Response Evaluation Criteria in Solid Tumors
RECIST is the measurement rulebook that turns serial imaging into a response category — complete, partial, stable, or progressive disease — for oncology trials and routine reporting alike. Version 1.1 refined the original: it reduced the number of target lesions tracked, added specific rules for pathological lymph nodes (short-axis measurement), and clarified progression, making assessments more reproducible across readers and sites. It is the anatomic backbone that PERCIST (metabolic) and iRECIST (immunotherapy patterns) build on, and the criterion radiologists most often look up when dictating an oncology follow-up.
Reduced the number of target lesions, added short-axis measurement for pathological lymph nodes, and clarified progression — improving reproducibility across readers and sites. Basis for iRECIST (immunotherapy).
Introduced unidimensional measurement and the CR/PR/SD/PD categories, replacing the older WHO bidimensional response criteria.
The Radiology Assistant reviews the RECIST 1.1 criteria for tumor response assessment, covering target lesion selection, measurement, and response categories, with a look at newer immunotherapy-specific criteria like iRECIST.
RadPigeon is an independent radiology news digest and is not affiliated with or endorsed by RECIST Working Group. “RECIST 1.1” is a trademark of its owner and is named here only to refer to the system. Always consult the official source for the exact, current criteria.
