The Lancet Oncology publishes iRECIST

RECIST working group issues modified guideline for immunotherapy
Thursday, March 2, 2017
iRECIST - immunotherapy Response Evaluation Criteria in Solid Tumours

Immunotherapeutics trigger different response patterns in tumours than classic chemotherapy drugs.

iRECIST - immunotherapy Response Evaluation Criteria in Solid Tumours

A recent publication in The Lancet Oncology highlights the development, led by the RECIST Working Group, of iRECIST (immunotherapy Response Evaluation Criteria in Solid Tumours) consensus-based guideline, which addresses the novel characteristics of this new class of anticancer therapeutics, ensuring consistent trial design and data collection.

“There are a growing number of new immune modulators being introduced for cancer therapy, and current trials assessing their efficacy are using a variety of response criteria,” said Dr Lesley Seymour, Director of the Investigational New Drug Program, Canadian Cancer Trials Group and lead author on this paper. “The iRECIST guideline, developed by a multidisciplinary group including academic, commercial and regulatory experts, is based on RECIST 1.1 but incorporates additional criteria allowing for consistent interpretation of tumour progression measurements for immunotherapy treatments.”

Novel immunotherapeutics have been shown, in some patients, to trigger different responses in tumours compared to traditional chemotherapy—they may initially increase in size, followed by shrinkage (pseudoprogression). RECIST 1.1. may not capture this unusual pattern of response, however iRECIST allows for the delayed responses that occur after ‘pseudoprogression’, to be identified and better characterized. The guideline describes a standard approach to solid tumour measurement and definitions for objective change in tumour size, which can be used in immunotherapy clinical trials. In addition, it defines the minimum amount of data to be collected in order to create a data warehouse that can be used to later validate iRECIST.. 

Presentation EORTC-NCI-AACR meeting (December 1, 2016)

Earlier this year Dr. Lesley Seymour, CCTG IND Program Director, presented iRECIST, a guideline for data management and data collection for trials testing immunotherapeutics on behalf of the RECIST Working Group, at the EORTC-NCI-AACR (ENA) Molecular Targets and Cancer Therapeutics Symposium in Munich, Germany.

To see a video of Dr. Seymour’s presentation, and access support material for training please visit the iRECIST guideline page.


The RECIST Working Group comprised of representatives of the European Organization for Research and Treatment of Cancer (EORTC), National Cancer Institute (NCI) of the United States and Canadian Cancer Trials Group (CCTG), as well as several pharmaceutical companies. Its mission is to ensures that RECIST undergoes continued testing, validation and updating. To find out more please visit their website.