Real-time Lymphatic Channel Visualization Improves Bilateral Sentinel Lymph Node Detection in Endometrial Cancer

Overview

Endometrial cancer is the most common malignancy of the female genital tract. Standard treatment for early-stage disease includes hysterectomy, bilateral salpingo-oophorectomy, and lymph node assessment. Sentinel lymph node (SLN) mapping with indocyanine green (ICG) has become widely used as an alternative to systematic lymphadenectomy due to lower morbidity and high detection rates. This randomized clinical trial was designed to compare conventional cervical ICG injection with a modified technique, in which injection is continued until real-time lymphatic channels are visualized intraoperatively, for bilateral SLN detection in patients with clinical early-stage endometrial cancer undergoing robotic surgery.

Primary treatment of clinical early-stage endometrial cancer consists of total hysterectomy, bilateral salpingo-oophorectomy, and lymph node assessment for staging. Sentinel lymph node (SLN) biopsy using indocyanine green (ICG) has been recommended in international guidelines as an alternative to systematic lymphadenectomy. Conventional cervical ICG injection achieves bilateral SLN detection rates of approximately 73-75%. Re-injection may increase detection but prolongs the procedure. To optimize this approach, the investigators developed a modified technique in which ICG injection is continued until real-time lymphatic channels are visualized intraoperatively using the Firefly fluorescence mode of the robotic system. The trial was designed as a prospective, randomized study comparing the conventional method with the modified technique in patients with clinical early-stage endometrial cancer undergoing robotic surgery. Participants were randomized in a 1:1 ratio to either the conventional cervical ICG injection group or the real-time lymphatic channel-guided ICG injection group. Randomization was performed using a computer-generated random sequence. Initially, a sample size of 24 participants per group was planned, assuming bilateral detection rates of 75% (conventional) and 99% (modified). During the course of the study, the observed rates were 82.5% and 97.5%, respectively. A revised power analysis indicated the need for 40 participants per group, and the protocol was amended accordingly. The study was completed with 40 participants in each group. The primary outcome was the rate of bilateral SLN detection. Secondary outcomes included operative parameters and perioperative complications.