Trend and characteristics of minimally invasive surgery for patients with endometrial cancer in Japan

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.

Cost-effectiveness analysis of hospital treatment volume and survival outcomes in endometrial cancer in Japan

OBJECTIVE

Hospital treatment volume affects survival in patients with endometrial cancer; notably, initial treatment at high-volume centers improves survival outcomes. Our study assessed the effect of hospital treatment volume on cost-effectiveness and survival outcomes in patients with endometrial cancer in Japan.

METHODS

A decision-analytic model was evaluated using the following variables and their impact on cost-effectiveness: 1) hospital treatment volume (low-, intermediate-, and high-volume centers) and 2) postoperative recurrent risk factors based on pathological findings (high- and intermediate-risk or low-risk). Data were obtained from the Japan Society of Obstetrics and Gynecology database, systematic literature searches, and the Japanese Diagnosis Procedure Combination database. Quality-adjusted life years (QALY) was used as a measure of effectiveness. The model was built from a public healthcare perspective and the impact of uncertainty was assessed using sensitivity analyses.

RESULTS

A base-case analysis showed that the incremental cost-effectiveness ratio at high-volume centers was below a willingness-to-pay (WTP) threshold of ¥5,000,000 with a maximum of ¥3,777,830/4.28 QALY for the high- and intermediate-risk group, and ¥2,316,695/4.57 QALY for the low-risk group. Treatment at the high-volume centers showed better efficiency and cost-effectiveness in both strategies compared to intermediate- or low-volume centers. Sensitivity analyses showed that the model outcome was robust to changes in input values. With the WTP threshold, treatment at high-volume centers remained cost-effective in at least 73.6% and 78.2% of iterations for high- and intermediate-risk, and low-risk groups, respectively.

CONCLUSION

Treatment at high-volume centers is the most cost-effective strategy for guiding treatment centralization in patients with endometrial cancer.