| Positron Emission Tomography (PET) using 18 F-fluorodeoxyglucose ( 18 F-FDG) is a developing nuclear imaging technique, which has been introduced in the management of malignant lymphoma. A multicenter prospective cohort study has been started in 2002 to assess the value of midtreatment FDG PET for early prediction of treatment outcome in terms of freedom from tumour progression in patients with aggressive NHL treated with CHOP chemotherapy. FDG-PET was performed after the third cycle of chemotherapy. 114 patients were included of which 95 were evaluable. PET after 3 courses was negative in 45 patients and positive in 50. 48% of PET positive patients progressed or relapsed as compared to 22% of PET negative patients. Median progression free survival (PFS) for PET positive versus PET negative patients was 19.8 months versus not yet reached (p=.0087). In a multivariate analysis, IPI and PET were independent predictors for PFS. These results corroborate and extend the evidence that mid-treatment FDG-PET is highly predictive for PFS and may be a useful tool for risk-adapted management of aggressive NHL. The second study about PET response and clinical scores in relapsed lymphoma was set up in collaboration with the University Medical Center Groningen to demonstrate whether prognostic classification based on the secondary age-adjusted international prognostic index (sAA-IPI) for relapsed aggressive Non-Hodgkin Lymphoma (NHL) or the prognostic score for relapsed Hodgkin's lymphoma (HL) can be improved by including the mid-treatment results of fluorine-18-fluorodeoxy-glucose positron emission tomography (FDG-PET). Clinical data of relapsed lymphoma patients who were treated with second-line chemotherapy (DHAP-VIM-DHAP) followed by autologous stem cell transplantation (ASCT) were collected and combined with the results of FDG-PET performed before and after two cycles of re-induction chemotherapy. Both secondary clinical risk score (p<0.001) and FDG-PET-response (p<0.001) were independent predictive factors for the total evaluable group of lymphoma patients and for NHL patients alone. The combined use of the clinical risk score and FDG-PET response after two chemotherapy courses identified at least four categories of patients with a failure free survival varying between 100%-5% post-transplantation (p<0.001). These data indicate that the secondary clinical risk score in conjunction with FDG-PET response provides a more accurate prognostic instrument for the outcome of second-line treatment in at least relapsed NHL patients. |
