What is RECIST?


What are the challenges in using RECIST in cancer trials?


How can Calyx help improve cancer trials?

RECIST (Response Evaluation Criteria In Solid Tumors) is a set of published rules that define when cancer patients improve ("respond"), stay the same ("stable") or worsen ("progression") during treatments.

The original criteria were published in February 2000 by an international collaboration including the European Organization for Research and Treatment of Cancer (EORTC), National Cancer Institute (NCI) of the United States and the National Cancer Institute of Canada Clinical Trials Group.

RECIST 1.1, published in January 2009, is an update to the original criteria. Today, the majority of clinical trials evaluating cancer treatments for objective response in solid tumors are using RECIST.


Cancer trials are increasingly complex, involving dozens or even hundreds of investigators from centers around the world. While the RECIST rules are highly dependent upon measurement of tumor size, different clinicians may vary greatly in their methods of performing these measurements.

Consistency in following the imaging requirements and rules is even more challenging. When investigators vary in how they follow RECIST as a trial endpoint, the study results may be placed in jeopardy by significant levels of variability.


Calyx offers two solutions for improving cancer trial endpoints, the RECIST Kiosk and independent endpoint review.

The RECIST Kiosk is a computer-based training center designed to improve how investigators apply RECIST and RECIST 1.1 in cancer trials.

Independent Endpoint Review
Calyx offers independent endpoint review services, including the central collection of all patient images (CT, MRI, X-Ray, or PET), quality control of study images, development of a central digital warehouse of all images and an independent review by blinded Radiologists and Oncologists.



More about RECIST on the EORTC website.