Does failed mapping predict sentinel lymph node metastasis in cN0 breast cancer?

Lay abstract To study the clinical significance of nonvisualized sentinel lymph nodes (non-vSLNs) in axillary surgery for breast cancer, 30,508 consecutive SLN procedures performed at a single institution from 2000 to 2017 were retrospectively reviewed with the aim to analyze the incidence of non-vSLNs on lymphoscintigraphy, the identification rate during surgery, factors associated with non-vSLNs and related axillary management. Associations between clinicopathological factors and the identification of SLNs during surgery were assessed. Non-vSLN occurred in 525 of the procedures (1.7%). In 73.3%, at least one SLN was identified intraoperatively. Nodal involvement was only significantly associated with SLN nonidentification (p < 0.001). Patients with non-vSLN had an increased risk for SLN metastasis. The detection rate during surgery was consistent, reducing the amount of unnecessary axillary dissection.