A retrospective validation study of sentinel lymph node mapping for high-risk endometrial cancer.

OBJECTIVES: To determine the feasibility and performance of sentinel lymph-node (SLN) mapping among women with high-risk endometrial cancer (EC).

MATERIALS AND METHODS: Ninety-eight patients at high-risk EC were enrolled in this retrospective surgical trial from August 2016 to August 2018. All patients underwent intraoperative SLN biopsy, with ICG injection for laparoscopic staging; this was followed by pelvic and paraaortic lymphadenectomy (LAD). Outcomes included SLN detection rate, false-negative SLN algorithm rate, and the negative predictive value (NPV) of the SLN algorithm. The Chi-square test was used to analyze the relationship between SLN mapping and the risk factors. Then, we performed Kappa consistency check (P < 0.05 with Meaning), to estimate the consistency of SLN and lymph-node metastasis.

RESULTS: Successful biopsy occurred in 94 patients (170 sides) among 98 patients (196 sides). At least 1 SLN was identified in 86.7% (170/196). Overall, the false-negative rate (FNR) was 11.8% (2/17), NPV was 97.3% (72/74), and sensitivity was 88.2% (15/17). 22/98 patients (22.4%) with high-risk EC had at least one metastatic lymph node identified. When the SLN algorithm was retrospectively applied, the FNR was 9.1% (2/22) and sensitivity was 90.9% (20/22). Considering the surgeon's experience, 68 cases of EC (except for 30 patients), the detection rate was 89.7% (122/136), NPV was 98.1% (50/51), and the FNR was 5.6% (1/18). The factor significantly affecting the detection rate of SLNs was lymphovascular space invasion (LVSI) (P = 0.016). SLN metastasis of EC was associated with depth of myometrial invasion (P = 0.034). The analysis result of SLN and the consistency of pelvic lymph-node metastasis status. As detected by Kappa coefficient was 0.939 (P < 0.001), suggests highly consistency.

CONCLUSIONS: Our SLN detection rate for high-risk EC was the same as previously reported. When SLN is not detected, better after 30 patients' experience, is a reasonable alternative to complete LAD in high-risk EC. In addition, SLN shows high co-occurrence with pelvic lymph nodes. Therefore, SLN biopsy can be used to diagnose high-risk EC.