Comparison of central and local serial CT assessments of metastatic renal cell carcinoma patients in a clinical phase IIB study

Background: Clinical oncological studies attempt to improve precision of data by central radiological assessments. However, it is unclear, to which extent local and central assessments diverge. Purpose: To quantify inter-reader variability and the deviation of local from central radiological assessments of computed tomography (CT) scans. Material and Methods: This was a sub-study of a randomized clinical phase IIb trial in metastatic renal cell carcinoma (RCC), comparing first-line sorafenib with interferon-alpha-2a (IFN-alpha-2a). It analyzed agreements of local with central RECIST CT assessments by Cohen's kappa (kappa), symmetry tests, deviations in waterfall plots, Bland-Altman plots, and parametric survival analyses. Conclusion: These data suggest that central radiologic review may reduce technical measurement variability in clinical trials, which should be scrutinized in future studies compared to a volumetric reference