Chapters Transcript Video Tumor Size Is Associated With Growth Kinetics In Small Renal Masses On Active Surveillance Detailed by Maximilian Pallauf, MD, at the AUA Annual Meeting 2023. Active surveillance is an accepted treatment strategy for small rum masses with a tumor diameter of less than four centimeter. It relies on closed patient and tumor monitoring including regular repeat imaging, a growth rate exceeding half a centimeter a year triggers, delayed intervention. Currently, we lack predictors of growth rate that help us in patient counseling including granular evidence concerning the interaction between tumor size and growth kinetics. The primary aim of the study was to assist the association between tumor size and a growth rate exceeding half a centimeter a year which we defined as a growth rate event. The secondary aims were to evaluate the association between tumor size and delayed intervention and to define the optimal tumor size cut off that predicts growth rate events and delayed intervention. Here, we create the active surveillance arm of the Multicentric prospective observational court study disarmed and identified 456 patients with a minimum imaging interval of six months. We recorded two massa and growth for it. For each follow up visit. We used recurrent event and time to event cox regression modeling and calculated cumulative events and survival plots to test the association between tumor size and growth rate events and delayed intervention. We tested the predictive value of tumor size at first imaging and during active surveillance. So we can account for the change in tumor size over time. We test the tumor size as a continuous variable and des by a predefined cut-off of two centimeters and a cut-off of 2.9 centimeters which we calculated using maximally selected rank statistics based on the time to tumor progression. Tumor size independently predicted growth rate events and delayed intervention. The effect was most prominent using a tumor size cut off of 2.9 centimeters and was accelerated when accounting for the change in tumor size over time. In summary to maize, its available information when counseling patients before enduring active surveillance, small reum masses under 2.9 centimeters are less likely to exceed the growth rate of more than half a centimeter a year or undergo delayed intervention. Created by