Comparison of Oncological Outcomes between Transperitoneal and Retroperitoneal Approaches in Laparoscopic Nephroureterectomies for Upper Tract Urothelial Carcinoma

Background and Objectives: Our aim was to clarify the oncological outcomes of the two different approaches to laparoscopic nephroureterectomies (LNUs) in Japan, and to examine whether there were any significant differences between the transperitoneal approach and the retroperitoneal approach. Materials and Methods: We retrospectively evaluated patients who underwent an LNU for upper tract urothelial carcinoma (UTUC) from January 2013 to December 2022. We identified 52 patients who underwent a transperitoneal LNU (tLNU) and 93 who underwent a retroperitoneal LNU (rLNU). We adopted age, smoking, and pT-stage matching, and 43 patients were classified in each group. We investigated the time from surgery to recurrence (RFS: recurrence-free survival), the time to death (OS: overall survival), and the time to non-urothelial-tract recurrence-free survival (NUTRFS). A Cox regression analysis was performed to evaluate the risk factors that influenced recurrence. Results: There were no significant differences in the RFS, OS, and NUTRFS between the two matched groups. In the multivariate Cox regression analysis, the pT stage (pT3 >= vs. pT2 <=) had an HR = 2.09 and a p = 0.01, and was an independent prognostic risk factor regarding cancer recurrence. Conclusions: There were no significant differences in the oncological outcomes between the tLNU and rLNU groups. It is suggested that the transperitoneal approach should be selected for LNUs.