Patient selection: malignant lymphoma, Hodgkin's or non-Hodgkin's disease
The response to therapy may be classified based on:
(1) PET-CT based response, also known as the metabolic response
(2) CT based response, also referred to as the radiologic response
The PET-CT scan would not be relevant if the lymphoma did not show FDG-avidity.
Criteria for PET-CT based progression - any of the following:
(1) FDG uptake of target foci 4 or 5 on the 5-PS with increase relative to baseline:
(2) new or recurrent FDG-uptake in bone marrow
(3) new lesions including extranodal sites
Criteria for CT based progression - any of the following:
(1) enlargement of target node or nodal mass
(2) new or enlargement of any extranodal sites
(3) new splenomegaly or progression of existing splenomegaly
(4) new or recurrent involvement of the bone marrow
(5) new lesions or regrowth of previously resolved lesions
The diagnosis of progression requires exclusion of alternative explanation for findings and may require biopsy confirmation.
Specific rules for a new lesion or node:
(1) The longest diameter is > 1.5 cm.
(2) The diameter is >= 1.5 times diameter at nadir.
(3) The delta diameter is increased:
(3a) if baseline diameter previously <= 2 cm, then delta >= 0.5 cm.
(3b) if baseline diameter previously > 2 cm, then delta > 1.0 cm.
Specific rules for extranodal site:
(1) Any new site > 1.0 cm in any axis.
(2) A new site <= 1.0 cm in diameter if confirmed to be lymphoma on biopsy.
Specific rules for splenomegaly:
(1) With pre-existing splenomegaly: the splenic length must increase by > 50% of its prior increase beyond baseline (if baseline length increased over normal by X, then 1.5*X).
(2) Without pre-existing splenomegal: the length must increase >= 2 cm over baseline.
