Assessment of Laparotomy Conversion Among Patients Undergoing Minimally Invasive Surgery for Endometrial Cancer: Robotic-Assisted vs Laparoscopic

INTRODUCTION: Minimally invasive surgery, either with robotic-assisted or laparoscopic, to perform total hysterectomy, adnexectomy, and lymph nodal evaluation, is the current mainstay of surgical modality for patients with endometrial cancer. Conversion from minimally invasive surgery to open surgery (laparotomy conversion) may be necessary to complete surgery. OBJECTIVE: To compare the incidence rates and temporal trends of laparotomy conversion between robotic-assisted surgery and laparoscopic surgery for patients with endometrial cancer undergoing hysterectomy-based surgical treatment. METHODS: This retrospective cohort study queried the Commission-on-Cancer’s National Cancer Database. The study population included 181,638 patients with stage I–III endometrial cancer who underwent primary minimally invasive hysterectomy at the intention-to-treat level from 2012 to 2022. The exposure was minimally invasive surgery type, grouped into robotic-assisted or laparoscopic. The main outcome measure was laparotomy conversion, defined as open surgery at the per-procedure level. Temporal trends were assessed with linear-segmented regression with log-transformation. Propensity score inverse probability of treatment weighting cohort was created to assess the exposure-outcome association. The model included patient age, year, comorbidity, primary payer, hospital cancer program type, U.S. region, nodal evaluation type, histology, tumor differentiation, and tumor size. In exploratory analysis, the association between laparotomy conversion and postoperative mortality (30-day and 90-day) was examined. RESULTS: Majority of patients had robotic-assisted surgery (n=141,264, 77.8%), followed by laparoscopic surgery (n=40,374, 22.2%). From 2017 to 2022, utilization of robotic-assisted surgery increased from 76.1% to 82.7% (P-trend<.001). At the whole cohort-level, laparotomy conversion rate decreased by 50% from 3.8% in 2012 to 1.9% in 2022 (P-trend<.001). In the weighted model, robotic-assisted surgery was associated with 77% lower rate of laparotomy conversion compared to laparoscopic surgery (1.5% vs 6.3%, odds ratio OR 0.23, 95% confidence interval CI 0.22–0.24). For all tumor sizes, robotic-assisted surgery had lower rates of laparotomy conversion compared to laparoscopic surgery (OR ranges 0.17 to 0.31), and the inflection point of tumor size for increasing laparotomy conversion rates occurred at larger tumor size for robotic-assisted versus laparoscopic surgery (Fig. 1). The laparotomy conversion rate in the laparoscopic surgery group decreased by 4.7-percentage points from 9.2% in 2012 to 4.5% in 2022; during the same period, the laparotomy conversion rate in the robotic-assisted surgery group decreased by 0.7-percentage points from 2.1% to 1.4% (both, P-trend<.001). As a result, the between-group gap for laparotomy conversion gradually narrowed from 85% (OR 0.15, 95% CI 0.13–0.18) in 2015 to 70% (OR 0.30, 95% CI 0.24–0.37) in 2022 (Fig. 2). Laparotomy conversion was associated with increased incidence rates of 30-day (4.9 vs 2.0 per 1,000, adjusted-OR 2.60, 95% CI 1.91–3.56) and 90-day (9.2 vs 4.8 per 1,000, adjusted-OR 1.90, 95% CI 1.51–2.38) postoperative mortality. CONCLUSIONS: The results of this cohort study suggested that robotic-assisted surgery is associated with substantially lower rates of conversion to open surgery compared to laparoscopic surgery for patients with endometrial cancer. Whether decreasing trends of laparotomy conversion are due to improving patient selection or surgical technique warrants further evaluation. While the reason for laparotomy conversion was not assessable, given its association with postoperative surgical mortality, laparotomy conversion may be considered as a possible quality indicator in endometrial cancer surgery.Figure 1Figure 2