The sentinel node concept in endometrial cancer: histopathologic validation by serial section and immunohistochemistry

Background: The sentinel node (SN) is defined as the first node in the lymphatic system that drains a tumor site. If the SN is not metastatic, then all other nodes should also be disease-free. We used serial sections and immunohistochemical (IHC) staining to examine both SN and non-sentinel nodes (non-SNS). Patients and methods: Twenty-three patients (median age 69 years) with early endometrial cancer underwent a laparoscopic SN procedure based on a combined detection method, followed by complete laparoscopic pelvic lymphadenectomy. If the SN was free of metastasis by both hematoxylin and eosin (H&E) and IHC staining, all non-SNs were also examined by the combined staining method. Results: SNs were identified in 19 patients (82.6%). A total of 47 SNs were removed (mean 2.5). Ten SNs (21.3%) from five patients (26.3%) were found to be metastatic at the final histologic assessment. In 14 patients, no metastatic SN involvement was detected by H&E and IHC staining. In these 14 patients, 120 non-SNs were examined by serial sectioning and IHC, and none were found to be metastatic. Conclusion: The SN procedure appears to reliably predict the metastatic status of the regional lymphatic basin in patients with early endometrial cancer.