New Advice About PSA Testing
When the influential U.S. Preventive Services Task Force recommended against routine screening for prostate cancer in 2012, many men were surprised, confused, or even angry. Some men followed the advice and stopped getting screened or didn't start, while others ignored it.
Now the Task Force has changed its collective mind. It has revisited the subject, as it does every five years, and issued new draft guidelines that leave the decision about prostate cancer screening to individual men, ages 55 to 69, depending on their "values and preferences" and in consultation with their doctors.
It still recommends against screening men 70 and older. (Note: Prostate cancer screening means testing men without signs, symptoms, or history of the disease.) The new guidelines align with those of the American Cancer Society, American Urological Association, and American Academy of Physicians, though those groups say the discussion about the pros and cons of screening should begin around age 50 or even 45 and that most men should stop at 75, which is what we have also advised.
Some groups, such as the American Academy of Family Physicians and the Canadian Task Force on Preventive Health Care, still recommend against routine screening.
In some ways, the Task Force is going back to its pre-2012 guidelines, which said there was insufficient evidence to recommend for or against screening.
Why the change?
The test measures blood levels of prostate-specific antigen (PSA), a protein produced by prostate cells. PSA testing has long been a contentious issue because, though it is likely to benefit some men, it's not clear how many lives it actually saves.
Meanwhile, the risks are well known, including overdiagnosis, overtreatment, and the serious adverse effects that treatment may entail. Thus, experts have had difficulty in advising men about what to do.
The Task Force is changing course largely because it now sees the benefit/risk ratio somewhat more favorably. It says that while research is still inconsistent, longer-term follow-up data from a key European study strengthen the case that screening slightly reduces the risk of dying from prostate cancer.
It cites estimates that for every 1,000 screened men (ages 55 to 69) over a 10- to 15-year period, 240 will get a positive PSA result, leading to 100 positive biopsy results and ultimately one or two fewer deaths from prostate cancer.
In addition, the Task Force notes there are now better ways to reduce the potential harms. For instance, improvements in how PSA results are interpreted and utilized allow doctors to better predict which cancers will behave aggressively and spread and which don't need to be treated.
What's more, treatment options are now better and more clearly understood. Notably, recent studies have confirmed that active surveillance (also called watchful waiting) can safely allow most men diagnosed with less-aggressive prostate cancer to monitor it for years without rushing into treatment. More men are now opting for that, reducing the potential harms of unnecessary treatment.
PSA ups and downs
PSA is not a cancer test per se. Blood levels can rise as a result of a variety 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 millions of healthy men.
Even though the PSA test can detect cancer early, that isn't always a good thing. Age greatly increases the risk of prostate cancer—about 90 percent of cases are diagnosed in men over age 55, and 70 percent of deaths occur after age 75.
However, the great majority of prostate tumors, especially in older men, remain small, develop very slowly or not at all, do not spread, and cause no symptoms. Far more men die with prostate cancer than from it. In fact, autopsy studies reveal that more than one-third of men in their 50s and three-quarters of those over 75 had prostate cancer—usually small and harmless—and the vast majority never knew they had it and died from something else.
Unfortunately, PSA is not a very good screening test because it produces lots of false alarms and misses many cancers (since some men with prostate cancer have normal PSA levels).
The only way to determine which men with elevated PSA have cancer is with a biopsy. Fewer than half of them turn out to have cancer. (Newer imaging techniques may improve the accuracy of biopsies.)
Among men who are diagnosed with prostate cancer, the Task Force estimates that up to half have cancer that would never affect their health—this is called overdiagnosis. But abnormal biopsy results often lead to the treatment of small, slow-growing cancers. And standard treatments such as radiation and surgery to remove the prostate often produce impotence, urinary incontinence, and other complications.
The good news is that death rates from prostate cancer have been declining since 1990, and some of this improvement can be attributed to PSA screening, though better treatments probably deserve much of the credit.
But even data showing that screening saves lives present a sobering picture. It's estimated that 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.
Most men treated with radiation or surgery will have potentially serious complications, according to the Task Force. Such numbers are improving, however, thanks to more men opting for active surveillance.
And, of course, some men with fast-growing prostate cancer will die from it even if PSA screening detects it early and they are treated for it.
We agree with the Task Force's new draft recommendation that PSA screening should be a personal decision and that men should discuss the pros and cons with their doctors.
But like the American Cancer Society, we think this should start at about age 50 (not 55, as the Task Force advises), and even earlier for men who are at higher risk. Keep in mind, for men who decide to be screened, no one knows what screening intervals are optimal (some studies suggest once every two to four years if PSA level is low).
Even if they get screened, we think that men can stop at age 75 (not 70), since further testing is unlikely to prolong lives. But this too is a personal decision, based on a man's preferences and overall health.
Ultimately, it's up to you how you want to play the odds, but it should be an informed decision. You may decide to be screened, for example, if you place greater value on finding cancer early, despite the uncertain benefits and known risks. In contrast, you may decide against it if you fear that getting abnormal PSA results will land you on the "slippery slope" of overdiagnosis and overtreatment.
Several organizations and medical groups offer decision aids to help men decide about PSA screening. These include the American Society of Clinical Oncology and the American Cancer Society.
Who's at higher risk?
Besides increasing age, several factors boost the risk of prostate cancer:
- Family history. Having a brother or father with prostate cancer more than doubles your risk (brother more so than father). Your risk is even higher if several of your relatives have had the cancer, especially if they were young when it was found.
- Race. Black men are 60 percent more likely to develop it than white men, and more than twice as likely to die from it.
- Genes. Men who inherit certain genetic mutations (notably of the BRCA gene, best known for increasing the risk of breast and ovarian cancer) have elevated rates of prostate cancer.
Nevertheless, the Task Force does not single out any of these higher-risk groups for screening, saying that more research is needed. Other experts, however, do advise such men to get screened and start earlier.
Doc, let's talk
To make an informed decision about PSA screening, men need to have a balanced discussion about the pros and cons with their doctors or other health care providers. Only a minority of men have such a discussion.
This was seen in a study published online in the journal Urology in March, which looked at a nationwide survey database of 217,000 men. Only 30 percent said that their health care providers discussed both the advantages and disadvantages of PSA screening with them.
Meanwhile, 36 percent of men reported that only the advantages were discussed; 1 percent, only the disadvantages; and 34 percent reported that neither had been discussed. Men who discussed only the disadvantages or who had no discussion about screening were least likely to get the PSA test.
Previous studies have shown that when the pros and cons of PSA testing are fully discussed with men who have not yet made up their minds, they are more likely to decide against it, though this new study did not find that a balanced discussion dissuaded men.
Many doctors include the PSA test in routine blood work without asking, or even telling, their patients. Possible explanations include lack of time during office visits, disinclination to discuss a confusing topic, or doctors' belief that the benefits of screening outweigh the harms.