UK multicentre prospective evaluation of the Leibovich score in localised renal cell carcinoma: performance has altered over time

Abstract Objectives To examine changes in outcome by the Leibovich score using contemporary and historic cohorts of patients presenting with renal cell carcinoma (RCC) Patients and methods Prospective observational multi-centre cohort study, recruiting patients with suspected newly diagnosed RCC. A historical cohort of patients was examined for comparison. Metastasis-free survival (MFS) formed the primary outcome measure. Model discrimination and calibration were evaluated using Cox proportional hazard regression and the Kaplan-Meier method. Overall performance of the Leibovich model was assessed by estimating explained variation. Results 706 patients were recruited between 2011-2014 and RCC confirmed in 608 (86%) patients. Application of the Leibovich score to patients with localised clear cell RCC in this contemporary cohort demonstrated good model discrimination (c-index=0.77) but suboptimal calibration, with improved MFS for intermediate- and high-risk patients (5-year MFS 85% and 50%, respectively) compared to the original Leibovich cohort (74% and 31%) and a historic (1998-2006) UK cohort (76% and 37%). The proportion of variation in outcome explained by the model is low and has declined over time (28% historic versus 22% contemporary UK cohort). Conclusion Prognostic models are widely employed in patients with localised RCC to guide surveillance intensity and clinical trial selection. However, the majority of the variation in outcome remains unexplained by the Leibovich model and, over time, MFS rates amongst intermediate- and high-risk classified patients have altered. These findings are likely to have implications for all such models used in this setting.