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

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). 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. 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. 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.