Economic evaluation studies in nuclear medicine: the need for standardization

The guidelines for publishing economic evaluations require a statement of t he economic importance of the analysis and the viewpoint from which it has been carried out, as well as specification of at least two alternative prog rammes or interventions, the form of economic evaluation, the outcome measu re, the method of costing, the time horizon and adjustment for timing of co sts and benefits (e.g. by a discount factor), and the allowance for uncerta inties (e.g. by implementation of a sensitivity analysis). The decision ana lysis can be based on clinical trial data, on retrospective or administrati ve databases, or on modelling. The choice of outcome measures is the key is sue in an economic evaluation. In cost-effectiveness analysis, benefits are usually measured in natural units. This is the form of economic evaluation most frequently used in nuclear medicine. Endpoints of effectiveness appli ed in studies in this field have been procedures avoided, procedures initia ted, cardiac events, survival probability, morbidity, quality of life and p rotracted or failed surgical procedures. In other instances, surrogate endp oints have been used such as metastases detected, staging, viability or tum our response. This, however, limits comparability of cost-effectiveness con siderably, as proof of a change in the health outcome cannot be obtained. M easures of utility such as QALYs (quality-adjustled life years) have so far only been applied for decision tree analysis. Useful examples of economic evaluation studies in nuclear medicine are presented here for fluorodeoxygl ucose positron emission tomography (FDG-PET) in the preoperative staging of non-small cell lung cancer, for FDG-PET in differentiating indeterminate s olitary pulmonary nodules, for somatostatin receptor scintigraphy in detect ing metastases of carcinoid tumours, for routine preoperative scintigraphy with sestamibi in patients with parathyroid adenoma, for periodic measureme nt of thyroid-stimulating hormone in detecting mild thyroid failure, for di agnostic algorithms including a lung scan in patients with suspected pulmon ary embolism, for myocardial perfusion imaging as an incremental prognostic factor in patients with coronary artery disease, and for the use of radioi odine as first-line therapy of Graves' hyper-thyroidism and of toxic nodula r goitres. Further evaluations of effectiveness or utility should be carrie d out within a multidisciplinary framework to ensure that nuclear medical p rocedures are included in the general management guidelines.