Oncological Outcomes of Retroperitoneal Lymph Node Dissection During Retroperitoneal Laparoscopic Radical Nephroureterectomy for Renal Pelvic or Upper Ureteral Tumors: Matched-Pair Analysis

Objectives: The aim of this study was to investigate the oncological outcomes and recurrence patterns in clinically node-negative patients with renal pelvic and/or upper or middle ureteral tumors after template-based retroperitoneal lymph node dissection (RPLND) in conjunction with retroperitoneal laparoscopic radical nephroureterectomy (LRNU). Materials and Methods: A total of 283 patients who received LRNU with and without RPLND at three Japanese institutions were enrolled. The template for RPLND included the renal hilar and para-aortic lymph nodes (LNs) (left side) and renal hilar, paracaval, retrocaval, and intra-aortocaval LNs (right side). The LNs and kidneys were removed en bloc. The primary endpoint was set as recurrence-free survival. All RPLND cases were matched one-to-one with no-RPLND cases using a propensity score matching approach, and 47 matched pairs were included in analyses. Results: Compared with the control group, significant differences were not observed in the RPLND group in terms of operation time, blood loss, postoperative complication rate, and pathological findings. The estimated 5-year recurrence-free survival was significantly higher in the RPLND group (86.8%) compared with the group without RPLND (64.2%) (p = 0.014). The estimated 5-year cancer-specific survival showed a similar tendency; however, it did not reach a statistically significant difference (87.5% vs 71.3%, respectively; p = 0.168). As for the first recurrence site, the RPLND group showed a lower incidence of distant recurrence, while no significant difference was observed in the rate of regional LN recurrence. Conclusions: This study suggests that template-based RPLND in conjunction with retroperitoneal LRNU efficiently improves recurrence-free survival by reducing distant recurrences.