION: Axillary lymphadenectomy is nowadays not recommended to treat ductal carcinoma in situ (DCIS), but there is controversy surrounding the indication for sentinel lymph node biopsy (SLNB). MATERIALS AND METHODS: A prospective study of a selected group of patients diagnosed preoperatively with DCIS was performed between 2004 and 2009. Indications for SLNB were histologically determined high-grade tumours, tumour size >2 cm and patients scheduled to undergo a mastectomy. RESULTS: Sixty-five patients were analysed. Surgical technique was mastectomy in 39 patients (60%) and conservative breast surgery in 26 (40%). Definitive histological study of the resected breast tumour revealed 43 cases (66.2%) of DCIS, 15 (23.1%) of ductal invasive carcinoma and seven (10.7%) microinvasive tumours. In confirmed DCIS, only 6.9% of sentinel lymph nodes were positive, in microinvasive carcinoma 28.5% and in invasive carcinoma 40% were positive. Total number of patients with positive sentinel lymph nodes was 11 (16.9%). Of 39 mastectomies, 12 corresponded to microinvasive or invasive carcinoma and six (50%) showed a positive SLNB. CONCLUSIONS: Performing SLNB avoids an unnecessary second surgery to study axillary lymph nodes in invasive carcinoma diagnosed after definitive histological study. In patients undergoing a mastectomy, this study requires an axillary lymphadenectomy that is not useful in up to 50% of cases. We think that in a selected group of patients with DCIS, SLNB improves tumour staging, adapts the treatment and avoids second surgery in this group of patients.