Sentinel lymph node mapping using indocyanine green and fluorescence imaging in Endometrial Cancer

Abstract

Background: Surgery plays a fundamental role in the treatment of endometrial and cervical cancer. Since lymph node status is one of the most crucial prognostic factors among these patients, lymphadenectomy remains an important step in surgical management. Over the past few years, instead of systemic lymph node dissection, sentinel lymph node (SLN) biopsy has emerged as one of the most promising methods to achieve tailored surgery among patients with uterine or cervical cancer. Different types of dyes and tracers for SLN mapping were explored through that time. Researchers have reported on their experiences with pelvic lymphatic mapping using radio colloids [Technetium-99 (Tc-99)] and colorimetric imaging with blue dyes isosulfan blue (ISB), patent blue, and methylene blue. Indocyanine green (ICG) is the most clinically valuable agent for near-infrared (NIR) lymphatic mapping and its usage has been reported in SLN mapping in endometrial and cervical malignancies obtaining excellent detection rates. Aim: The aim of this study was to estimate the surgical, accurately identify sentinel lymph nodes using indocyanine green and near-infrared fluorescence imaging in endometrial cancer during both open and laparoscopic surgery. Materials and Methods: We reviewed patients with atypical endometrial hyperplasia, clinical stage I and II endometrial cancer who underwent primary surgery with SLN mapping between January 2021 and March 2023. A retrospective analysis of endometrial cancer patients undergoing ICG, SLN mapping ± pelvic (and/or para-aortic lymphadenectomy was performed. Detection rates were calculated for the entire cohort. Sensitivity and false negative rates were calculated for patients undergoing lymphadenectomy after SLN mapping, and surgical outcome was compared among patients undergoing SLN mapping only versus lymphadenectomy. Results: Forty patients were included in the study; cervical indocyanine green injections and sentinel lymph node biopsy were performed in 17 patients during laparoscopy and other 3 patients during open surgery. The median number of sentinel lymph node removed was 7.7 (range 5–15), and overall and bilateral sentinel lymph node detection rates were 95 % (19/20) respectively. Any sentinel lymph node was not identified in one cases. Overall, 15 % (3/20) of patients had lymph node metastases and, in all these cases, a sentinel lymph node was detected bilaterally. The calculated sensitivity of the sentinel lymph node mapping was 95 %; the false negative rate was 5%. The median operation time was 113.3 min, and the median estimated blood loss was 142.5 ml. Sentinel lymph node were most frequently located in the external iliac region (33.3%), followed by obturator fossa (66.7%). No indocyanine green injection-related complications were registered. Conclusion: Based on our experience, sentinel lymph node mapping technique using NIR fluorescence imaging with indocyanine green appears to be an accurate method with high overall and bilateral detection rates in most of the patient’s endometrial cancer, regardless of demographic characteristics, tumor-related features and surgical approach.