Introduction: This study aimed to evaluate the accuracy of sentinel lymph node (SLN) biopsy in endometrial cancer across Spain.
Methods: We conducted a multicenter, retrospective study including patients with stage I-II endometrial cancer (according to International Federation of Gynecology and Obstetrics [FIGO] 2009 criteria, all histologies and grades) who underwent SLN mapping from 2015 to 2022. Indocyanine green (ICG), ICG + technetium-99m (99mTC) and 99mTC with different sites of injections (cervical, uterus, or both) were used. Twenty-nine Spanish centers were enrolled.
Results: Overall, 1221 patients were analyzed. The median number of resected SLNs was 2 (interquartile range 1-3); 526 (43%) patients received ICG, 332 (27.1%) patients received ICG + 99mTC, and 363 (29.7%) patients received 99mTC alone or with blue dye. The cervical injection was used in 1121 (92%) patients, 60 (5%) patients underwent a uterine injection, and 40 (3%) patients received both. The bilateral mapping rates were 324 (61.6%) for the ICG group, 250 (75.3%) for the ICG + 99mTC group, and 173 (47.7%) for the 99mTC group (p < 0.001). The aortic mapping rate was 18 (3.4%) for the ICG group, 38 (11.5 %) for the ICG + 99mTC group, and 25 (6.9%) for the 99mTC group, respectively (p < 0.001). Empty node packets were only diagnosed in 10 (1.6%) patients in the ICG group (p < 0.001). The sensitivity was 77% for the ICG group, 90% for the ICG + 99mTC group, and 97% for the 99mTC-alone group. The false negative rates were 6 (3.2%) for the ICG group, 2 (1.4%) for the CG + 99mTC group, and 1 (0.5%) for the 99mTC-alone group (p < 0.244).
Conclusion: We did not find any differences among tracers in terms of accuracy; otherwise, combining 99mTc and ICG achieved the highest overall and bilateral detection rates.
