The guideline

Novel immunotherapeutics have been seen to trigger different response patterns in tumours than classic chemotherapy drugs, including the so-called ‘pseudoprogressions’, leading to concerns about assessing changes in tumours using existing tools as an objective evaluation of response to the treatment and disease progression. The iRECIST approach allows responses not typically observed in traditional systemic treatment to be identified and better documented. 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 facilitate the creation of a data warehouse that can be used to later validate iRECIST.


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

ENA iRECIST presentation (pdf).


The iRECIST guidelines in the Lancet Oncology (are available online as of March 1, 2017).

iRECIST (peer-reviewed, accepted, unedited version of the article)
iRECIST (accepted, unedited version of supplementary material)


iRECIST training set of slides – this presentation includes the iRECIST slides as presented during ENA, extended with additional examples and clarifications which may be used to train on iRECIST.

Below are examples of case report forms that can be used to collect information to measure response according to iRECIST

pictopdf_16x16_2017 Initial measurement form