Guys: you don't need a PSA test for prostate cancer

Graphic depiction of risk without or with PSA tests, from
the Harding Center for Risk Literacy.

I learned a new word this week: pseudoepidemic. That's what happens when people start looking really hard for a disease that didn't get much attention earlier, and then–not surprisingly–the disease suddenly becomes much more prevalent.

This is precisely what happened with prostate cancer in the early 1990s, just after screening tests for prostate-specific antigen (PSA) became widely available. As explained by NIH's Paul Pinsky and colleagues in an article in the New England Journal of Medicine this week, prostate cancer rates rose from 135 (cases per year, per 100,000 men) in 1988 to 220 in 1992, a 63% increase in just four years. Rates slowly dropped after that, but they remained above 150 through 2009.

No one believes that this increase represented an actual increase in the rate of prostate cancer. Instead, it was an increase in the rate of diagnosis, made possible by the PSA test. After this simple blood test became available, millions of men started getting routine PSA testing. The idea was that, because prostate cancer increases the levels of PSA in the blood, this test could detect cancer early, which in turn would save lives.

It hasn't worked out that way. The problem is that, as a large body of evidence has now shown, most prostate cancers are slow-growing, "indolent" tumors that don't kill you, at least not before something else does.

What's worse is that the treatments for prostate cancer have very serious, life-altering side effects. 20-30% of men treated with surgery and radiation suffer from long-term incontinence, erectile dysfunction, or both.

This is especially problematic given that the false-positive rate of PSA testing is as high as 80%. In other words, if your doctor tells you that your test was positive, there's an 80% chance that you don't have cancer. Many men, though, elect for further, much more invasive testing after a positive result, because who can sleep at night without knowing for certain?

But how about the benefits of early detection? Alas, they did not materialize. Very large trials (including the PLCO study, with over 75,000 participants) showed that routine PSA screening did not prevent any deaths. The only study to show any benefit, ERSPC, had serious flaws, as explained by Ian Haines and George Miklos in the Journal of the National Cancer Institute.

Putting all these facts together, the US Preventative Services Task Force concluded that the harms of PSA testing substantially outweigh the benefits, and it recommends, bluntly:

"Do not use prostate-specific antigen (PSA)-based screening for prostate cancer."

The American Academy of Family Physicians agrees, stating:

"There is convincing evidence that PSA-based screening leads to substantial over-diagnosis of prostate tumors. Many tumors will not harm patients, while the risks of treatment are significant. Physicians should not offer or order PSA screening unless they are prepared to engage in shared decision making that enables an informed choice by patients."

Even the American Urological Association, which strongly opposed the USPSTF recommendation when it first appeared, now recommends against PSA screening except in one age group, men 55-69 years old. The AUA, though, is highly biased in favor of testing, because its members make significant income from PSA tests and the subsequent follow-ups.

Prostate cancer is a very serious disease among older men. According to the American College of Physicians, 1 out of 16 men will receive a diagnosis of prostate cancer in their lifetimes, although only 2.9% will die of it, most of them older than 75. Nonetheless, PSA screening does not help: it carries a significant risk of harm. In this week's NEJM article, Pinsky et al. conclude:

"Under the `first do no harm principle,' it seems reasonable to forgo mass screening as a public health policy at this point."

Someday we may have a better test for prostate cancer, but for now, we don't. If your doctor offers you a PSA test, your best response is probably to tell him no thanks.

[Aside: the article in the New England Journal of Medicine was written by scientists from the National Cancer Institute at NIH, yet it's behind a paywall that prevents anyone from reading it without paying a costly fee or an even more expensive subscription to the journal. Why do we have to pay a fee to read work that the taxpayers already paid for?]

The PSA test for prostate cancer: more harm than good?

Millions of men are tested each year for high levels of prostate-specific antigen, or PSA, which is designed to detect early signs of prostate cancer. The test is covered by insurance, so most men readily agree to it. After all, what's the harm?

Well, plenty. PSA screening, we now know, "leads to a substantial overdiagnosis of prostate tumors." Many of these cancers grow very slowly, and men with slow-growing prostate tumors may never have symptoms. However, once a man is told he has cancer, there is a a strong tendency to treat it, and treatment has serious, often harmful side effects: 20-30% of men treated with surgery and radiation will have long-term incontinence and erectile dysfunction.

