What are RECIST 1.1 progressions made of? Variability in double-read oncology trials

Question How does discordance across RECIST components-especially new lesion detection-influence progression assessment timing and potentially alter survival outcomes in oncology clinical trials? Findings Reader disagreement on progression dates is common, driven mainly by new lesion detection; incorporating multiple RECIST components increases alignment and strengthens PD determination reliability. Clinical relevance Imaging endpoints guide cancer treatment decisions. RECIST 1.1 is the standard, inter-reader variability can undermine PFS accuracy. By evaluating RECIST component reliability, this work aims to improve trial precision, enabling faster, more confident decisions that ultimately benefit patients.