Measurability of Tumors at Baseline
- Tumor lesions: Must be accurately measured in at least one dimension (longest diameter in the plane of measurement is to be recorded) with a minimum size of:
- 10mm by CT scan (irrespective of scanner type) and MRI (no less than double the slice thicknessand a minimum of 10mm)
- 10mm caliper measurement by clinical exam (when superficial)
- 20mm by chest X-ray (if clearly defined and surrounded by aerated lung)
Lesions considered truly non-measurable include: leptomeningeal disease, ascites, pleural or pericardial effusion, inflammatory breast disease, lymphangitic involvement of skin or lung, abdominal masses/abdominal organomegaly identified by physical exam that is not measurable by reproducible imaging techniques.
Assessment of Lymph Nodes
- Normal: short axis < 10 mm
- Measurable (Target): short axis ≥ 15 mm
- Non measurable: short axis 10 to < 15 mm
Target nodes measured in the short axis(perpendicular to longest diameter)
Short axes of target nodes to be added to the sum of longest diameter
Baseline Documentation of Target Lesions
All lesions up to a maximum of five lesions total (and a maximum of two lesions per organ) representative of all involved organs should be identified as target lesions
Evaluation of target lesions
- Complete Response (CR): Disappearance of all target lesions.Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to<10 mm.
- Partial Response (PR): At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
- Progressive Disease (PD): At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that is the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. (Note: the appearance of one or more new lesions is also considered progression).
- Stable Disease (SD): Neither sufﬁcient shrinkage to qualify for PR nor sufﬁcient increase to qualify for PD, taking as reference the smallest sum diameters while on study.
Evaluation of non-target lesions
While some non-target lesions may actually be measurable,they need not be measured and instead should be assessed only qualitatively at the time points speciﬁed in the protocol.
- Complete Response (CR): Disappearance of all non-target lesions and normalisation of tumour marker level. All lymph nodes must be non-pathological in size (<10 mm short axis).
- Non-CR/Non-PD: Persistence of one or more non-target lesion(s) and/or maintenance of tumour marker level above the normal limits.
- Progressive Disease (PD): Unequivocal progression (see comments below) of existing non-target lesions. (Note:the appearance of one or more new lesions is also considered progression).
Response Evaluation Criteria in Solid Tumors