Mizuki Nishino, Jyothi P. Jagannathan, Nikhil H. Ramaiya, and Annick D. Van den Abbeele
AJR 2010;195:281-289
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The original RECIST guideline, version 1.0, provided definitions for "measurable lesion" and "nonmeasurable lesion". Measurable lesions must have a longest diameter of ≥ 10 mm on CT with a slice thickness of ≤ 5 mm (or a longest diameter of ≥ 20 mm on nonhelical CT with a slice thickness of > 10 mm) or a longest diameter of ≥ 20 mm on chest radiography
RECIST assigns four categories of response: complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). Assessment of overall response is based on the evaluations of target and nontarget lesions at each follow-up time point. The measurements and response assessment are often recorded using tumor measurement tables.
Major changes in RECIST 1.1 related to imaging include the following: first, the number of target lesions; second, assessment of pathologic lymph nodes; third, clarification of disease progression; fourth, clarification of unequivocal progression of nontarget lesions; and, fifth, inclusion of 18F-FDG PET in the detection of new lesions. The number of target lesions to be assessed was reduced from five per organ to two per organ and from a maximum of 10 target lesions total to a maximum of five total.
In RECIST 1.0, there was no clear guideline for lymph node measurement. In RECIST 1.1, detailed instructions about how to measure and assess lymph nodes are provided. Lymph nodes with a short axis of ≥ 15 mm are considered measurable and assessable as target lesions, and the short-axis measurement should be included in the sum of target lesion measurements in the calculation of tumor response as opposed to the longest axis used for measurements of other target lesions
CONCLUSION:
Familiarity with the revised RECIST is essential in day-to-day oncologic imaging practice to provide up-to-date service to oncologists and their patients. Some of the changes in the revised RECIST affect how radiologists select, measure, and report target lesions
