When the U.S. Preventive Services Task Force recommended in October 2011 that men not get routine PSA screening for prostate cancer, many men were surprised and angry—similar to the way women felt two years earlier when new mammogram guidelines were released. PSA stands for prostate specific antigen, a protein produced by prostate cells and released into the blood.
Even though the PSA blood test can detect cancer early, it saves few, if any, lives and often leads to treatments causing serious complications, according to the draft guidelines from the Task Force. It concluded that the substantial risks of screening outweigh the benefits, which are small at most, and thus the PSA test should be discouraged. Note: The guidelines focus only on routine screening, not the use of PSA in men with symptoms or signs of prostate cancer or for its use to monitor cancer treatment. Also, the financial costs of testing and treatment were not considerations in the analysis.
For most American men who have had PSA tests—and especially the two million who have been told they have cancer based on results of screening and subsequent biopsies—this was probably a shock. But actually it wasn’t something out of the blue. Three years ago, the Task Force advised against routine PSA tests for men over 75 for the same reasons and, reportedly, it was ready to recommend against routine screening for all men, period. But fears of a backlash (from patients, urologists and politicians) led it to call for more analysis of the data and to postpone the release of the new guidelines.
The value of PSA screening has actually always been questioned. The Task Force has never recommended it, though until now it just said there was insufficient evidence to recommend for or against it for men age 50 to 75. In 2010 the American Cancer Society stopped advising routine screening and urged more caution; it now simply tells men to talk to their doctors about it. Urological and prostate cancer advocacy groups, which have been boosters of screening, are most vocal in disagreeing with the Task Force’s recommendations.
How can a simple early-detection test for cancer not automatically be a great thing?
ABCs of PSA
The prostate, a gland between the bladder and rectum in men, produces seminal fluid. Cancer of the prostate is the second most commonly diagnosed cancer in men (after skin cancer) and the second leading cause of cancer deaths in men (after lung cancer).
The unusual thing about prostate cancer is that the great majority of tumors—especially in older men—remain small, develop very slowly or not at all, do not spread and cause no symptoms. It’s estimated that 1 in 6 American men will be diagnosed with prostate cancer, and 1 in 36 will die from it—meaning that it is fatal in about 15 percent of diagnosed cases. Thus, far more men die with prostate cancer than from it. In fact, autopsy studies reveal that one-third of men in their forties and fifties and three-quarters of those over 85 had prostate cancer—usually small and harmless—and never knew they had it (they died from something else).
Age greatly increases the risk of prostate cancer—about 85 percent of cases are diagnosed in men over 60, and 70 percent of deaths occur after age 75. Having a brother or father with prostate cancer more than doubles the risk. Black men are 60 percent more likely to develop it than whites, and twice as likely to die from it. Nevertheless, the Task Force did not recommend screening for black men or those with a family history, for lack of evidence of benefit.
The PSA test merely measures the level of this protein in the blood, not cancer. PSA levels rise as a result of prostate disorders—such as infection, benign enlargement or cancer—or sometimes for no apparent reason. The test, which is easy to do and inexpensive, was introduced in the 1980s to monitor men already diagnosed with prostate cancer. But doctors soon began using it to screen healthy men.
Unfortunately, PSA is not a very good screening test. The only way to determine which men have cancer is with a biopsy. Only about 20 to 30 percent of men with elevated PSA turn out to have cancer. (There is debate about what cutoff points should be used to define “elevated” and “normal” PSA.) Moreover, a similar percentage of men with prostate cancer have PSA levels in the “safe” range.
Though experts have proposed ways to improve the interpretation of PSA results—such as assessing PSA level in relation to prostate size and monitoring PSA changes over time—there is still no way to predict with any certainty which low-grade cancers will become aggressive and spread and which will cause no problems.
The biopsies can cause anxiety, pain and, more rarely, infection. But the biggest concern is that abnormal biopsy results usually lead to the treatment of small, slow-growing cancers that would never have become life-threatening—treatment that often has serious adverse effects. (The Gleason score is used to grade the aggressiveness of cancer cells, but more research is needed to determine how much its use reduces mortality rates and overtreatment.) Surgery to remove the prostate and radiation are standard; both treatments often produce erectile dysfunction, urinary problems, incontinence and/or other complications.
Another problem: Choosing a treatment is often confusing, since there is no one “best” option. For older men, “watchful waiting” (or “active surveillance”) rather than treatment is often advised. Studies comparing watchful waiting to surgery or radiation therapy have yielded conflicting results.
Why the drop in death rates?
The good news is that death rates from prostate cancer have been declining since 1990. Some researchers attribute the improvement to PSA testing, though this is debated, since better treatments may deserve most of the credit. But if PSA screening is largely responsible, it’s surprising that studies have been unable to resolve the debate about it.
Even data suggesting that screening saves lives present a sobering picture. According to some estimates, for every man whose life is prolonged because of PSA screening, somewhere between 30 and 100 men end up being treated for a cancer that was never going to harm them. One-third to one-half of those treated will have adverse effects like erectile dysfunction and urinary incontinence. And about 1 in 200 men die from complications of prostate surgery. Many men with faster-growing prostate cancer will die from it even if PSA screening detects it early and they are treated for it.
What to do
We do not recommend routine PSA screening—that is, all men should not be automatically tested. The decision is a personal one, and men should discuss the pros and cons of PSA testing with their doctors starting at about age 50, earlier if they are at high risk. Keep in mind, if you decide to be screened, no one knows what screening intervals or PSA thresholds are optimal. Even if you are screened periodically, you should stop at age 75, since further testing is very unlikely to prolong lives.
Studies have shown that when the pros and cons of PSA testing are fully described to men who have not yet made up their minds, they are more likely to decide against it. Such patient/doctor discussions will undoubtedly affect a man’s decision about screening far more than advice from the Task Force.
If, after reading our article, you're still confused or undecided about PSA screening, here are some good decision aids. From the American Cancer Society: Helping Patients Make Decisions About Screening. From the Mayo Clinic: Prostate cancer screening: Should you get a PSA test?
In April 2013, the American College of Physicians (ACP) released new clinical guidelines about screening for prostate cancer. These guidelines are similar to our advice, except that ACP advises stopping PSA screenings after age 69. It recommends that "clinicians inform men between the ages of 50 and 69 years about the limited potential benefits and substantial harms of screening for prostate cancer." The decision to do PSA screenings should be based on a man's risk factor for prostate cancer, a discussion of the benefits and harms of screening, his general health and life expectancy and his personal preferences. Screening should only be done for those who "express a clear preference for screening," said the ACP.
Also see Dr. John Swartzberg's personal take on PSA screening and the Task Force's advice.
Originally published January 2012. Updated April 2013.