Should modest elevations in prostate-specific antigen, International Prostate Symptom Score, or their rates of increase over time be used as surrogate measures of incident benign prostatic hyperplasia?

Author(s): Schenk JM,  Hunter-Merrill R,  Zheng Y,  Etzioni R,  Gulati R,  Tangen C,  Thompson IM,  Kristal AR

Journal: Am J Epidemiol

Date: 2013 Sep 1

Major Program(s) or Research Group(s): CCOP, COPTRG, PUCRG

PubMed ID: 23813705

PMC ID: PMC3755644

Abstract: Although surrogate measures of benign prostatic hyperplasia (BPH) are often used in epidemiologic studies, their performance characteristics are unknown. Using data from the Prostate Cancer Prevention Trial (n = 5,986), we evaluated prostate-specific antigen (PSA), International Prostate Symptom Score (IPSS), and their rates of change as predictors of incident BPH. BPH (n = 842 cases) was defined as medical or surgical treatment or at least 2 IPSS of 15 or higher. Proportional hazards models were used to measure the associations of baseline PSA, IPSS, and their velocities over 2 years with BPH risk, and time-dependent receiver-operating characteristic curves were used to measure their discriminatory performance. Unit increases in PSA, IPSS, and IPSS velocity were associated with 34%, 35%, and 29% (all P < 0.001) increases in BPH risk, respectively. The areas under the receiver-operating characteristic curves were significantly greater than 0.5 for PSA (0.58, 95% confidence interval (CI): 0.56, 0.60), IPSS (0.77, 95% CI: 0.75, 0.78), and IPSS velocity (0.63, 95% CI: 0.61, 0.65); however there were no cut points at which sensitivity and specificity were both above 75%. We concluded that moderate elevations in PSA, IPSS, or their rates of change should not be used as surrogate measures of incident BPH.