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.

Is cribriform pattern in prostate biopsy a risk factor for metastatic disease on 68Ga-PSMA-11 PET/CT?

INTRODUCTION: Cribriform growth pattern (CP) in prostate cancer (PCa) has been associated with different unfavourable oncological outcomes. This study addresses if CP in prostate biopsies is an independent risk factor for metastatic disease on PSMA PET/CT. METHODS: Treatment-naive patients with ISUP GG ≥ 2 staged with 68Ga-PSMA-11 PET/CT diagnosed from 2020 to 2021 were retrospectively enrolled. To test if CP in biopsies was an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT, regression analyses were performed. Secondary analyses were performed in different subgroups. RESULTS: A total of 401 patients were included. CP was reported in 252 (63%) patients. CP in biopsies was not an independent risk factor for metastatic disease on the 68Ga-PSMA PET/CT (p = 0.14). ISUP grade group (GG) 4 (p = 0.006), GG 5 (p = 0.003), higher PSA level groups per 10 ng/ml until > 50 (p-value between 0.02 and > 0.001) and clinical EPE (p > 0.001) were all independent risk factors. In the subgroups with GG 2 (n = 99), GG 3 (n = 110), intermediate-risk group (n = 129) or the high-risk group (n = 272), CP in biopsies was also not an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT. If the EAU guideline recommendation for performing metastatic screening was applied as threshold for PSMA PET/CT imaging, in 9(2%) patients, metastatic disease was missed, and 18% fewer PSMA PET/CT would have been performed. CONCLUSION: This retrospective study found that CP in biopsies was not an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT.

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.