Prostate Cancer Intervention Versus Observation Trial: economic analysis in study design and conditions of uncertainty.

The Prostate Cancer Intervention Versus Observation Trial (PIVOT) compares radical prostatectomy with palliative expectant management of patients with clinically localized prostate disease. As with all clinical trials, several of the assumptions underlying PIVOT are characterized by uncertainty. Economic analysis has the potential to clarify some of these important issues, thereby guiding study design and interpretation and enhancing the clinical usefulness of the findings. One important uncertainty about the trial relates to the true clinical state of potentially eligible patients. While clinical examination is an insensitive method by which to stage prostate cancer, several diagnostic tests, such as bone scanning and magnetic resonance imaging with rectal coil, are more accurate but more expensive. Another issue is whether to start the trial with the screening of patients or at the time of prostate cancer diagnosis. Economic analysis can assess these trade-offs between study cost and validity. A second potential role for health economics is in dealing with the considerable uncertainty surrounding the study's findings and conclusions and their interpretation. While the stated primary outcome of the trial is survival, a multidimensional outcome (particularly one that incorporates factors of survival, quality of life, and cost) is likely to be more clinically relevant in the prostate cancer population, given the only modest improvements in survival hypothesized for radical prostatectomy. To develop such a measure, quantitative assessment of patient preferences is required, in addition to the measures currently included in the study. Assessment of costs of care are important, given the large and growing size of the study's target population.(ABSTRACT TRUNCATED AT 250 WORDS)