Citations

536 Background: The management of malignant mesothelioma of the tunica vaginalis of the testes (MMTVT) is not clearly defined, though retroperitoneal lymph node dissection has been reported as a diagnostic and potentially therapeutic option. Herein we present our experience with robot assisted retroperitoneal lymph node dissection (RARPLND) in a series of patients with MMTVT. Methods: The Mayo Clinic cancer registry was queried from 1972-present for all patients who had a diagnosis of MMTVT. Six patients were identified, five of whom were treated with RPLND, where four underwent RARPLND. Data was collected on pertinent demographic, preoperative, perioperative, postoperative outcomes and follow-up oncological data. Results: In five patients who underwent RPLND, the median age was 50 years (IQR 34-51), median BMI was 26.9 (IQR 26.4-30.6). Four patients originally presented with right sided symptomatic hydroceles, while one presented with right sided chronic epididymitis. Orchiectomy (one simple, two inguinal radical) was performed in three patients and hydrocelectomy in the other two patients prior to presentation. Preoperative cross-sectional imaging, including PET-CT scan in three patients, was negative for lymphadenopathy or metastasis. RARPLND was performed in 4/5 (80%) cases and concomitant hemiscrotectomy in 4/5 (80%) cases. Full bilateral template was performed in three patients and right modified template was performed in the remaining two. Median lymph node yield was 29 (IQR 22-32) and median blood loss was 275 cc (IQR 200-300). Positive retroperitoneal lymph nodes were found in 3/5 (60%) cases. Final margins of hemiscrotectomy were negative in all four cases. All patients who underwent RARPLND were discharged home on postoperative day one. One patient received four cycles of adjuvant Cisplatin and Pemetrexed. Mean follow-up was 27 months (range 2-47). No patients recurred. Conclusions: MMTVT is a very rare malignancy with high potential for retroperitoneal lymph node dissemination. Regardless of the approach, RPLND may provide both a diagnostic and therapeutic benefit, with the robotic approach affording a potentially expedited recovery.

492 Background: There is scant information about intermediate and long-term comparative outcomes between RARC and ORC, with the exception of a recent, small randomized-trial. We present our experience with RARC and ORC in managing bladder cancer patients who require cystectomy. Methods: A query of all patients who underwent radical cystectomy for a primary bladder tumor between 01/2007 and 6/2017 at our institution yield 469 patients. Data was collected on patient demographics, pre-operative information, operative details, pathology, and follow-up. Most RARCs were performed by a high-volume robotic surgeon who preferentially used the robotic approach at the start of all cases. Statistical analyses were generated using SPSS 22.0. Any open conversions were analyzed in the RARC cohort. Results: In 469 total patients, 197 (42.0%) and 272 (58.0%) underwent RARC and ORC, respectively. There were 163 (82.7%) and 224 (82.4%) males in each group and the mean ages (SD) were 71.5 (8.6) and 70.2 (10.5) years. Mean follow-up (SD) was 75 (37.7) and 61 (35.7) months, respectively. There were 130 (66.0%) and 172 (63.2%) patients who presented with T2 or greater disease (p=0.605). Soft-tissue margin rates were 4.1% for RARC and 6.7% for ORC patients (p=0.232). Neoadjuvant chemotherapy was used in 56.9% of RARC and 45.9% of ORC patients with ≥ cT2 disease (p=0.058). The 5-year overall survival was 60.0% vs 57.0% and the 10-year overall survival was 40.3% vs 44.8% for RARC vs. ORC patients, respectively (p=0.283). The 5-year recurrence-free survival was survival (RFS) was 71.7% vs 65.7% and the 10-year RFS was 70.5% vs 62.3% for the RARC vs. open groups, respectively (p=0.078). Aggressive histological variants, which were associated with greater likelihood for recurrence, were more common in the ORC group (13.7 vs. 22.4% p=0.013). Atypical recurrences (i.e. peritoneal, extrapelvic nodes) occurred in 6 (3.0%) and 14 (5.1%) RARC and ORC patients, respectively (p=0.266). Conclusions: In experienced hands, intermediate and long-term outcomes of RARC appear equivalent to ORC with regards to recurrence free survival, overall survival, and risk of atypical recurrences.