Purpose: The aim of this study was to determine the ability of 2-deoxy-2-[(18)F]fluoro-d-glucose positron emission tomography (FDG-PET) to predict the clinical outcome of previously treated patients with Hodgkin's Disease (HD).
Patients and methods: Thirty-two patients were studied with PET within a median interval of 5.2 months after treatment. Conventional imaging (CI) performed within two months before PET included 2.9+/-1.2 imaging tests/patient. To determine the independent ability of FDG-PET to predict the clinical outcome, PET images were reread without knowledge of CI and clinical history. Study end points were disease-free survival, or clinical evidence of disease or death. PET and CI stages were also compared for each patient.
Results: Using the clinical outcome as gold standard after a median follow-up of 14 months, 21 of 32 patients (65%) were considered disease-free while 11 of 32 patients (35%) had evidence for disease or had died. The predictive accuracy of PET was 91% vs. 66% for conventional imaging (P<0.05). The positive predictive value (PPV) was also significantly higher for PET (79% vs. 50%, P<0.05), while its negative predictive value (NPV) tended to be higher than that of CI (100% vs. 86%, P=0.08). Kaplan-Meier analysis for disease-free survival showed a significant difference between PET-negative and -positive results. No such difference was observed between CI-positive and -negative results (P=0.35).
Conclusion: Whole-body FDG-PET imaging modified the clinical stage in 28% of patients. Moreover, FDG-PET predicted patient outcome with a higher predictive accuracy than CI. This superior prognostic accuracy was achieved with a single FDG-PET study vs. 2.9+/-1.2 CI procedures/patient.