Ductal carcinoma in situ: value of sentinel lymph node biopsy

BACKGROUND: Ductal carcinoma in situ (DCIS) represents about 20% of newly diagnosed breast carcinomas. Axillary metastasis is often related to undiagnosed DCIS with microinvasion (DCISM). The aim of this study was to confirm the interest of sentinel lymph node (SLN) biopsy in extensive DCIS. METHODS: Patients with a diagnosis of DCIS or DCISM and axillary lymph node evaluation were selected. Surgical treatment included SLN biopsy and/or axillary lymph node dissection (ALND). Serial sections were stained with hematoxylin and eosin (H&E) and with an immunohistochemical (IHC) method. When a micrometastasis was found, the breast specimen was revised searching for occult microinvasion. RESULTS: Hundred and forty patients with initial DCIS were enrolled in the study. Node metastasis was identified in 9 patients (7%) of the 128 patients with DCIS and DCISM. At final histology, 4 (10%) of the 39 patients with pure DCIS and SLN biopsy and 1 (7%) of the 14 patients with DCISM and SLN biopsy had axillary micrometastasis. Four of the 12 patients upstaged to invasive carcinoma had metastatic SLNs. CONCLUSIONS: Sentinel lymph node biopsy is valuable in patients with diffuse DCIS or DCISM who are scheduled for mastectomy in order to search for axillary micrometastases and occult breast microinvasion.