There is a furious debate going on right now over the evidence for and against PSA screening. The debate started with a large-scale US study called PLCO, which found no benefit from annual PSA screening. Soon after that, the US Preventive Services Task Force recommending that most men should not get regular PSA tests.  They concluded:

"Many more men in a screened population will experience the harms of treatment than will experience the benefit.... The USPSTF concludes that there is moderate certainty that hte benefits of PSA-based screening for prostate cancer do not outweigh the harms."

The American Academy of Family Physicians agrees, and has adopted a clear recommendation:

"Don't routinely screen for prostate cancer using a prostate-specific antigen (PSA) test or digital rectal exam."

which I wrote about last November.

In contrast, the American Urological Association responsed to the USPSTF report by issuing a statement that it was "outraged and believes that the Task Force is doing men a great disservice." Prostate surgery is big business for urologists, which may have biased their reaction. However, to their credit the AUA modified its guidelines on PSA screening, which now state

"The [AUA] Panel does not recommend routine screening in men between ages 40 to 54 years at average risk."

For men ages 55 to 69, they recommend "shared decision-making," but they still insist that there is a benefit for men in this group. Their 2013 press release says "the highest quality evidence for screening benefit was in men ages 55 to 69 screened at two- to four-year intervals."

Why does the controversy continue? One reason is that a large European study, called ERSPC, reported a small benefit from PSA screening. The European study is actually a combined analysis of 7 studies in 7 countries, each of which was run a bit differently.  Five of the studies reported no benefit, and just two, from Sweden and the Netherlands, showed a benefit.

So what was going on in those two countries? Did they do screening differently, or treatment differently? Well, it seems they did. In a letter published in Uro Today on May 6, Ian Haines and George Miklos lay out an explanation: in the Swedish study, many more patients in the control group (the group that did not receive PSA screening) were treated with androgen deprivation therapy, ADT, which recent evidence indicates may increase the risk of death. Haines and Miklos published a more detailed analysis last October, accompanied by an editorial by Otis Brawley, the Chief Medical Officer of the American Cancer Society.

Brawley pointed out that

"the harms of screening have been consistently demonstrated in all screening trials to date."

He calls for "an objective panel of experts with access to all of the data" to address the controversy over the possible bias in some of the European trials. Carlsson et al. responded last month in the Journal of the National Cancer Institute, defending their methods, but Haines and Miklos fired back in the same issue, arguing that the benefits found in the European study "rests entirely on the ... Goteborg trial from a single city.

Regardlesss of the evidence from that one city, though, the evidence today is strong that until we have much better treatments for prostate cancer, routine screening with PSA tests causes more harm than good. The side effects of surgery can be life-altering and devastating. Guys: unless you have a special reason to be concerned about prostate cancer, tell your doctor "no thanks" if he offers you a PSA test at your next checkup. That's what I did.

Guys: no more invasive prostate cancer exams!

Good news for all the over-40 men out there: we don't need routine screening for prostate cancer. More to the point, we don't need to subject ourselves to the dreaded "digital rectal exam" that has been a standard procedure for decades.  (Sorry for the ick factor, but that's what it's called, and yes, "digital" does mean "finger", not "computer.")   Most guys don't need any encouragement to avoid this particular invasive procedure, but now there's good scientific evidence saying we don't need it.

One of the most widely used screens for prostate cancer is the PSA test. I wrote about this last year, after several studies and a thorough review concluded that

“there is moderate certainty that the benefits of PSA-based screening for prostate cancer do not outweigh the harms.” (USPSTF, Annals of Internal Medicine, 22 May 2012)

Now, the Choosing Wisely campaign and the American Academy of Family Physicians (AAFP) have included not only PSA testing, but also digital rectal exams as procedures that are usually unnecessary. Their advice to physicians is very clear:

Don’t routinely screen for prostate cancer using a prostate-specific antigen (PSA) test or digital rectal exam.

So guys, the next time you go to the doctor, don't let him (or her) give you the PSA test (it's expensive too! even if insurance pays for it) or the dreaded "digital rectal exam." If your physician hesitates (though I imagine most doctors will be glad to skip these tests), print this list and hand it to him. If you or your doctor want to know more, the list includes references to long, detailed summaries of the evidence.

It's not just prostate cancer screening that is wasteful and unncessary. After a review of the latest evidence, the AAFP, as part of the Choosing Wisely campaign, has identified 15 tests and procedures that most of us should just say "no" to.

