Selective approach to radionuclide-guided sentinel lymph node biopsy in high-risk ductal carcinoma in situ of the breast

Abstract

Ductal carcinoma in situ (DCIS) currently represents approximately 15-25% of all breast cancers detected. Although inherently a noninvasive disease, occult invasive disease can be found at definitive histology. The role of sentinel lymph node (SLN) biopsy in DCIS is still unclear. The aim of this study was to evaluate the clinical usefulness of SLN biopsy and the incidence of SLN metastases in selected patients with high-risk DCIS, who are at highest risk for being upstaged to invasive carcinoma. Twenty-three high-risk patients with DCIS proven on core biopsy (mean age, 50 years; median age, 48 years; age range, 37-78 years) were included in the study. SLN scintigraphy was performed 2-4 h before surgery by injecting Tc-99m-labeled nanocolloid intradermally in the periareolar region. The first lymph node to appear on the scan was labeled as SLN and was marked on the skin by using a γ probe. The lymph node was explored in the axilla using a γ probe. The SLN was identified in all patients (100% success rate). Of 23 cases of DCIS on core biopsy, seven patients (30%) were shown to have invasive ductal carcinoma on final histological specimen. Among these seven patients, three had minimal invasive carcinoma (<1 cm) and none of these patients had positive SLN for metastases. Among 23 cases, only one patient with (4%) SLN was positive for metastasis despite histopathological diagnosis of pure DCIS. Although the study population is small, our findings suggest that patients with high-risk DCIS have an increased risk of invasive disease, as approximately one-third of these patients had invasive component at the time of definitive operative procedure. Furthermore, the study also suggests that SLNB appears to be reliable in identifying axillary lymph nodes status of these patients.