Background: In Hodgkin disease (HD), accurate assessment of the extent of disease is essential because it provides the basis for different treatment strategies. In addition to conventional imaging methods (CIM), positron emission tomography with fluorine-18-fluorodeoxyglucose (FDG-PET) may permit reliable differentiation between lymphoma and nonmalignant tissue and thus improve determination of the stage of the disease. The aim of the current study was to assess the clinical value of FDG-PET for primary staging, treatment monitoring, and assessment in a suspected case of recurrent HD.
Methods: Eighty-one patients with HD underwent 106 FDG-PET studies using a dedicated whole body PET ring scanner. In 25 patients PET was part of the primary staging, 63 PET studies were undertaken for treatment monitoring after the completion of treatment, and in 18 patients PET was performed in cases of suspected recurrence of HD. PET scans were compared with CIM and verified histologically and/or by follow-up evaluation (mean follow-up duration, 20.4 months).
Results: With regard to primary staging, in a patient to patient analysis, both PET scans and CIM were positive (i.e., showed pathologic foci indicative of HD) in 24 of 25 cases. In a staging-relevant lesion to lesion analysis, accuracy in the determination of the stage of disease was 96% for PET versus 56% for CIM. PET led to a lower stage classification in 28% and a higher stage classification in 12% of cases, compared with the stage assumed with CIM. With regard to treatment monitoring, PET showed an accuracy of 91% compared with 62% for CIM. The negative predictive value of PET was 96%. With regard to suspected recurrence, PET findings were true-positive in 10 of 12 PET scans and true-negative in 5 of 6 PET scans, resulting in accuracy of 83%, which compares favorably with the accuracy rate of 56% for CIM.
Conclusions: It may be concluded that FDG-PET is capable of determining the stage of HD with great accuracy and is capable of correctly detecting manifestations of HD in treatment monitoring and cases of suspected recurrence, in which CIM occasionally result in equivocal findings. The results of the current study suggest that FDG-PET should become a routine tool in the staging/restaging of HD.