Background: Sentinel lymph node biopsy (SLNB) is a minimally invasive, accurate method of evaluating axillary lymph nodes in patients with invasive cancer. The technique has also been applied successfully in patients with ductal carcinoma in situ (DCIS). The purpose of this study was to review our experience performing SLNB in patients with a biopsy diagnosis of DCIS.
Methods: A prospective study of consecutive patients seen at our institution from August 2001 to April 2004 with a biopsy diagnosis of DCIS was undertaken. Demographic data, biopsy method, final pathology, and surgical treatment were recorded. Patients undergoing SLNB were identified, and pathologic results were noted.
Results: Eighty-five patients with a biopsy diagnosis of DCIS were treated. Fifty-five (64.7%) had their diagnosis made by excisional biopsy, and 30 (35.3%) by core biopsy. Forty-four (51.7%) patients underwent SLNB as part of their definitive surgical procedure, and an SLN was successfully identified in 41 (93.2%). Nine (22.0%) patients who underwent successful SLNB had a positive SLN, 2 by hematoxylin and eosin (H&E) staining and 7 by immunohistochemical (IHC) staining for cytokeratin. Both patients with H&E-positive SLN were ultimately found to have invasive disease in their primary lesion. Final pathologic assessment of all primary lesions revealed invasive carcinoma in 7, 6 of whom had their diagnosis made by core biopsy. Overall, 20.0% of patients with a core biopsy diagnosis of DCIS were upstaged to invasive disease. Whether the lesion was palpable, grade and the presence or absence of necrosis were not significantly different in patients ultimately found to have invasive disease versus those who did not.
Discussion: Sentinel lymph node biopsy can be performed accurately in patients with a biopsy diagnosis of DCIS. The rate of axillary disease in patients with pure, completely resected DCIS is low; therefore, SLNB is not indicated in all patients with this biopsy diagnosis. Because of a high rate of invasive disease on the final pathology of patients with DCIS diagnosed by core biopsy, these patients should be offered SLNB.