Table 5 Revised Cheson Criteria for Malignant Lymphoma

CR

Disappearance of all evidence of disease

• FDG-avid or PET positive prior to therapy; mass of any size permitted if PET negative

• Variably FDG-avid or PET negative; regression to normal size on CT

Not palpable, nodules disappeared

Infiltrate cleared on repeat biopsy; if indeterminate by morphology, immunohistochemistry should be negative

PR

Regression of measurable disease and no new sites

≥ 50 % decrease in SPD of up to 6 largest dominant masses; no increase in size of other nodes;

• FDG-avid or PET positive prior to therapy; one or more PET positive at previously involved site

• Variably FDG-avid or PET negative; regression on CT

≥ 50 % decrease in SPD of nodules (for single nodule in greatest transverse diameter); no increase in size of liver or spleen

Irrelevant if positive prior to therapy; cell type should be specified

PD or relapsed disease

Any new lesion or increase by ≥ 50 % of previously involved sites from nadir

Appearance of a new lesion(s) > 1.5 cm in any axis, ≥ 50 % increase in SPD of more than one node, or ≥ 50 % increase in longest diameter of a previously identified node > 1 cm in short axis; lesions PET positive if FDG-avid lymphoma or PET positive before therapy

> 50 % increase from nadir in the SPD of any previous lesions

New or recurrent involvement

SD

Not meet above criteria

• FDG-avid or PET positive prior to therapy; PET positive at prior sites of disease and no new sites on CT or PET

• Variably FDG-avid or PET negative; no change in size of previous lesions on CT