Objective: The aim of this study is to assess the role of sentinel lymph node (SLN) biopsy in patients with pure ductal carcinoma in situ of the breast (DCIS) as a rationale for recommending the best managing option for the treatment of such patients in daily practice.
Summary background data: DCIS cannot give rise to axillary metastases by definition. Axillary dissection is therefore not indicated. The role of SLN biopsy in the management of DCIS has not yet been established.
Methods: From March 1996 to September 2006, 854 patients with pure DCIS underwent SLN biopsy at the European Institute of Oncology. Clinical and pathologic data were prospectively collected. When previous surgery or stereotactic biopsy had been performed elsewhere, all the histopathological preparations were reviewed. Patients with microinvasion were excluded from this investigation. Lymphatic mapping was performed using a radiocolloid technique.
Results: SLN metastases were detected in 12 (1.4%) DCIS patients. In 7 cases, only micrometastases (<2 mm) were diagnosed and in 5 cases macrometastases. In addition, isolated tumoral cells (ITC) (<0.2 mm) were identified in 4 additional patients. Eleven patients underwent complete axillary dissection. None of these patients had additional positive axillary lymph nodes.
Conclusions: Because of the low prevalence of metastatic involvement, SLN biopsy should not be considered a standard procedure in the treatment of all patients with DCIS. The sole criteria for proposing SLN biopsy in DCIS should be when there exists any uncertainty regarding the presence of invasive foci at definitive histology.