Tumour-positive sentinel node findings in patients with ductal carcinoma in situ

Background: Our aim was to evaluate the prevalence of and risk factors for tumour-positive sentinel node (SN) findings in patients with ductal carcinoma in situ (DCIS). Methods: Altogether 1,470 patients underwent sentinel node biopsy (SNB) between April 2001 and March 2005 in our unit. According to a histopathological review, 11 of them had microinvasive and 74 pure DCIS and were included in the study. Results: Five patients (7%) with pure DCIS had SN metastases. Three of them had isolated tumour cells (ITC) only. Axillary clearance without further metastatic findings was performed in three patients. The median histological size of DCIS was larger, 50 (45-60) mm in patients with metastatic SN findings than the median of 18 (2-110) mm in those with tumour-negative SN, P = 0.0103. All five patients with metastatic SN findings underwent mastectomy. Metastatic SN findings were detected in one (9%) patient with microinvasive DCIS. Conclusions: Metastatic SN findings in patients with pure DCIS may be a sign of missed invasion.