Fused FDG-PET/contrast-enhanced CT detects occult subdiaphragmatic involvement of Hodgkin's lymphoma thereby identifying patients requiring six cycles of anthracycline-containing chemotherapy and consolidation radiation of spleen.

BACKGROUND Spleen and liver assessment for occult involvement of Hodgkin's lymphoma (HL) challenges current staging procedures. PATIENTS AND METHODS We prospectively evaluated event-free survival (EFS) in 103 HL patients staged with fused 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET)/contrast-enhanced computed tomography (CT) to identify those at greatest risk for abdominal relapse. The EFS of this series was compared with that of a historical cohort of 100 HL patients staged with separate FDG-PET and diagnostic CT acquisitions. RESULTS Thirty-one of the 103 patients staged with FDG-PET/contrast-enhanced CT were found to have spleen involvement and 10 patients liver involvement, whereas 14 of the 100 patients staged with separate procedures were found to have spleen involvement and 3 patients liver involvement. There were significantly more intensive treatments (six courses of anthracycline-containing chemotherapy and spleen radiation) in the fused PET/CT group than in the historical cohort (P ≤ 0.04). At a median follow-up of 27 months, five events occurred in the fused PET/CT group (HL relapse, 4 patients; carcinoma, 1 patient) and 19 events in the historical cohort (HL relapse, 18 patients; acute promyelocytic leukemia, 1 patient). Ten of the 18 relapses in the historical cohort were localized in the spleen and/or liver area. None of the four relapses in the fused PET/CT group was localized below the diaphragm. Thus, FDG-PET/contrast-enhanced CT-guided treatment resulted in a 95% EFS, whereas separate FDG-PET and diagnostic CT-guided treatment resulted in an 81% EFS (P = 0.002). CONCLUSION FDG-PET/contrast-enhanced CT is an accurate frontline single imaging diagnostic tool enabling effective tailored treatment in HL patients.