Sentinel lymph node positivity of patients with ductal carcinoma in situ or microinvasive breast cancer

Purpose The purpose of this study was to determine the rates of sentinel lymph node (SLN) positivity in patients with a final diagnosis of ductal carcinoma in situ (DCIS) or microinvasive breast cancer (MIC). Methods One hundred thirty patients underwent SLN mapping from 1998 to 2003 for DCIS or MIC. Results One hundred nine patients with DCIS and 21 with MIC underwent SLN mapping. One patient with bilateral DCIS underwent 2 SLN procedures; therefore, the results of 131 SLN procedures are included. On hematoxylin and eosin (H&E) staining, 4 of 110 patients (3.6%) with DCIS had positive SLNs. Four additional patients had positive SLNs by IHC staining only (3.6%). Two of 8 patients underwent completion axillary dissection, and neither had additional involved nodes on completion axillary dissection. One of the 21 patients with MIC had positive SLNs by hematoxylin and eosin (H&E) (4.8%), and another had an involved SLN by IHC staining (4.8%). The patient with the positive SLN by H&E had 1 additional node on completion axillary dissection. Conclusion Rates of SLN positivity for patients with DCIS are modest, even in a high-risk population, and there is continuing uncertainty about its clinical importance.