Prostate-specific antigen testing practices and outcomes

Abstract

Objectives: To characterize prostate-specific antigen (PSA) testing practices in a hospital-based primary care clinic, and to determine the outcomes of PSA testing, including urology referrals, biopsies, cancers detected, and cancer treatments.

Design: Retrospective cohort study. Data were obtained from computerized Department of Veterans Affairs (VA) files and the statewide New Mexico Surveillance, Epidemiology, and End Results (SEER) tumor registry.

Setting: Primary care clinics in a university-affiliated VA Medical Center.

Patients: Subjects were 1,448 men without cancer undergoing PSA testing in 1993 with follow-up through 1994.

Main results: Twenty-one percent of clinic enrollees at least 40 years of age were tested with PSA, including 58 who were 75 years of age or older. By the end of 1994, 40.0% (95% confidence interval [CI] 37.2%, 42.8%) were retested; 25.6% (95% CI 21.7%, 29.5%) of initial retesting occurred within 6 months. Overall, 20.7% (95% CI 18.9%, 22.5%) of PSA tests in the cohort were for men aged 75 years or older and were repeated within 6 months. Among the 193 subjects with PSA values > or = 4.0 ng/mL, 86.0% (95% CI 81.1%, 90.9%) were followed-up in urology clinic, and 46.1% (95% CI 39.1%, 53.1%) underwent biopsy. Only 11 of 51 men aged 75 years or older who were referred to urologists for an elevated PSA underwent biopsy. Forty cancers were diagnosed-a detection rate of 2.8% (95% CI 2.0%, 3.6%). Of these, 28 were organ-confined, 7 had regional invasion, and 3 had distant metastases.

Conclusions: Primary care providers frequently ordered PSA tests, but a substantial proportion of testing occurred outside recommended age ranges and screening intervals. Older patients with elevated PSA values often did not complete diagnostic workups. Better adherence to screening guidelines may limit the number of both PSA tests and urology referrals.