Sentinel lymph node identification in endometrial cancer

Objective To evaluate the feasibility of intra-operative detection of sentinel lymph nodes (SLN) in the patient with endometrial cancer (EC). Methods Thirty-one patients with Stage I and II endometrial cancer, who underwent a hysterectomy and a lymphadenectomy, were enrolled in the study. At laparotomy, methylene blue dye tracer was injected into the subserosal myometrium of corpus uteri at multiple sites, and dye uptake into the lymphatic channels was observed. The blue nodes which were identified as SLNs were traced and excised. The other nodes were then removed. All of the excised nodes were submitted for pathological hematoxylin and eosin (H&E) staining examination. Results Failure of dye uptake occurred in 4 of the 31 cases (12.9%) because of spillage, and no lymphatic coloration was observed there. Lymphatic staining was clearly observable as blue dye diff used to the lymphatic channels of the uterine surface and the infundibulopelvic ligaments in 27 (87.1%) cases. Concurrent coloration in the pelvic lymphatic vessels was also observed in 22 of the 27 patients. The SLNs were identified in 23 of the 27 (85.2%) cases with a lymphatic staining, with a total number of 90 SLNs, and a mean of 3.9 in each case (range, 1–10). Besides one SLN (1.1%) in the para-aortic area, the other 89 (98.9%) were in the nodes of the pelvis. The most dense locations of SLNs included obturator in 38 (42.2%) and interiliac in 19 (21.1%) cases. In our group, pelvic lymphadenectomy was conducted in 27 (87.1%) patients and pelvic nodal sampling in 4 (12.9%). Of the 31 cases, a concurrent abdominal para-aortic lymph node sampling was conducted in 7. A total of 926 nodes were harvested, with an average of 39.8 in each case (range, 14–55). Nodal metastases occurred in 3 patients (9.7%), 2 of them with SLN involvement and the other without SLN involvement. Adverse reactions or injury related to the study was not found. Conclusion Application of methylene blue dye is feasible in an intra-operative SLN identification of endometrial cancer. The technology is convenient, safe, and worth further investigation.