External validation of nomograms including MRI features for the prediction of side-specific extraprostatic extension.

BACKGROUND: Prediction of side-specific extraprostatic extension (EPE) is crucial in selecting patients for nerve-sparing radical prostatectomy (RP). Multiple nomograms, which include magnetic resonance imaging (MRI) information, are available predict side-specific EPE. It is crucial that the accuracy of these nomograms is assessed with external validation to ensure they can be used in clinical practice to support medical decision-making. METHODS: Data of prostate cancer (PCa) patients that underwent robot-assisted RP (RARP) from 2017 to 2021 at four European tertiary referral centers were collected retrospectively. Four previously developed nomograms for the prediction of side-specific EPE were identified and externally validated. Discrimination (area under the curve [AUC]), calibration and net benefit of four nomograms were assessed. To assess the strongest predictor among the MRI features included in all nomograms, we evaluated their association with side-specific EPE using multivariate regression analysis and Akaike Information Criterion (AIC). RESULTS: This study involved 773 patients with a total of 1546 prostate lobes. EPE was found in 338 (22%) lobes. The AUCs of the models predicting EPE ranged from 72.2% (95% CI 69.1-72.3%) (Wibmer) to 75.5% (95% CI 72.5-78.5%) (Nyarangi-Dix). The nomogram with the highest AUC varied across the cohorts. The Soeterik, Nyarangi-Dix, and Martini nomograms demonstrated fair to good calibration for clinically most relevant thresholds between 5 and 30%. In contrast, the Wibmer nomogram showed substantial overestimation of EPE risk for thresholds above 25%. The Nyarangi-Dix nomogram demonstrated a higher net benefit for risk thresholds between 20 and 30% when compared to the other three nomograms. Of all MRI features, the European Society of Urogenital Radiology score and tumor capsule contact length showed the highest AUCs and lowest AIC. CONCLUSION: The Nyarangi-Dix, Martini and Soeterik nomograms resulted in accurate EPE prediction and are therefore suitable to support medical decision-making.

Nerve Sparing during Robot-Assisted Radical Prostatectomy Increases the Risk of Ipsilateral Positive Surgical Margins.

PURPOSE: Available published studies evaluating the association between nerve sparing robot-assisted radical prostatectomy and risk of ipsilateral positive surgical margins were subject to selection bias. In this study we overcome these limitations by using multivariable regression analysis. MATERIALS AND METHODS: Patients undergoing robot-assisted radical prostatectomy for prostate cancer at 4 institutions from 2013 to 2018 were included in the study. A multilevel logistic random intercept model, including covariates on patient level and side specific factors on prostate lobe level, was used to evaluate the association between nerve sparing and risk of ipsilateral positive margins. RESULTS: A total of 5,148 prostate lobes derived from 2,574 patients who underwent robot-assisted radical prostatectomy were analyzed. Multivariable analysis showed nerve sparing was an independent predictor for ipsilateral positive margins (OR 1.42, 95% CI 1.14-1.82). Other significant predictors for positive margins were prostate specific antigen density (OR 3.64, 95% CI 2.36-5.90) and side specific covariates including highest preoperative ISUP (International Society of Urological Pathology) biopsy grade (OR 1.58, 95% CI 1.13-2.53; OR 1.62, 95% CI 1.13-2.69; OR 2.11, 95% CI 1.39-3.59 and OR 4.43, 95% CI 3.17-10.12 for ISUP grade 2, 3, 4 and 5, respectively), presence of extraprostatic extension on magnetic resonance imaging (OR 1.42, 95% CI 1.03-1.91) and percentage of positive cores on systematic biopsy (OR 3.82, 95% CI 2.50-5.86). CONCLUSIONS: Nerve sparing was associated with an increased risk of ipsilateral positive surgical margins. The increased risk of positive margins should be considered when counseling patients who opt for nerve sparing robot-assisted radical prostatectomy.

Case report: retroperitoneoscopic tumor nephrectomy during pregnancy.

When considering laparoscopic tumor nephrectomy during pregnancy, questions will arise about the consequences of the increased abdominal pressure (IAP) for uterine-placental perfusion and the impact of carbondioxide insufflation on the fetus. These considerations should be weighed against the advantages for the mother, in term of shorter convalescence and decreased wound problems. This situation presents the urologists with a dilemma. At 16 weeks of gestation, a 30-year-old woman underwent a retroperitoneoscopic tumor nephrectomy. This case report and the following discussion highlight the key issues involved in laparoscopic surgery during pregnancy. In theory, laparoscopy in pregnancy carries some specific hazards, which may influence fetal outcome. First, the elevation of IAP may lead to alterations in placental perfusion, and second, CO2 insufflation may disturb the acid-base balance. However, in a study covering more than 2 million pregnancies, no difference was found in fetal mortality or malformations after laparoscopic surgery for non-obstetric reasons compared with open surgery. Animal experiments have demonstrated an IAP of 15 mm Hg or less to cause almost no reduction in the uterine-placental blood flow. According to our limited experience and with the support of the literature, pneumo(retro)peritoneum during pregnancy seems to be safe.