Sentinel lymph node biopsy may be unnecessary for ductal carcinoma in situ of the breast that is small and diagnosed by preoperative biopsy

概要

Background: Current guidelines do not recommend that sentinel lymph node biopsy (SLNB) is routinely performed for ductal carcinoma in situ (DCIS); thus, indications for SLNB in patients with DCIS remain controversial. In this study, we investigated whether SLNB can be safely omitted when DCIS has been diagnosed by preoperative biopsy.

Methods: We retrospectively analyzed SLN metastasis rates and upstaging to invasive cancer in surgical specimens, performed receiver operating characteristic (ROC) analysis for DCIS lesion size, and assessed correlations with preoperative clinicopathological factors of 277 patients with DCIS diagnosed by preoperative biopsy at our institution.

Results: Among 277 patients with SLNB, six (2.2%) had SLN metastasis. All six were upstaged to invasive cancer by pathological examination of surgical specimens. In total, 69 patients (24.9%) were upstaged to invasive cancer. The mean size of DCIS lesions on preoperative imaging was significantly larger for the 69 upstaged patients (50.0 mm) than for the non-upstaged patients (34.4 mm; P<0.0001). Of the 277 patients with SLNB, 117 (42.2%) had preoperative DCIS lesions smaller than 31.8 mm, which was identified as the optimal cut-off size by ROC analysis. Of these 117 patients, 96 (82.1%, 95% confidence interval; 73.9%–88.5%) could be safely omitted from SLNB because all of them remained as DCIS and had negative SLNs at surgery.

Conclusions: Size of DCIS lesions on preoperative diagnostic imaging is a predictor of diagnosis of invasive cancer on pathological examination of surgical specimens. SLNB may be unnecessary in DCIS diagnosed by preoperative biopsy in patients with small lesions.