Role of 18F-FDG-PET/CT Imaging in the Prediction of Prognosis in Patients with Indolent Lymphoma: A Prospective Study (Preprint)

BACKGROUND The role of FDG-PET/CT in indolent lymphoma has been minimally studied. OBJECTIVE The objective of this study was to assess the value of FDG-PET/CT in the prediction of prognosis in indolent lymphoma. METHODS We prospectively recruited 42 patients with indolent lymphomas. Two patients were excluded and 40 underwent a baseline PET/CT and follow up at various time points. Nine patients were observed, 7 received four doses of Rituximab alone, and 24 received chemoimmunotherapy. Metabolic response on follow-up PET/CT was assessed using SUVmax and Deauville criteria (DC). We aimed to obtain the best SUVmax/DC to predict optimal survival rates, risk stratification, and optimize therapeutic strategies. The mean follow-up from initial diagnosis was 33.83 months. RESULTS SUVmax <4.35 at interim PET/CT provided the best discriminator with progression-free survival (PFS) of 100% and median survival time of 106.67 months, as compared to 43.8% and 50.17 months respectively for SUVmax ≥4.35 (P=.041). This cut-off was also valuable in predicting overall survival (OS) at baseline, i.e. 100% OS with baseline SUVmax <4.35, versus 58.4% for SUVmax ≥4.35 (P=.133). OS of patients with baseline DC score <3.0 was 100%, with median OS 106.67 months. CONCLUSIONS We demonstrated the utility of PET/CT in indolent lymphomas. SUVmax (<4.35 vs ≥4.35) at interim PET/CT performed best in predicting PFS. CLINICALTRIAL