Clinical outcomes of sentinel node navigation surgery in patients with preoperative estimated stage IA endometrial cancer and evaluation of validity for continuing sentinel node navigation surgery based on dispersion of recurrence probability

Background To evaluate the feasibility of the use and continuation of sentinel lymph node navigation surgery (SNNS) for patients with preoperative estimated stage IA endometrial cancer Methods This retrospective study selected the electronic medical records of all patients who had received CT scans and MRI imaging prior to surgery from April 1, 2009 to March 31, 2021. Sentinel lymph nodes (SLNs) were detected by administrating 99mTc-phytate and/or indocyanine green into the cervix, and the clinical outcomes of the patients who underwent SNNS or pelvic lymph node dissection (PLND) were evaluated. Furthermore, in case of recurrence, a procedure to determine whether the facility should continue with SNNS or not was developed that compares the maximum likelihood hypothesis and an alternative one based on recurrence rates. Results Among 137 patients, SLN biopsies with ultrastaging were performed on 91 patients. The SLN detection rate was 95.6%. During the 59-month median observation period, no statistically significant differences were shown in overall survival, disease-specific survival and disease-free survival between the SNNS and PLND groups when introducing the propensity score method (with p-values of 0.06, 0.153, and 0.625, respectively). Our procedure demonstrated that, in our department without recurrence up to the 65th attempt, it was possible to continue SNNS if a recurrence occurs at the 66th attempt. Conclusions SNNS for patients with preoperative estimated stage IA does not seem to worsen the prognosis. We confirmed the validity of continuing SNNS by using our procedure even in the absence of evidence like randomized control trials.