ABSTRACT: OBJECTIVE:The aim of the study was to identify risk factors associated with laparotomy conversion during total laparoscopic hysterectomy for endometrial cancer. METHODS:This is a retrospective study examining endometrial cancer cases that underwent hysterectomy-based surgical staging initiated via conventional laparoscopic approach. Factors related to patient, tumor, and surgeon were examined to establish risk of laparotomy conversion using a multivariate logistic regression model. RESULTS:There were 251 cases identified including 30 cases (12.0%) of laparotomy conversion. The most common indication for laparotomy conversion was a large uterus (27.0%), followed by extensive adhesions (24.3%) and surgical complications (18.9%). Outcomes of cases resulting in laparotomy conversion include longer surgical time (333 vs 224 minutes, P < 0.001), larger blood loss (350 vs 100 mL, P < 0.001), longer hospital stay (4 vs 2 days, P < 0.001), and increased risk of hospital readmission (10% vs 1.4%, P = 0.024). In multivariate analysis, morbid obesity (odds ratio [OR], 4.51; P = 0.011), suboptimal pelvic examination or enlarged uterus during preoperative evaluation (OR, 3.55; P = 0.034), para-aortic lymphadenectomy (OR, 10.5; P = 0.001), uterine size 250 g or greater (OR, 3.49; P = 0.026), and extrauterine disease (OR, 4.68; P = 0.012) remained the independent predictors for laparotomy conversion. The following numbers of risk factors were significantly correlated with laparotomy-conversion rate: none, 1.1%; single risk factor, 5.3% (OR, 5.00; P = 0.15); double risk factors, 21.7% (OR, 24.9; P = 0.002); and triple or more risk factors, 50% (OR, 90.0; P < 0.001). Ultrasonographic 3-dimensional volumes of 496 cm in preoperative uterine size correlate with actual uterine weight of 250 g (Y = 61.5 + 0.38X, P < 0.001). CONCLUSIONS:Laparotomy conversion significantly impacts outcomes of patients with endometrial cancer. In this setting, our predictive model for laparotomy conversion will be useful to guide the surgical management of endometrial cancer.