Purpose: To assess the cost-effectiveness of early prostate cancer detection with a novel prostate cancer detection index* added to serum prostate-specific antigen (PSA) compared with PSA alone test from a managed care organization perspective.
Method: The prostate cancer detection index is a mathematical formula combining Access Hybritech PSA, free PSA, and a PSA precursor form [-2]proPSA, to predict prostate cancer. It is used as an aid in distinguishing prostate cancer from benign prostatic conditions in men with a PSA test result ≥2 or ≥4 ng/mL and nonsuspicious digital rectal exam. A Markov model was constructed to estimate the expected costs and utilities of prostate cancer detection and consequent treatment under four testing strategies in men aged 50 through 75 years. The testing strategies varied in test thresholds (PSA ≥2 or ≥4 ng/mL) and methods (PSA alone vs. PSA plus the index) to recommend a prostate biopsy. The transition probabilities were from the electronic medical records analysis for male members in Kaiser Permanente Southern California (KPSC) during 1998-2007. Health state utilities and prostate cancer treatment costs were derived from the published literature. The model’s cycle length was 1.5 years based on KPSC’s usual practices.
Result: The most cost-effective strategy is to use PSA plus the index at PSA 2-10 ng/mL to estimate the probability of prostate cancer and recommend a biopsy, which has the lowest costs and highest effectiveness [cost/effectiveness (C/E)=13,650/12.416, $1,099/QALY]. Next is PSA plus the index at PSA 4-10 ng/mL [C/E=14,095/12.364, $1,140/QALY), followed by PSA test alone using PSA threshold ≥4 ng/mL [C/E=15,256/12.304, $1,240/QALY), and finally, PSA ≥2 ng/mL [C/E=15,789/12.287, $1,285/QALY). The strategy of PSA plus the index at PSA 2-10 ng/mL displays a 74% to 86% probability of being cost-effective at a willingness-to-pay range of 0 to $150,000/QALY gained. Variables including discount rate, starting or stopping age for PSA screening, and health utility of cancer have the most impact on the model.
Conclusion: From a managed care payer prospective, using the index as an aid to distinguish prostate cancer from benign prostatic conditions at PSA 2-10 ng/mL dominated other strategies, and was optimal in all strategies under the willingness-to-pay of $150,000/QALY. This strategy could be an important method of prostate cancer detection and improving men’s health outcome. *Not currently available in the U.S.