ith almost 61 000 new cases per year, prostate cancer (PCa) is the most common male cancer in Germany (1, 2). Of the potentially curative treatment options, radical prostatectomy with concomitant pelvic lymph node dissection (PLND) is the most commonly chosen surgical procedure (3-5). On the one hand, PLND remains the most accurate staging procedure for the detection of lymphatic metastasis and, on the other hand, the decision on which consecutive treatment should SummaryBackground: Lymphocele is the most common complication arising after pelvic lymph node dissection (PLND) in the setting of robot-assisted radical prostatectomy (RARP). The only data available until now on the utility of a peritoneal flap to prevent lymphocele were retrospectively acquired.Methods: A randomized, controlled, multi-center trial with blinded assessment of endpoints was carried out on 232 patients with prostate cancer who underwent RARP with PLND. The patients in the intervention group were given a peritoneal flap; in the control group, surgery was performed without this modification. The two joint primary endpoints were the rates of symptomatic lymphocele during the same hospitalization as the operative procedure (iT1) and within 90 days of surgery (iT2). The secondary endpoints were lymphocele volume, the need for treatment of lymphocele, complications requiring an intervention, and the degree of postoperative stress incontinence. German Clinical Trials Register number: DRKS00011115.Results: The data were evaluated in an intention-to-treat analysis, which, in this trial, was identical to an as-treated analysis. 108 patients (46.6%) were allotted to the intervention group. There were no statistically significant intergroup differences with respect to any clinical or histopathological criteria. A median of 16 lymph nodes were removed (interquartile range, 11-21). A symptomatic lymphocele arose in 1.3% (iT1) and 9.1% (iT2) of the patients, without any statistically significant difference between the two trial groups (p = 0.599 and p = 0.820, respectively). Nor did the groups differ significantly with respect to lymphocele volume (p = 0.670 on hospital discharge [T1], p = 0.650 90 days after surgery [T2]) or the type and frequency of need for subsequent surgical intervention (p = 0.535; iT2). 81.5% of all patients (n = 189) had no complications at all in the first three months after surgery. Nor were there any intergroup differences at 90 days with respect to the degree of stress urinary incontinence (p = 0.306) or complications (p = 0.486).Conclusion: A peritoneal flap after RARP was not found to influence the rate of postoperative lymphocele, whether asymptomatic or requiring treatment.

<b><i>Introduction:</i></b> Lymphocele (LC) formation is a common complication which may cause severe symptoms after robot-assisted radical prostatovesiculectomy (RARP) with concomitant pelvic lymph node dissection (PLND). Compared to open radical prostatectomy, the amount of data on potential risk factors for LC formation is still limited. The aim of the present study was to identify risk factors for symptomatic LC formation (sLC) after RARP with PLND. <b><i>Methods:</i></b> We used the data of a prospective multicentre series of 232 RARP patients which were treated between March 2017 and December 2017. The primary endpoint was the presence of sLC within 90 days. Asymptomatic LC (aLC) formation was also recorded. We evaluated clinical, perioperative, and histopathological criteria and compared their distribution in patients with and without post-operative sLC. Uni- and multivariable logistic regression analyses (MVAs) were performed to identify potential predictors for LC formation. Regarding the influence of patients’ BMI, 2 models were calculated: BMI continuously (model 1) and BMI dichotomized with cut-off 30 kg/m² (WHO definition, model 2). <b><i>Results:</i></b> Post-operative sLC was present in 21 patients (9.1%), while aLC was detected in 49 patients (21.1%) 90 days after RARP with PLND. Patients with sLC showed higher median baseline PSA levels (9.8 vs. 8.1 ng/mL), higher prevalence of obesity (BMI &#x3e;30; 42.9 vs. 19.9%), and longer median console time (180 vs. 165 min) compared to patients without sLC. On MVA higher BMI {model 1: OR 1.145 (confidence interval [CI] 1.025–1.278); model 2: OR 2.761 (1.045–7.296)}, longer console time (model 1: OR 1.013 [1.005–1.021]; model 2: OR 1.013 [1.005–1.020]) and an ISUP grade ≥3 (model 1: OR 3.247 [1.182–8.917]; model 2: OR 2.791 [1.050–7.423]) were identified as independent predictors for sLC development. <b><i>Conclusion:</i></b> Patients with aggressive tumours and higher BMI should be informed about a potentially increased risk for sLC formation. In case of a long console time, a close and regular follow-up should be considered to check for LC development.

Introduction Current results concerning the effect of body mass index (BMI) on positive surgical margins (PSMs) after robot-assisted radical prostatectomy (RARP) in patients with localized prostate cancer are inconsistent. Therefore, the aim of this study was to further analyse the association between BMI and PSMs after RARP. Material and methods Between March 2017 and December 2017 a multicentre, prospective, randomised, single-blind series with a blinded outcome assessment of 232 RARP patients was performed. Multivariate logistical regression models were used to analyse the independent effect of obesity, with body-mass-index (BMI) dichotomised at 30 kg/m 2 (model-1) and at 90 th percentile (model-2), on PSMs. Results Median BMI was 27.2 kg/m 2 , PSMs were found in 15.5% (n = 36). In multivariate model-1, obesity did not have a significant effect on PSMs (OR 2.34, p = 0.061). However, if BMI was dichotomized at the 90 th percentile (BMI ≥33.7 kg/m²), patients with a higher BMI showed PSMs four-times more frequently (OR 3.99, p = 0.013). In both models, preoperative prostate-specific antigen (PSA) levels and pathological tumour stage had a significant effect on PSMs. There was no significant correlation between BMI and the extent of PSMs, nor a significant difference between the BMI groups and the localisation of PSMs. There was a higher percentage of posteriolateral PSM localisation in obese patients compared to patients with a BMI of less than 30 kg/m 2 (58.3% and 25.3% of the localisations were posterolateral in obese and non-obese patients, respectively), however this effect was not statistically significant (p = 0.175). Conclusions In addition to a longer operation time and about twice as many complications, patients with a BMI of ≥33.7 kg/m² had a higher PSM rate after RARP. Differences in localization of PSMs in relation to obesity should be evaluated in future research.