Comparing indocyanine green, technetium, and blue dye for sentinel lymph node mapping in endometrial cancer

• Cervical injection of dye allows pelvic & paraaortic mapping of sentinel lymph nodes
• ICG and technetium produce better mapping than blue dye
• Sentinel nodes sometimes map to areas not routinely sampled during lymphadenectomy

Background and aimsWith the debate over extent of lymphadenectomy in endometrial cancer, sentinel lymph node (SLN) mapping may provide a focused approach to evaluate the most relevant lymph nodes (LN) while minimizing the complications. We evaluated SLN mapping using filtered technetium99, indocyanine green (ICG), and blue dye.MethodsProspective evaluation of 100 patients who underwent SLN mapping by using submucosal and deep stromal cervical injections of technetium99, ICG, and blue dye as part of the staging for endometrial cancer.Results286 SLNs were mapped (2.9 per patient) in 92% of patients. The bilateral detection rate was 76%. ICG had a significantly higher SLN detection rate than blue dye in both overall (87% vs 71%, respectively; p = 0.005) and bilateral (65% vs 43%, respectively; p = 0.002) detection, but similar SLN detection rates compared to technetium99 in both overall (87% vs 88%, respectively; p = 0.83) and bilateral (65% vs 71%, respectively; p = 0.36) detection. In eight cases, the SLN was in the para-aortic area and in 14 cases in the pre-sacral, hypogastric vein, or parametrial area. In nine cases, the SLN was positive for metastasis, and in seven cases the SLN was the only positive node. One SLN was falsely negative. No complications or anaphylactic reactions occurred.ConclusionIntra-operative SLN mapping using cervical injection is feasible in patients with endometrial cancer and yields adequate detection rates. It allows mapping of SLNs in areas (pre-sacral, hypogastric vein, parametrial) not routinely sampled. Given the poorer performance of blue dye, surgeons may omit its use if a combination of ICG and technetium99 is used.

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