An argument against routine sentinel node mapping for DCIS

Indications for sentinel lymph node mapping (SLNM) for patients with ductal carcinoma in situ (DCIS) of the breast are controversial. We reviewed our institutional experience with SLNM for DCIS to determine the node positive rate and clarify indications for nodal staging in patients with DCIS. Since 1998 we have used SLNM to stage breast cancer patients using both blue dye and radiocolloid. In DCIS patients, SLNM has been reserved for patients considered at high risk for harboring coexistent invasive carcinoma or treated by mastectomy. All sentinel nodes were evaluated with serial sectioning, hematoxylin and eosin staining, and immunohistochemical evaluation for cytokeratins. We identified 44 patients with 46 cases of DCIS (two patients with bilateral disease). SLNM identified at least one sentinel node in all cases. In all cases, the sentinel node(s) were negative for axillary metastasis. We calculated the binomial probability of observing 0 of 46 cases as negative when the expected incidence according to published reports in the surgical literature was 13 per cent and found a P value of <0.01. Based on this case-series observation, we conclude SLNM should not be routinely performed for patients with DCIS. We now use SLNM only for DCIS patients treated by mastectomy.