Rate of Symptomatic Lymphocele Formation After Extraperitoneal vs Transperitoneal Robot-Assisted Radical Prostatectomy and Bilateral Pelvic Lymphadenectomy

With the peritoneum acting as a natural surface for lymphatic reabsorption, transperitoneal robot-assisted radical prostatectomy (tRARP) is thought to be associated with a lower incidence of symptomatic lymphoceles (SLs) compared with its extraperitoneal counterpart (eRARP) when bilateral pelvic lymph node dissection (BPLND) is performed. In this study, we aim to determine if there is a difference in SL formation and characteristics between the two approaches.We retrospectively reviewed the records of patients who underwent eRARP or tRARP and BPLND by a single surgeon at a tertiary care academic center from July 1, 2003, to May 31, 2016. Patients with a history of prior pelvic radiotherapy, concomitant inguinal hernia repair, RARP without BPLND, or nonadenocarcinoma of the prostate were excluded. The resulting eRARP and tRARP groups were propensity matched for age, body mass index (BMI), American Association of Anesthesiologists (ASA) score, D'Amico risk classification, and pathological lymph node (LN) count.A total of 3183 RARPs were performed during this time period. After applying exclusion criteria and propensity score matching, 671 patients remained in each group. No statistically significant differences were noted between the groups with regard to age, BMI, ASA, pre-RARP prostate-specific antigen, D'Amico risk classification, biopsy and pathological Gleason sum score, pathological T stage, or margin status. The tRARP group had a higher clinical T stage (p = 0.0015), length of stay (LOS; p = 0.005), pathological N stage (4.92% vs 1.36%, p = 0.0002), and high total LN count (7.22 ± 5.54 vs 5.78 ± 4.18 LNs, p 0.0001). The eRARP group had higher operating room times (197.4 ± 48.96 minutes vs 192.2 ± 44.12 minutes, p = 0.04) and estimated blood loss (218.4 ± 152.0 mL vs 179.9 ± 119.4 mL, p 0.0001). No differences were noted in the frequency of SL formation [eRARP: 19/671 (2.83%) vs tRARP: 10/671 (1.49%), p = 0.09] or any clinical characteristics of the SL. Logistic regression analysis showed no effect of LN count (p = 0.071), pathological N stage (p = 0.111), or both combined (p = 0.085) on SL formation.In this cohort, the rate and clinical characteristics of SL were similar among patients treated with eRARP or tRARP and BPLND. The low event rate of SL in each group and trends favoring higher SL with LN yield and pN1 disease in the tRAPR group may deem the study underpowered to make definitive conclusions.