Cost-effectiveness of the use of positron emission tomography in the detection of recurrence of differentiated thyroid cancer

The positron emission tomography (18FDG-PET/CT) was recently introduced in Brazilian health care for many oncology indications but accompanied by higher costs. In our study we performed a cost-effectiveness analysis of the addition of PET/CT to the conventional diagnostic work-up to detect recurrent differentiated thyroid cancers. The analytical decision model represented a hypothetical cohort of adults, thyroid cancer patients with high risk by initial stratification, submitted to total thyroidectomy and ablation with I131. The addition of PET/CT was applied to subjects with negative results on I131scintigraphy. The model was designed from the perspective of the Brazilian public health care system, with a time horizon of 10 years. Effectiveness was measured by the additional recurrent cases detected. Only direct medical costs were considered. Costs and benefits were discounted by 5%. Univariate deterministic and probabilistic sensitivity analyzes were performed to explore the uncertainties. The PET/CT diagnosed 13 additional cases compared to conventional strategy (1,888 vs 1,875) by a cost of R$477,633.05 per case detected. The parameters of greatest impact in the sensitivity analysis were the accuracy of conventional tests, cost of PET/CT and the discount rate. The costs of adding PET/CT seems significant and its introduction is not cost-effective on the Brazilian perspective.