RECIST 1.1-Update and clarification: From the RECIST committee

Abstract

The Response Evaluation Criteria in Solid Tumours (RECIST) were developed and published in 2000, based on the original World Health Organisation guidelines first published in 1981. In 2009, revisions were made (RECIST 1.1) incorporating major changes, including a reduction in the number of lesions to be assessed, a new measurement method to classify lymph nodes as pathologic or normal, the clarification of the requirement to confirm a complete response or partial response and new methodologies for more appropriate measurement of disease progression. The purpose of this paper was to summarise the questions posed and the clarifications provided as an update to the 2009 publication.

Keywords: Clarifications; RECIST; Tumour response.

Fig 1

Note optimal manner for measuring the short axis of coalescing lymph nodes (blue arrow). At baseline, there are two distinct nodes, therefore the short axis is measured for each (red and yellow lines) and at cycle 6 the single short axis of the coalesced node is now measured as a single line (red).

Fig. 2

Patient with colorectal cancer. Liver metastases at baseline (red circle) appear to resolved at cycle 3 with “reappearance” at cycle 5 (red circle). However, notice that the imaging techniques are different and the cycle 3 is of poor image quality to visualize these metastases. Therefore, these lesions have not truly reappeared and the patient should not be considered to have progressive disease at cycle 5. There is true progression at cycle 7.