Response assessment of aggressive non-Hodgkin's lymphoma by integrated International Workshop Criteria and fluorine-18-fluorodeoxyglucose positron emission tomography.
OBJECTIVE
To determine whether a response classification based on integration of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) into the International Workshop Criteria (IWC) provides a more accurate response assessment than IWC alone in patients with non-Hodgkin's lymphoma (NHL).


METHODS
Fifty-four patients with aggressive NHL who underwent FDG-PET and computed tomography 1 to 16 weeks after four to eight cycles of chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone were assessed for complete response (CR), unconfirmed CR (CRu), partial response (PR), stable disease (SD), and progressive disease (PD) by the IWC and by integrated IWC and FDG-PET (IWC+PET). Progression-free survival (PFS) was also compared between IWC- and IWC+PET-assigned response designations.


RESULTS
By IWC, 17 patients had a CR, seven had a CRu, 19 had a PR, nine had SD, and two had PD. In comparison, by IWC+PET, 35 patients had a CR, 12 had a PR, six had SD, one had PD, and zero had a CRu. In separate multivariate models, PFS was significantly shorter in patients with PR than in those with a CR using IWC (hazard ratio [HR], 8.9; P = .021) or IWC+PET (HR, 29.7; P = .0003). However, when the two classifications were included in the same multivariate model, only IWC+PET was a statistically significant independent predictor for PFS (P = .008 v P = .72 for IWC). In addition, when patients with a PR by IWC and a CR by IWC+PET were compared with those with a CR by IWC and a CR by IWC+PET, there was no significant difference in PFS (HR, 1.6; P = .72), indicating that IWC+PET identified a subset of IWC-PR patients with a more favorable prognosis.


CONCLUSIONS
Compared with IWC, the IWC+PET-based assessment provides a more accurate response classification in patients with aggressive NHL.
Juweid
Malik E
ME
Department of Radiology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA. malik-juweid@uiowa.edu
Wiseman
Gregory A
GA
Vose
Julie M
JM
Ritchie
Justine M
JM
Menda
Yusuf
Y
Wooldridge
James E
JE
Mottaghy
Felix M
FM
Rohren
Eric M
EM
Blumstein
Norbert M
NM
Stolpen
Alan
A
Link
Brian K
BK
Reske
Sven N
SN
Graham
Michael M
MM
Cheson
Bruce D
BD
D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18