Prostate cancer screening: PSA (Prostate Specific Antigen) Testing

Prostate cancer is common in men. About 1 in 6 men (16%) will develop prostate cancer at some point in their lives. Events during Men’s Health Month often encourage men to be screened for prostate cancer. In the recent past cancer screening was recommended to include prostate-specific antigen (PSA) testing and a digital rectal examination (DRE). This post will focus on PSA testing and, next time, the DRE.

The test for a “prostate specific antigen” was developed in the 1970s and approved by the FDA in 1986 as a method to monitor the progress of cancer treatment or the recurrence of prostate cancer. Heralded as a screening breakthrough, PSA testing was FDA approved for screening purposes in 1994 and since then an estimated 1 billion PSA tests have been performed. However recent research has quelled some of the enthusiasm of this screening test.

Prostate cancer is common, and while about 16% of men develop identifiable disease, autopsies show that upward of 60% of men over 80 have evidence of unrecognized “disease,” but have died of other causes. It is becoming increasingly clear that prostate disease is slow to progress and may not present a threat to life.

The prostate-specific antigen is a normal product of prostate function. It is increased in a number of circumstances other than cancer such as benign prostatic hypertrophy (BPH) and prostatitis. PSA is also elevated post-ejaculation and may be affected by bike riding. Elevated PSA has been shown to precede identification of disease by 10-15 years. So elevated PSA identified at screening may indicate many things other than cancer.

The positive predictive value of elevated PSA, that is the number of men with a high PSA who actually have cancer, is about 30%. Evidence from randomized clinical trials, observational, and modeling studies have tried to evaluate the effectiveness of PSA screening to prevent death from prostate cancer. Overall, screening of men at ordinary risk of prostate cancer results in only small reductions in mortality.

Any medical procedure involves a balance of risk and benefit. The risks associated with prostate cancer screening include overdiagnosis, risks of biopsy, and risks of treatment.

Overdiagnosis is detection of conditions such as a slow-growing prostate cancer that will not cause serious disease or death. The associated harms are caused by further diagnostic procedures such as biopsy, unnecessary treatments and their side effects for cancers that are unlikely to cause death, and the psychological impacts of being “diagnosed with cancer.”

Prostate biopsy often is performed in follow up for elevated PSA. Biopsy bears the real risk of infection, bleeding and other complications in addition to the discomfort and anxiety that the procedure often entails.

Treatment of prostate cancer can be very effective in ideal circumstances and has been life-saving for many men. However, many men diagnosed with prostate cancer can have years of problem-free life. Interventions commonly proposed include surgical removal of the prostate (prostatectomy) and radiation.  Both of these procedures, while usually effective for cancer, do involve high rates of erectile dysfunction, urinary and bowel incontinence, and pain. So treatment of otherwise benign prostate “cancer” can produce a lifetime of trouble.

High-risk individuals may benefit from enhanced screening. Increased risk may be indicated by a family history of prostate cancer, a previous history of prostate cancer, and men who have the genetic risk factors of the BRCA1 or BRCA2 gene mutations.

Given the uncertainty of PSA screening of men at average risk for prostate cancer and the potential for untoward side effects of further testing and treatments for cancer, it is important that men and their caregivers make informed decisions about screening.  This is where integrative health (IH) providers can have an impact. While PSA testing and prostate cancer treatment may be outside the scope of practice for some IH clinicians, the personal and powerful relationships that most IH providers engender with their patients creates an ideal environment for information sharing and can set the stage for informed decision-making.