Intrauterine manipulator use during laparoscopic hysterectomy for endometrial cancer: association for pathological factors and oncologic outcomes

Objective To examine the association between intrauterine manipulator use and pathological factors and oncologic outcomes in patients with endometrial cancer who had laparoscopic hysterectomy in Japan. Methods This was a nationwide retrospective cohort study of the tumor registry of the Japan Society of Obstetrics and Gynecology. Study population was 3846 patients who had laparoscopic hysterectomy for endometrial cancer from January 2015 to December 2017. An automated 1-to-1 propensity score matching with preoperative and intraoperative demographics was performed to assess postoperative pathological factors associated with the intrauterine manipulator. Survival outcomes were assessed by accounting for possible pathological mediators related to intrauterine manipulator use. Results Most patients had preoperative stage I disease (96.5%) and grade 1–2 endometrioid tumors (81.9%). During the study period, 1607 (41.8%) patients had intrauterine manipulator use and 2239 (58.2%) patients did not. In the matched cohort, the incidences of lymphovascular space invasion in the hysterectomy specimen were 17.8% in the intrauterine manipulator group and 13.3% in the non-manipulator group. Intrauterine manipulator use was associated with a 35% increased odds of lymphovascular space invasion (adjusted odds ratio 1.35, 95% confidence interval (CI) 1.08 to 1.69). The incidences of malignant cells identified in the pelvic peritoneal cytologic sample at hysterectomy were 10.8% for the intrauterine manipulator group and 6.4% for the non-manipulator group. Intrauterine manipulator use was associated with a 77% increased odds of malignant peritoneal cytology (adjusted odds ratio 1.77, 95% Cl 1.29 to 2.31). The 5 year overall survival rates were 94.2% for the intrauterine manipulator group and 96.6% for the non-manipulator group (hazard ratio (HR) 1.64, 95% Cl 1.12 to 2.39). Possible pathological mediators accounted HR was 1.36 (95%Cl 0.93 to 2.00). Conclusion This nationwide analysis of predominantly early stage, low-grade endometrial cancer in Japan suggested that intrauterine manipulator use during laparoscopic hysterectomy for endometrial cancer may be associated with an increased risk of lymphovascular space invasion and malignant peritoneal cytology. Possible mediator effects of intrauterine manipulator use on survival warrant further investigation, especially with a prospective setting.