Predictors of prolonged laparoscopic radical prostatectomy and the creation of a scoring system for the duration

Abstract

Purpose: To identify the relevant factors, and create and validate a predictive scoring system for the duration of laparoscopic radical prostatectomy (LRP). Patients and Methods: We retrospectively analyzed clinicopathological data from 436 patients who underwent LRP between January 2014 and January 2019, of whom 304 cases were used as a model creation group and 132 were used as a validation group. Uni/multi-variate linear regression analysis was performed to determine the predictors of the duration of the procedure and a novel scoring system was created using these predictors. External validation of the scoring system was performed. The Hosmer–Lemeshow test was used to determine the goodness-of-fit of the model and calibration plots were created for visual assessment. Results: “Prolonged duration” was defined as a duration of the procedure that was longer than the mean (>150 min) duration. Multivariate analysis showed that body mass index (BMI), prostate volume, intravesicular protrusion of the prostate (IPP), the ratio of the cross-sectional areas of the prostate and the Retzius space (P/R), pelvic lymph node dissection, and neurovascular bundle (NVB) preservation were significant predictors of prolonged duration. A scoring system that included these six parameters was created and the area under the curve achieved during receiver operating characteristic analysis using this scoring system was 0.874 (95% confidence interval [CI]: 0.836–0.913). The Hosmer–Lemeshow test showed that the scoring system was well calibrated (X2 =5.339, P=0.376). The external validation showed that the model had high predictive accuracy (AUC=0.835, 95% CI: 0.764–0.906) and goodness-of-fit (X2 =4.401, P=0.493). Conclusion: The following factors were significantly associated with prolonged duration of laparoscopic radical prostatectomy: BMI, prostate volume, IPP, P/R, pelvic lymph node dissection, and NVB preservation. The novel scoring system created can be used to accu-rately predict the duration of the procedure, assess the difficulty of surgery, and improve perioperative efficiency.