Vial Announces $67M Series B Led by General Catalyst
Read Vial's feature in the WSJ

RECIST

What is RECIST? Responsive evaluation criteria in solid tumors (RECIST) are a set of standardized criteria that is used to evaluate the efficacy of treatments for solid tumors. The criteria are based on the change in one or more tumors observed on imaging such as X-rays, CT, MRI, and F-FDG PET scans. Skin lesions should be documented by color photography using a size standard for scale.

Target lesions are defined as the first two lesions per organ and five lesions in total, and pathologic lymph nodes with a short axis measurement of  ≥ 15mm.

All other lesions are identified as non-target lesions, including pathologic lymph nodes with a short axis measuring 10-15mm. 

 A baseline sum of the longest diameter (LD) of all the target lesions and short axis of pathologic lymph nodes, and the presence of non-target lesions are used to evaluate the changes. 

What are the components of RECIST?

Evaluation of target lesions in response to treatment:

  • Complete response (CR)- All target lesions disappear for at least one month and the short axis of all pathologic lymph nodes decreases to ≤ 10mm.
  • Complete response unknown (CRU)- Complete response which is accompanied by persistent abnormalities of unknown significance on imaging.
  • Partial response (PR)- There is at least a 30% decrease in baseline sum.
  • Stable disease (NR/SD)- There is no significant increase or decrease in the baseline sum since the start of treatment.
  • Progressive disease (PD)- There is an absolute increase of 5mm and a 20% or greater increase in the baseline sum since the start of treatment.

Evaluation of non-target lesions in response to treatment:

  • Complete response (CR)- All non-target lesions resolve and tumor marker levels normalize.
  • Incomplete response/stable disease (SD)- One or more non-target lesion remains, and/or the level of the tumor marker remains elevated.
  • Progressive disease (PD)- There is an appearance of one or more non-target lesions, and/or there is progression of the existing non-target lesions or a general increase in tumor burden.

Source: Nishino et al. (2010). Revised RECIST Guideline Version 1.1: What Oncologists Want to Know and What Radiologists Need to Know. American Journal of Roentgenology, 195(2), 281–289. https://doi.org/10.2214/ajr.09.4110