Outcomes for Women With Ductal Carcinoma-in-Situ and a Positive Sentinel Node: A Multi-Institutional Audit

Abstract

A positive sentinel lymph node (SLN) has been reported in 6% to 13% of patients with ductal carcinoma in situ (DCIS). Although it is well established that nodal status for invasive disease is prognostically important, the clinical relevance of a positive SLN in patients with DCIS remains undetermined. SLN biopsy was performed on 470 high-risk patients with DCIS (22% of all patients with DCIS) at 3 institutions. Of these, 43 (9%) had SLN metastases. Pathology findings of positive cases were reviewed, and follow-up was obtained. At 2 of the 3 institutions, data were also collected on DCIS patients who had negative findings on SLN biopsy. For these 414 patients, univariate analyses of tumor characteristics were performed to identify factors associated with node positivity. Extensive disease requiring mastectomy (p = 0.02) and the presence of necrosis (p = 0.04) were associated with an increased risk of nodal positivity. Three (7%) of the 43 SLN-positive patients had macrometastases (pN1), 4 (9%) had micrometastases (pN1mi), and 36 (84%) had single tumor cells or small clusters (pN0(i+)). Of the 25 women that underwent completion axillary dissection, one was found to have a macrometastasis. On pathological review of the primary lesion, 2 (5%) of 43 patints were found to have microinvasion, and 2 (5%) lymphovascular invasion. Nine of 43 (21%) high-risk DCIS patients with a positive SLN and 9/470 (2%) of all high-risk DCIS patients were upstaged to AJCC stage I or II as a result of the SLN biopsy. At a median (range) follow-up of 27 (3-88) months, 1 patient had developed hepatic metastases. This patient had immunohistochemistry detected isolated tumor cells in her SLN (N0(i+)), and upon pathologic review, was found to have high-grade DCIS with microinvasion. SLN biopsy for high-risk DCIS patients is a mean of detecting those who may have unrecognized invasive disease and therefore are at risk for distant disease.