RECIST (Response Evaluation Criteria in Solid Tumours)

The Response Evaluation Criteria in Solid Tumours (RECIST) criteria was initially published in 2000 by the RECIST working group as an objective method to quantify tumour response. It was subsequently updated in 2009 to RECIST version 1.1, which is described below.¹
It is commonly used in clinical trials to quantify response to oncologic therapy.
There are different criteria for target lesions and non-target lesions:
Target Lesions are selected lesions that are chosen for surveillance of disease response.
- These must be (1) measurable lesions (eg. not leptomeningeal disease), (2) the largest by diameter, (3) represent all involved organs, and (4) should lend themselves to reproducible measurements.
- A maximum of 5 target lesions are chosen.
Non-Target Lesions are any other lesions that are not chosen as target lesions.

RECIST for Target Lesions

Complete Response (CR):
- All target lesions have disappeared during the course of treatment.
- All lymph nodes must be non-pathological in size (<10 mm short axis).
Partial Response (PR):
- At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters when therapy began.
Progressive Disease (PD):
- At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum since therapy began. There must be an absolute increase of at least 5 mm.
- The appearance of one or more new lesions is also considered progression.
Stable Disease (SD)
- Neither sufficient shrinkage to qualify for a partial response nor sufficient increase to qualify for progressive disease.

Complete Response (CR)
- Disappearance of all non-target lesions and normalization of tumour marker levels.
- All lymph nodes must be non-pathological in size (<10 mm short axis).
Non-CR / Non-PD
- Non-Complete Response or Non-Progressive Disease.
- Persistence of one or more non-target lesions and/or maintenance of tumour marker levels above normal limits.
Progressive Disease (PD)
- Unequivocal progression of existing non-target lesions.
- The appearance of one or more lesions is also considered progression.

Target Lesions
Complete Response	All target lesions have disappeared during treatment. All lymph nodes are non-pathologic in size (<10 mm short axis)
Partial Response	At least a 30% decrease in the sum of diameters of the target lesions, where the baseline is defined as the sum of the diameters when treatment began.
Progressive Disease	At least a 20% increase in the sum of diameters of the target lesions, where the baseline is defined as the smallest sum since therapy began. There must be an absolute increase of at least 5 mm The appearance of one or more new lesions is also considered progression.
Stable Disease	Neither sufficient shrinkage to quality for a partial response nor significant increase to qualify for progressive disease.
Non-target lesions
Complete Response	Disappearance of all non-target lesions and normalization of tumour marker levels. All lymph nodes are non-pathologic in size (<10 mm short axis)
Non-CR / Non-PD	Non-Complete Response or Non-Progressive Disease Persistence of one or more non-target lesions and/or maintenance of tumour marker levels above normal limits.
Progressive Disease	Unequivocal progression of existing non-target lesions. The appearance of one or more lesions is also considered progression.

Eisenhauer, Elizabeth A., et al. “New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1).” European journal of cancer 45.2 (2009): 228-247. ↩

Last updated October 27, 2022