Objective: To evaluate the accuracy of radiological staging, especially renal venous and perirenal fat invasion, in renal cell carcinoma (RCC). Material & Methods: Data of 4823 renal tumor patients from Renal Tumor Database of Association of Uro-oncology in Turkey were evaluated. Of 4823 patients, 3309 RCC patients had complete radiological and histopathological data were included to this study. The Pearson Chi-squared test (χ2) was used to compare radiological and histopathological stages. Results: The mean (SD) age of 3309 patients was 58 (12.3). Preoperative radiological imaging was performed using computed tomography (CT) (n=2510, 75.8%) or magnetic resonance imaging (MRI) (n=799, 24.2%). There was a substantial concordance between radiological and pathological staging (к=0.52, p<0.001). Sensitivities of radiological staging in stage I, II, III and IV were 90.7%, 67.3%, 27.7% and 64.2%, respectively. The sensitivity in stage III was lower than the other stages. Sub-analysis of stage IIIa cases revealed that, for perirenal fat invasion and renal vein invasion, sensitivity values were 15.4% and 11.3%, respectively. Conclusions: There was a substantial concordance between radiological (CT and/or MRI) and pathological T staging in RCC. However, this is not true for T3 cases. Sensitivity of preoperative radiological imaging in patients with pT3a tumors is insufficient and lower than the other stages. Consequently, preoperative imaging in patients with T3 RCC has to be improved, in order to better inform the patients regarding prognosis of their disease.

Introduction: Following the Covid-19 pandemic, the face-to-face meetings are delayed to a future date , which is still not clear. However, seminars, meetings, and conferences are necessary for updating our knowledge and skills. The web-based seminars (webinars) are the solutions to this issue. This study aimed to show the participant behavior when webinars present at the Covid-19 pandemic era. Methods: Between December 2017 – July 2020, 58 webinars were broadcasted via the Uropedia, electronic library of SUST. Data of all webinars were collected with the YouTube analytics and application of the Uropedia. Data of streaming webinars included participant behaviors such as content views, engagement time, total unique attendees, average engagement time, and the number of audience to leads. Data were split into two groups; group-1 is webinars before Covid-19 (before March 2020), group-2 is the webinars during Covid-19. Results: Total broadcast time and total page view number were found to be 112.6 hours (6761 min.) and 15919, respectively. The median participant age was 40.1 years. Median content view and median engagement time were found to be 261.0 min., and 12.2 min., respectively. Comparison of two groups revealed a significant increment in the content views (group 1;134.0 range=86.0-87.0 and group 2; 414.0 range=296.0-602.0, p<0.001) and the number of the unique attendees (group 1; 18.0 range=10.0-26.0 and group 2; 57.0 range=27.0-100.0, p<0.001) following Covid-19. However, the median engagement time of the audience did not seem to change with the Covid-19 pandemic (group 1; 11.5 range=10.0-13.3 min. and group 2; 13.2 range=9.4-18.1 min., p=0.12). Conclusion: The webinars are effective ways to share information and have many advantages, including low cost, reaching the high number of audiences. Audience number and page visits seemed to increase following the Covid-19 pandemic. However, The engagement time did not seem to affect a critical attitude of the audience