Objectives: The aim of this study was to determine the risk of metastasis in the remaining non-SLNs when the SLN is positive and to identify the factors that can predict this risk.
Methods: We reviewed all patients who underwent primary surgery for endometrial carcinoma with lymphadenectomy and SLN mapping (November 2010-November 2013) in our center. SLNs were ultra-staged on final pathology.
Results: A total of 268 patients were included. Overall, 43/268 patients (16%) were found to have SLN metastasis: macro-metastasis in 24 patients, micro-metastasis in 7 and ITC in 12. Non-SLN metastases were found in 15 of the 43 patients (34.8%) with positive SLN. Size of the SLN metastasis was the only factor associated with an increased likelihood of non-SLN metastasis (p=0.005). When the size of the SLN metastasis was ≤2mm, the risk of having another positive lymph node was only 5%, conversely, when the size of the SLN metastasis was >2mm, the risk of having another positive lymph node was 60.8% (p<0.0001). Histologic type, grade, depth of myometrial invasion, LVSI, cervical stromal invasion and CA-125 were not predictive.
Conclusion: When the SLN is positive, the risk of metastasis in the remaining non-SLNs was 34.8%. Size of the metastasis within the SLN was the only factor that could predict the risk of non-SLN metastasis; 2mm seems to be the cutoff size below which the risk of non-SLN metastasis is low.
Keywords: Completion lymph node dissection; Endometrial cancer; Non-sentinel lymph node metastasis; Sentinel lymph node metastasis.
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