A functional dynamic scoring model to elucidate the significance of post-induction interim fluorine-18-fluorodeoxyglucose positron emission tomography findings in patients with Hodgkin's lymphoma

Abstract

The findings of interim fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET/CT) predict progression-free survival of patients with Hodgkin's lymphoma. Historically, the assessment was based on a static all-or-none scoring system. However, the clinical significance of any positivity in interim FDG-PET/CT has not been defined. Ninety-six patients with Hodgkin's lymphoma who underwent interim FDG-PET/CT were evaluated using dynamic and visual scores, employing mediastinal or liver blood pool uptake as a comparator. FDG-PET/CT was prospectively defined as positive if any abnormal F(18)FDG uptake was present. In a retrospective analysis dynamic score 0 indicated resolution of all disease sites; score 1 defined a single residual focus; score 2 denoted a reduction in the number of foci; score 3 defined a reduction in intensity with no reduction in number; and score 4 indicated no change in the number and intensity of foci or appearance of new foci. The dynamic visual score review reduced the number of positive interim studies from 24 to 6 if a score of 2 or less was considered negative, with significantly better specificity (96%) as compared to static visual scores (78%-86%). The 5-year progression-free survival and overall survival rates in patients who had a negative dynamic score were 92% and 97%, respectively; the corresponding figures for patients with positive results were 50% and 67%. A dynamic visual score may be a better indicator for tailoring therapy than static visual scoring.