Cost-effective therapy remission assessment in lymphoma patients using 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography: is an end of treatment exam necessary in all patients?

Background: The aim of this study was to evaluate the necessity of 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) after end of treatment in lymphoma patients who had an interim FDG-PET/CT. Patients and methods: In 38 patients with Hodgkin's disease (HD) and 30 patients with non-Hodgkin's lymphoma (NHL) interim PET/CT (intPET) after two to four cycles of chemotherapy and PET/CT after completion of first-line treatment (endPET) were carried out. Cost reduction was retrospectively calculated for the potentially superfluous endPET examinations. Results: In 31 (82%) HD patients, intPET demonstrated complete remission (CR) which was still present on endPET. The remaining seven HD patients (18%) had partial remission (PR) on intPET. For NHL, 22 (73%) patients had CR on intPET analysis which was still present on endPET. In the remaining eight NHL patients, intPET revealed PR in seven and stable disease in one patient. None of all intPET complete responders progressed until the end of therapy. Thus, of the 196 PET/CT's carried out in our study population, 53 endPET's (27.0%) were carried out in interim complete responders. Conclusion: End-treatment PET/CT is unnecessary if intPET shows CR and the clinical course is uncomplicated. An imaging cost reduction of 27% in our study population could have been achieved by omitting end of treatment FDG-PET/CT in interim complete responders.