Outcomes/Effectiveness Research

Studies explore appropriateness of PSA testing for prostate cancer

The prostate-specific antigen (PSA) test is used to screen men for prostate cancer. Although the clinical value of the test is still hotly debated, its use has been rising. This relatively costly test may be inappropriately used in many cases, according to two studies supported by the Agency for Healthcare Research and Quality and summarized here. The first study (HS07107) found that 76 percent of PSA tests at one hospital were either performed too frequently or not age-appropriate. The second study (HS08397 and HS09538) showed that during the mid-1990s, primary care physicians' decisions to use PSA tests were not age appropriate.

Poteat, H.T., Chen, P., Loughlin, K.R., and others (2000). "Appropriateness of prostate-specific antigen testing." American Journal of Clinical Pathology 113, pp. 421-428.

Establishing simple limits on patient age and frequency of testing for the PSA test could eliminate 74 percent of inappropriate PSA tests, concludes this study. The researchers identified appropriate criteria for use of the PSA test and used the criteria to evaluate appropriateness of PSA test use on outpatients and inpatients at a university teaching hospital. Appropriate PSA test criteria included assessing prostate cancer progression after therapy, evaluating treatment efficacy during therapy, and monitoring for prostate cancer recurrence two to four times a year. Also, patients 1, 2, or 3 years or more after curative treatment should receive a PSA assay every 3, 4, and 6 months, respectively.

The PSA test should also be used for diagnostic workup and staging for men with signs or symptoms associated with prostate cancer, for men with cancer of unknown primary site, and to establish a baseline value for beginning therapy for benign prostatic hypertrophy with a drug such as finasteride. The researchers viewed as "appropriate but debated" a once-yearly screening of asymptomatic men aged 50 to 75 years. They considered it inappropriate to screen asymptomatic men older than 75 years, asymptomatic men with less than 10 years of life expectancy, asymptomatic men with no risk factors who are younger than 50 years, and men with risk factors before age 40.

Using these criteria, the researchers found that 21 percent of PSAs used for outpatients and 17 percent used for inpatients were inappropriate. Among outpatients, 52 percent of tests were done for screening and 19 percent for monitoring for cancer recurrence. For inpatients, workup for cancer (56 percent) was the most frequent and cancer screening the second (25 percent) most frequent reason for testing. Of tests failing the appropriateness criteria, 76 percent resulted from excessively frequent and age-inappropriate screening. Of the 87 tests considered inappropriate, only 1 test result influenced clinical management of patients younger than 75 years.

Collins, M.M., Stafford, R.S., and Barry, M.J. (2000, February). "Age-specific patterns of prostate-specific antigen testing among primary care physician visits." Journal of Family Practice 49(2), pp. 169-172.

A substantial proportion of PSA testing occurs among men whose age makes them less likely to benefit from screening, concludes this study. Although the 1997 American College of Physicians' clinical guideline states that men aged 50-69 years will benefit most if prostate cancer screening ultimately proves effective, the authors found that primary care physicians (PCPs) used 17 percent of PSA tests on men younger than 50 years, only 50 percent for men aged 50 to 69 years, and fully 33 percent for men aged 70 years and older. The frequency of PSA testing was highest (7 percent) during visits by men aged 60 to 64 years, 65 to 69 years, and 70 to 74 years. It was slightly lower for men 75 to 79 years (6.3 percent) and moderately lower for men older than 80 (3 percent).

These findings suggest that physicians' decisions to screen men for prostate cancer during the mid-1990s did not take into account patients' ages. The rate of PSA testing did not decline substantially until the age of 80. At that age, even use of PSA testing at 3 percent of visits was still high considering the greater risk posed to these elderly men by other potential causes of death, such as stroke or heart attack. These men also are at greater risk from complications related to prostate cancer treatment and have a relatively short time to benefit from these treatments, according to the authors.

Their findings were based on analysis of office visits made by adult men to family physicians, general internists, general practitioners, and geriatricians, which were recorded by the 1995 and 1996 National Ambulatory Medical Care Surveys. The researchers used the data to estimate the probability of a PCP ordering a PSA test during a visit.

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