Predictive value of early 18F-fluoro-deoxyglucose positron emission tomography in chemosensitive relapsed lymphoma

F-18-fluoro-deoxyglucose (FDG) positron emission tomography (PET) might be a better tool than computerized tomography (CT) in predicting long-term treatment outcome in patients with relapsed chemosensitive lymphoma who are candidates for autologous stem cell transplantation (ASCT). We studied patients with recurrent or persistent aggressive non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), who were treated with three courses of second-line induction chemotherapy [DHAP-VIM (dexamethasone, cytarabine, cisplatin followed by etoposide, iphosphamide and methotrexate)-DHAP], followed by myeloablative therapy and ASCT if chemosensitive. FDG-PET was performed in parallel to conventional diagnostic methods before starting, and after two courses of, second-line therapy. Of 68 relapsed lymphoma patients, 46 chemosensitive patients (33 NHL and 13 HD) were included, of whom 39 were transplanted. After DHAP-VIM, the second PET scan was normalized in 15/46 patients; progression-free survival at 2 years was 62% for PET-negative patients versus 32% for PET-positive patients (P = 0.048). The relative risk for progressive disease in patients with <90% intensity reduction was 2.85 (95% confidence interval 1.15-7.05, P = 0.018). Early FDG-PET may help to predict the long-term treatment outcome of ASCT in chemosensitive patients with relapsed lymphoma and identify those patients who need extra or alternative treatment. Disappearance or >90% reduction of intensity of abnormal FDG uptake after two courses of reinduction therapy was correlated with a favourable outcome.