BENEFITS VS. RISKS
Prostate-specific antigen (PSA) screening can be used to detect prostate cancer. However, much debate centers around whether PSA testing reduces deaths or results in overdiagnosis and overtreatment. Observational studies suggest a positive relationship between PSA screening and decreased prostate cancer mortality.3,4 Recent evidence indicates that active treatment of clin-ically localized prostate cancer may result in decreased mortality.5,6
However, the European Randomized Study of Screening for Prostate Cancer showed that screening resulted in only a 20% relative reduction in prostate cancer deaths at 9 years. Additionally, 1,410 men would need to be screened and 48 men treated to prevent one prostate cancer death over 10 years.7 The Prostate, Lung, Colon, and Ovary Trial of the National Cancer Institute found no difference in prostate cancer deaths between screened and nonscreened patients at 7 to 10 years.8
In May 2012, the U.S. Preventive Services Task Force (USPSTF) issued a recommendation against screening men of any age for prostate cancer based on the small, at best, potential benefit and demonstrated harms. Of 1,000 men screened, two to three de-velop a serious complication of treatment, such as blood clot, heart attack, stroke, or death. About 30 to 40 in 1,000 develop infection, erectile dysfunction, or urinary incontinence.9
WHO SHOULD BE SCREENED
The 2010 American Urological Association’s Prostate-Specific Antigen Best Practice Statement: 2009 Update states that candidates with an anticipated lifespan of 10 years or more should undergo baseline PSA testing at age 40 years along with a digital rectal examination (DRE).10 Results from three studies show that combined DRE and PSA screening is better at detecting prostate cancer than either test alone.11 A history should be taken, as other diseases may affect PSA values. However, the USPSTF now recommends that men not be screened unless they previously received a prostate cancer diagnosis.
MEASURING PSA LEVELS
Patients with prostate cancer often have lower free/total PSA ratios while men with benign disease have higher free/total ratios. Using this ratio may reduce the number of prostate biopsies. A PSA level of 4.0 ng/mL or higher is typically defined as high. Techniques such as age-adjusted PSA can improve the sensitivity of screening.12
The PSA level and the rate at which it is rising correlate with the extent and potential for prostate cancer. The average man older than 50 years with a normal DRE has a 10% risk of biopsy-detectable prostate cancer if his PSA level is 0.0 to 2.0 ng/mL. The likelihood rises to 15% to 25% if the PSA level is 2.0 to 4.0 ng/mL, 17% to 32% if the PSA level is 4.0 to 10.0 ng/mL, and 43% to 65% if the PSA level is above 10.0 ng/mL.13
PSA testing has led to earlier diagnosis of prostate cancer and declining prostate cancer mortality. However, because testing can cause more harm than benefit, decisions to undergo testing should be individualized and the risks and benefits should be thoroughly discussed with patients. JAAPA
Mary Hewett is assistant professor, Division of Physician Assistant Studies, Medical University of South Carolina, Charleston, and the department editor for When the Patient Asks. The author has indicated no relationships to disclose relating to the content of this article.
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