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Yield of Screening in a Large U.S. Prostate Cancer Screening Trial

In the PLCO trial, many of the men who had elevated PSA levels or suspicious DRE results did not undergo biopsy.

The PLCO trial is an NIH-sponsored cancer screening trial that began in 1993. To evaluate prostate cancer screening, researchers randomized 76,000 men (age range, 55-74) to annual prostate-specific antigen (PSA) tests and digital rectal exams (DREs) or to no screening (at least within the trial). Although the key clinical outcome (prostate cancer mortality) will not be reported for several years, researchers have published two reports on the yield of initial screening in 34,000 men.

During the first round of screening, 8% of men had suspicious DRE results, 8% had elevated PSA levels (>4 ng/mL), and 14% had abnormal results on one or both tests. Of 4801 men in the latter group, 1510 (31%) underwent prostate biopsy within a year, and cancer was diagnosed in 556 (1.6% of the entire cohort). After 3 years, the cumulative biopsy rate was 64% among men with elevated PSA levels at baseline screening and 50% among those whose PSA levels became abnormal during the next three rounds of screening. The likelihood of undergoing biopsy was higher with elevated PSA levels and lower with older age.

Comment: These reports provide a snapshot of initial screening in the highly publicized PLCO trial. Perhaps the most interesting finding is that many patients with positive screening tests did not undergo biopsy. The trial design does not include a diagnostic or treatment algorithm; rather, screen-positive patients are referred to private physicians for further management. The investigators defend this study design as reflecting typical community practice, in which clinicians weigh various factors before recommending biopsy. However, urology researcher Patrick Walsh criticizes this aspect of the study in editorial comments that follow the Journal of Urology paper. He expresses concern that some men in the trial are not being managed appropriately and that, therefore, the final results of this long-awaited trial will be inconclusive.

— Allan S. Brett, MD

Published in Journal Watch General Medicine April 12, 2005

Citation(s):

Andriole GL et al. Prostate cancer screening in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial: Findings from the initial screening round of a randomized trial. J Natl Cancer Inst 2005 Mar 16; 97:433-8.

• Original article (Subscription may be required)
• Medline abstract (Free)

Pinsky PF et al. Prostate biopsy following a positive screen in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. J Urol 2005 Mar; 173:746-51.

• Medline abstract (Free)