Use of a Decision Analysis Model to Assess the Cost-effectiveness of Fdg Pet Imaging in the Diagnosis and Staging of Isolated

Few data exist on the medico-economic usefulness of Positron Emission Tomography (PET) in the management of metachronous liver metastases from colorectal cancer. The study was designed to assess the cost-effectiveness of PET in the diagnosis and staging of patients with metachronous liver metastases of colorectal cancer using a decision analysis model. Methods: Two alternatives were compared: computed tomography (CT), and computed tomography associated with PET (CT + PET). Transition probabilities were estimated from published data and consultations with experts. Survival data were provided by the Burgundy digestive cancer registry (France). Costs of imaging techniques and treatments were assessed using reimbursements from the French health care insurance for the year 2004. Evaluation criteria included incremental cost-effectiveness ratios (ICERs) and the proportion of unnecessary operations avoided in patients without metachronous liver metastases. Results: CT associated with PET was the most cost-effective strategy, presenting an expected incremental cost saving of 2,671 € per patient, for the same level of expected effectiveness as CT alone (1.88 years life expectancy per patient). Sensitivity analyses performed on epidemiological and economic parameters showed that this model was robust. The model also suggested that CT + PET could avoid exploratory surgery for 6.1% of patients, i.e. 88.4% risk reduction compared to CT alone. Conclusion: PET for diagnosis and staging does not generate additional survival effectiveness compared to CT alone. However cost savings associated with its use and the improvement of therapeutic management justify therefore its generalization in clinical practice. Key-words; Positron-Emission Tomography, metachromous metastases, decision modeling, cost-effectiveness, program evaluation.