Publication: The Role of Post-treatment FDG-PET/CT Scanning after the First-line Chemotherapy in Predicting Prognosis in Patients with Hodgkin Disease and High-grade Non-Hodgkin Lymphoma: A Comparative Study with Clinical Prognostic Risk Scoring Data
Objective: We aimed to evaluate the role of fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) performed after the first-line therapy in predicting prognosis of lymphomas and compare the results with the pretreatment prognostic risk scoring (PRS) indices.
Methods: One hundred three patients with histopathologically confirmed Hodgkin (HD) and high-grade non-Hodgkin lymphoma (NHL) were included in the study. All patients received FDG-PET/CT imaging after the end of primary treatment. After intraveneus application of FDG, whole body PET/CT from the upper thigh to the vertex was performed.
Results: The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of post-treatment FDG-PET/CT imaging in predicting remission status were 73.6%, 91.6%, 88%, 66.6%, and 94.0%, respectively. Those values were 63.0%, 62.0%, 62.0%, 27%, and 88.0% respectively, for pretreatment clinical risk scoring (p<0.001). Among the patients with positive PET scans after ending of the first-line therapy, 71.4% of those with only single lymph node station involvement stayed in remission, whereas 12.5% of the patients who had involvement of multiple lymph node stations and 16.7% of the patients who had extranodal disease could sustain in remission (p<0.05).
Conclusion: We found that FDG-PET performed after first-line therapy was superior to clinical PRS systems in predicting prognosis of HD and NHL disease as conclusions. Although it was more successful to predict patients who would stay in remission with its high NPV, FDG-PET/CT imaging had a lower PPV due to false positive results. However, persistent FDG uptake in multinodal lymphatic stations and/or in extranodal sites on the post-therapy PET/CT scanning was more suggestive in predicting risk for recurrence.