Prognostic value of interim 18F-FDG PET in patients with diffuse large B-Cell lymphoma: SUV-based assessment at 4 cycles of chemotherapy.
Interim (18)F-FDG PET (after 1-4 cycles of chemotherapy) may be useful for tailoring a risk-adapted therapeutic strategy in lymphoma. The purpose of this study was to investigate whether semiquantification of standardized uptake values (SUVs) may help to improve the prognostic value of (18)F-FDG PET, compared with visual analysis, after 4 cycles of chemotherapy.


METHODS
In a previous report, we showed that a 65.7% reduction in maximal SUV (SUVmax) between baseline (PET0) and 2 cycles of chemotherapy (PET2) better predicted event-free survival in 92 prospective patients with diffuse large B-cell lymphoma, by reducing false-positive interpretation of visual analysis. Eighty patients also underwent (18)F-FDG PET after induction had been completed, at 4 cycles of chemotherapy (PET4). Images were interpreted visually (as negative or positive) and by computing the optimal percentage of SUVmax reduction between PET0 and PET4. Survival curves were estimated using Kaplan-Meier analysis and compared using the log-rank test. Median follow-up was 41 mo.


RESULTS
With visual analysis, the 2-y estimate for event-free survival was 82% in the PET4-negative group, compared with 25% in the PET4-positive group (P < 0.0001, accuracy of predicting event-free survival, 81.3%). An optimal cutoff of 72.9% SUVmax reduction from PET0 to PET4 yielded a 2-y estimate for event-free survival of 79% in patients with reduction of more than 72.9%, versus 32% in those with reduction of 72.9% or less (P < 0.0001; accuracy of predicting event-free survival, 77.5%).


CONCLUSIONS
Although SUV semiquantification helps reduce false-positive interim (18)F-FDG PET interpretations at 2 cycles, its performance is equivalent to visual analysis at 4 cycles, when most of the therapeutic effect has occurred upstream. This approach may be useful for objectively tailoring consolidation strategies.
Itti
Emmanuel
E
Department of Nuclear Medicine, H. Mondor Hospital, Assistance Publique-Hôpitaux de Paris, Paris 12 University, UMR CNRS 7054, Créteil, France. emmanuel.itti@hmn.aphp.fr
Lin
Chieh
C
Dupuis
Jehan
J
Paone
Gaetano
G
Capacchione
Daniela
D
Rahmouni
Alain
A
Haioun
Corinne
C
Meignan
Michel
M
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005602:France / Q000453:epidemiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000401:mortality; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data*; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18