The Need to Conduct Future Resarch on the Benefit of the Prostate Specific Antigen Screening Test Using Value of Information Framework

Abstract

Prostate cancer (PC) is the second most common cancer in men throughout the world and is the second leading cause of cancer deaths in men in the United States. Screening for PC is routinely conducted through the prostate specific antigen screening test (PSA); unfortunately, PSA levels change due to a variety of factors which make the threshold for a normal PSA level difficult to ascertain in all populations. Professional organizations and task forces differ with their recommendations for PSA screening. This study examined the amount of research that should be funded in order to clarify uncertainty associated with PSA screening. The value of information (VOI) framework utilizes net monetary benefit to determine the amount of funding that should be allocated to a specific field of research in order to reduce uncertainty. Using the VOI framework, this research examined the: 1) expected value of information (EVI); 2) population expected value of information (pEVI), a population-specific estimate by race and age group; and 3) expected value of perfect information (EVPI). Men were identified as having at least one PSA screening exam from the 2000-2007 SEER-Medicare dataset. A Cox Proportional Hazard model and phase-based costing were used to determine costs and survival increments. Bootstrapped replicates were generated and the net monetary benefit was calculated. VOI estimates were calculated from the replicates. Sensitivity analyses captured change under different willingness-to-pay (WTP) thresholds. The matched analytic cohort contained 180,692 PC cases and controls. Among cases, 36.2% of cases had at least one PSA test and 59.1% of controls had at least one PSA test. PSA testing resulted in an additional 0.9835 life-years (359 life-days). The mean incremental cost between the two cohorts was $1,880. Using a WTP threshold of $50,000, the EVI was $518,233 and the EVPI was $616,463. The population estimate was $8,281,979 for African Americans (AA), $46,525,105 for Caucasians, $22,657,186 for men aged 65 to 74, and $24,558,627 for men aged 75+. Estimates obtained for EVI and EVPI were lower than comparable cancer screening VOI estimates. Given results based on population estimates, future research funding for PSA screening among Medicare beneficiaries should focus on Caucasians and AA.