Sentinel Lymph Node Biopsy in Endometrial Cancer: Dual Injection, Dual Tracer—A Multidisciplinary Exhaustive Approach to Nodal Staging

SIMPLE SUMMARY: Since clinical guidelines accepted the utilization of sentinel lymph node (SLN) in apparent uterine-confined endometrial cancer (EC), many centers have already used it as a standard staging surgery. The most widely accepted tracer is ICG alone, but several studies comment on the importance of surgeon experience in order not to lose sensitivity in the first 30-40 cases. This is a prospective, observational single-center trial designed to improve SLN detection rate specially during learning curve. The application of dual tracer (indocyanine green (ICG) and Technetium99 (Tc99) injected separately) helps us to reach a very good overall and bilateral SLN pelvic detection rate in early-stage endometrial cancer patients. Dual injection (cervical and fundal) improves para-aortic SLN detection rate. ABSTRACT: Introduction: Sentinel lymph node (SLN) has recently been introduced as a standard staging technique in endometrial cancer (EC). There are some issues regarding team experience and para-aortic detection. Objective: to report the accuracy of SLN detection in EC with a dual tracer (ICG and Tc99) and dual injection site (cervix and fundus) during the learning curve. Methods: A prospective, observational single-center trial including 48 patients diagnosed with early-stage EC. Dual intracervical tracer (Tc99 and ICG) was injected at different times. High-risk patients had a second fundus injection with both tracers. Results: the detection rates were as follows: 100% (48/48) overall for SLNs; 98% (47/48) overall for pelvic SLNs; 89.5% (43/48) for bilateral SLNs; and 2% (1/48) for isolated para-aortic SLNs. In high-risk patients, the para-aortic overall DR was 66.7% (22/33); 60.7% (17/28) with ICG and 51.5% (17/33) with Tc99 (p = 0.048)). Overall rate of lymph node involvement was 14.6% (7/48). Macroscopic pelvic metastasis was found in four patients (8.3%) and microscopic in one case (2%). No metastasis was found in any para-aortic SLNs. Half of the patients with positive pelvic SLNs had positive para-aortic nodes. In high-risk patients, when para-aortic SLNs mapped failed, 36.4% (4/11) had positive nodes in para-aortic lymphadenectomy. The sensitivity and negative predictive value (NPV) of SLN pelvic detection was 100%. Conclusions: Multidisciplinary exhaustive approach gives a suitable accuracy of SLN during learning curve. Dual injection (cervical and fundal) with dual tracer (ICG and Tc99) offers good overall detection rates and increases para-aortic SLN detection.