ERUS 2018: Best Poster of ERUS 2018 - Development and Internal-External Validation of a Multivariable Prediction Model for Pre-Operative Assessment of Positive Lymph Nodes During Robot-Assisted Prostatectomy in Two Dutch High Volume Robotic Centers

Marseille, France (UroToday.com) Dr. Collette received the award for best poster of the ERUS 2018 meeting and presented his study in a podium format. In this study, the authors aimed to develop and validate a prognostic model for the prediction of positive lymph nodes during robotic radical prostatectomy (RARP) in a Dutch cohort.

Overall 3349 patients were included in the analysis, between 2009 and 2017, in two high volume robotic centers in the Netherlands. A total of 914 patients (27%) underwent pelvic lymph node dissection (PLND) during the RARP procedure. Positive lymph nodes were found in 168 patients (18%). Mean PSA was 17.2, 34% of the patients were clinical stage T1, 54% were cT2, and 12% were cT3. Biopsy results demonstrated that 12% had Gleason group grade (GG) 1, 23% were GG 2, 24% were GG 3, 26% were GG 4, and 15% were GG 5.

Multivariable logistic regression models were created for each of the two included centers. Later on, cross-over internal-external validation was performed. The results demonstrated that PSA, clinical stage T2 and T3, ad biopsy GG 3 and 4 were all significant predictors (HR 1.01, P=0.025, HR 2.401, p<0.01, HR 4.539, p<0.01, HR 2.474, p=0.015, HR 2.567, p=0.01, respectively). The separate models showed equal discrimination performance with overlapping confidence intervals and a maximum c-index of 0.61 (Figure 1).

Figure 1
Figure 1 – ROC curve:

Dr. Collette summarized and stated that this is the first Dutch diagnostic, predictive model of positive lymph nodes in prostate cancer. In the future, Dr. Collette and his colleagues plan to add % of positive biopsies as a predictor in the models, develop an online risk calculator and perform a nationwide external validation of their results. They also plan to do a head to head comparison of their model with the Briganti and MSKCC nomograms and hopefully change the threshold for the performance of a PLND in the Netherlands.

Presented by: Collette E.R.P, Rijnstate Hospital, Dept. of Urology, Arnhem, Netherlands

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Twitter:@GoldbergHanan at the EAU Robotic Urology Section (ERUS) Meeting - September 5 - 7, 2018 - Marseille, France