RESPONSE EVALUATION CRITERIA IN SOLID TUMORS VERSION 1.1

Objective assessment of tumor response to treatment is an integral and increasingly important role of radiologists and is essential in day to day oncologic imaging. RECIST published in 2000 by an international collaboration and revised as RECIST
1.1 in 2009. The RECIST criteria have been adopted by academic institutions, regulatory authorities, and the pharmaceutical industry, in which the primary end points are objective response or progression. In this talk, RECIST criteria, including its terms, rules and methods will be discussed.
There are also special problems in evaluation of some tumors’ response to treatment such as tumor necrosis or cavitation which will be clarified.
Concerns about using RECIST and its shortcomings will also be explained.Because many newer cancer therapies may be more cytostatic than cytocidal, good tumor response may be associated predominantly with a decrease in metabolism, without a major reduction in tumor size. This has led to development of tumor- or therapy- specific guidelines such as modified RECIST, which will be reviewed.
Finally, future trends and modifications of RECIST
will be presented.