Diagnostic accuracy of sentinel node in endometrial cancer by using hysteroscopic injection of radiolabeled tracer

Objective: Retrospective and perspective series have shown the feasibility of sentinel lymph-node (SLN) identification of pelvic nodes in endometrial cancer using a cervical injection of tracers. We designed a perspective study to assess the detection rate and diagnostic accuracy of the SLN procedure by means of hysteroscopic injection of a radiolabeled tracer in endometrial cancer patients. Methods: Patients with endometrial cancer underwent hysteroscopic technetium injection. SLN assessment was performed intraoperatively. A systematic pelvic and paraaortic dissection was carried out thereafter. SLNs were examined by standard and immunochemistry methods. The primary endpoint was estimation of sensitivity and negative predictive value (NPV) of sentinel-node biopsy. Results: From 2005 to 2010, 80 consecutive patients entered the study. No severe complications occurred during or after the injection or during surgical SLN biopsy. At least one SLN was detected in 76 of the 80 eligible patients. Fifty nine patients were evaluable according to the study protocol. Ten of these patients (17%) had node metastases. Thirty-three patients (56%) had SLN in the para-aortic area. NPV was 98% (95% CI 89.4-100) and sensitivity 90% (55.5-99.8). Conclusions: SLN detection for endometrial cancer patients has a high sensitivity and NPV when injection is carried out by hysteroscopy. The occurrence of a 56% of sentinel node in paraaortic area may suggest a better sensitivity in this area using hysteroscopic injection compared to cervical injection.