Primary staging of lymphomas: cost-effectiveness of FDG-PET versus computed tomography

The objective of this study was to measure the incremental cost-effectivene ss of 2-(fluorine-18) fluorodeoxyglucose positron emission tomography (FDG- PET) versus computed tomography (CT) as diagnostic procedures in the primar y staging of malignant lymphomas. The study was based on 22 patients of a c linical study who underwent the diagnostic procedures at Ulm University Hos pital between April 1997 and May 1998. Direct costs of FDG-PET and CT, incl uding staff, materials, investment, maintenance and overheads, were valued using a micro-costing approach. The effectiveness of both diagnostic proced ures was measured as the percentage of correctly staged patients, given a g old standard for staging. The incremental cost-effectiveness ratio was the main outcome measure. Costs per patient of FDG-PET were 257 euros for FDG p roduction and 704 euros for the FGD-PET scan, thus totalling 961 euros (in 1999 prices). The cost per patient of CT scans was found to be 391 euros, V erified PET findings induced an upstaging in four patients such that the ef fectiveness was 81.8% (18/22) for CT and 100% (22/22) for PET. Incremental cost-effectiveness ratios (interpreted as the additional costs of a more ef fective diagnostic strategy per additional unit of effectiveness, i.e. addi tionally correctly staged patient, achieved) were 478 euros per correctly s taged patient for CT versus "no diagnostics" and 3133 euros for FDG-PET ver sus CT. Great potential for cost saving was identified in sensitivity analy ses for FDG-PET. It is concluded that diagnostic accuracy and the costs of the diagnostic procedures could be measured precisely. FDG-PET was more acc urate than CT. Decision-makers who consider savings in treatment costs sign ificant may find the cost-effectiveness ratio of PET to Lie within an accep table range. However, more research is needed to assess the long-term treat ment and cost effects of more accurate staging. There is significant potent ial to improve the technical efficiency of PET.