Laparoscopic sentinel lymph node mapping with indocyanine green in endometrial cancer: surgeon's learning curve (cumulative sum analysis)

Abstract

Objectives: To evaluate surgeons' learning curves for laparoscopic sentinel lymph node biopsy in endometrial cancer.

Methods: A prospective observational study was performed at the Oncogynecology Center, Lithuanian University of Health Sciences Hospital, from March 2018 to October 2022. Participating surgeons had no previous experience of laparoscopic sentinel lymph node biopsy with indocyanine green tracer. Cumulative sum analysis was used to create learning curves for the performance of eight surgeons, based on a specific result over a time period. Two different cumulative sum plots were made for each surgeon: successful bilateral sentinel lymph node mapping and removal of sentinel lymph node specimens containing actual lymphatic tissue.

Results: 190 patients were included. The overall rate of sentinel lymph node mapping was 89.5%: successful bilateral mapping was achieved in 134 (70.5%) patients, while in 36 (19%) patients sentinel lymph nodes were mapped unilaterally. The bilateral detection rate significantly improved in later study periods (from 59.3% in the first year to 85.0% in the last year; p=0.03). Analysis of the performance of the surgeons for bilateral sentinel lymph node mapping showed that the cumulative sum plot crossed the H₀ limit line after 13 consecutive successful bilateral sentinel lymph node biopsies, indicating an acceptable level of competence to achieve the bilateral detection rate of at least 75%. This was accomplished by only one surgeon after 30 surgeries. Analysis of the performance of the surgeons for identification and removal of specimens containing histologically confirmed lymphatic tissue showed that the cumulative sum plots crossed the H₀ limit line after six consecutive successful sentinel lymph node removals. This was accomplished by most of the surgeons (5 of 8).

Conclusion: At least 30 procedures of indocyanine green traced laparoscopic sentinel lymph node biopsy were needed to reach an acceptable level of competence for a bilateral sentinel lymph node detection rate of at least 75%.

Trial registration number: ACTRN12619000979156.

Keywords: endometrial neoplasms; laparoscopes; sentinel lymph node.