Objective: To describe the accuracy of SLN mapping in patients with a preoperative diagnosis of grade 1 endometrial cancer.
Methods: A prospective, non-randomized study of women with a preoperative diagnosis of endometrial cancer and clinical stage I disease was conducted. A subset analysis of patients with a preoperative diagnosis of grade 1 endometrial endometrioid cancer was performed. All patients had preoperative lymphoscintigraphy with Tc99m on the day of or day before surgery followed by an intraoperative injection of 2 cm(3) of isosulfan or methylene blue dye deep into the cervix or both cervix and fundus. All patients underwent hysterectomy, bilateral salpingo-oophorectomy, and regional nodal dissection. Hot and/or blue nodes were labeled as SLNs and sent for histopathological analysis.
Results: Forty-two patients with a preoperative diagnosis of grade 1 endometrial carcinoma treated from 3/06 to 8/08 were identified. Twenty-five (60%) had laparoscopic surgery; 17 (40%) were treated by laparotomy. Preoperative lymphoscintigraphy visualized SLNs in 30 patients (71%); intraoperative localization of the SLN was possible in 36 patients (86%). A median of 3 SLNs (range, 1-14) and 14.5 non-SLNs (range, 4-55) were examined. In all, 4/36 (11%) had positive SLNs-3 seen on H&E and 1 as cytokeratin-positive cells on IHC. All node-positive cases were picked up by the SLN; there were no false-negative cases. The sensitivity of the SLN procedure in the 36 patients who had an SLN identified was 100%.
Conclusion: Sentinel lymph node mapping using a cervical injection with combined Tc and blue dye is feasible and accurate in patients with grade 1 endometrial cancer and may be a reasonable option for this select group of patients. Regional lymphadenectomy remains the gold standard in many practices, particularly for the approximately 15% of cases with failed SLN mapping.