Choosing Wisely, which was created by the American Board of Internal Medicine Foundation, is a great idea: a campaign to educate patients and physicians about what practices are:

• Supported by evidence
• Not duplicative of other tests or procedures already received
• Free from harm
• Truly necessary

The AAFP has identified their first set of 15 unnecessary procedures. Widespread attention to this list may save a huge amount of time and expense, and it should improve public health. Choosing Wisely and the American College of Medical Toxicology have also looked at homeopathy and other quack-y "complementary" or "integrative" treatments. Not surprisingly, their advice is simple: don't use them. (See Respectful Insolence for much more on that topic.)

Those fish oil supplements might cause cancer

Eating fish is good for you, especially fish that contain omega-3 fatty acids.  So I was surprised last week to read a new study in the Journal of the National Cancer Institute that found that omega-3 fatty acids increase the risk of prostate cancer.  The risk for both high-grade and low-grade cancer was increased with higher levels of omega-3 fatty acids.  This is a carefully done study, and the results should make anyone who is taking fish oil pills reconsider.

One reason this study caught many people off guard is that there has been much evidence showing that a diet rich in fish that contain omega-3 oils is good for you.  The Mayo Clinic says that  "eating fish helps your heart", especially fish like salmon that contain omega-3 fatty acids.  The American Heart Association (AHA) elaborates:

"Omega-3 fatty acids benefit the heart of healthy people, and those at high risk of — or who have — cardiovascular disease. Research has shown that omega-3 fatty acids decrease risk of arrhythmias (abnormal heartbeats), which can lead to sudden death. Omega-3 fatty acids also decrease triglyceride levels, slow growth rate of atherosclerotic plaque, and lower blood pressure (slightly)."

This all sounds great.  Because of the evidence about the benefits of fatty fish, supplement manufacturers have been marketing and selling fish oil pills for years, with great success.  As I described back in 2010, GlaxoSmithKline even created a high-dose omega-3 fatty acid pill called Lovaza that has FDA approval.

But the evidence for that you can get the same benefit from supplemental omega-3 fatty acids — taking a pill, that is — is much weaker.  In fact, a large review published last year in the Journal of the American Medical Association found no connection at all between supplemental omega-3 and a lower risk of heart attacks, strokes, or death in general.  Other studies have reported similarly negative results.  So it appears that fish oil pills may not have any heart benefits.

And now, with this new study, we learn that supplemental fish oil might increase the risk of prostate cancer.

The bottom line: the AHA recommendations about eating fish are probably still good ones.  The AHA website says:

"We recommend eating fish (particularly fatty fish) at least two times (two servings) a week. Each serving is 3.5 oz. cooked, or about ¾ cup of flaked fish.  Enjoy fish baked or grilled, not fried." 

But popping a fish oil pill is not going to cut it. As we've seen before, supplements often fail to show the benefits that a healthy diet offers.  So save your money and stop buying those fish oil pills — and fire up the grill and throw on a few salmon fillets for this weekend's barbecue.

Do we all need PSA tests?

Say your doctor offers to run a PSA test, which might detect early signs of prostate cancer.  The test is free to you, because insurance covers it.  And you're already getting a blood test to measure cholesterol, so the cancer test doesn't involve any extra pain.  Why not?  And by the way, the American Urological Association recommends regular PSA screening for all men over 40.  Based on this information (or less), millions of men get a PSA test every year.

But hold on.  Suppose your doctor tells you a different story.  First he explains that a recent, large-scale US study looked at the effect of annual PSA screening on more than 75,000 men, and found no benefit at all.  A separate large study in Europe showed a very small benefit, but only in 2 of the 7 countries participating in the study.  Suppose your doctor also explained that if you have a positive PSA test, there's an 80% chance that it will be false - that you won't have cancer.

Suppose your doctor also explained that "PSA-based screening leads to a substantial overdiagnosis of prostate tumors" and that treatment usually requires surgery.  The effects of treatment are serious: 20-30% of men treated with surgery and radiation suffer from long-term incontinence and erectile dysfunction.

Prostate cancer tends to grow so slowly that many men with prostate cancer should not be treated at all.  Unfortunately, once someone knows he has cancer, there's a very good chance he will elect treatment, even though we can't really tell if treatment will help.

Do you still want a PSA test?  Do you want one every year?

Well, after a thorough review of the evidence from multiple trials, the US Preventive Services Task Force recommended a few weeks ago that men not get PSA screening for prostate cancer.  They concluded:

"there is moderate certainty that the benefits of PSA-based screening for prostate cancer do not outweigh the harms." (USPSTF, Annals of Internal Medicine, 22 May 2012)

This recommendation, although based on a thorough assessment of risks and benefits, was met with howls of protest from urologists, who conduct most of the prostate cancer screening and treatment in the U.S. and elsewhere.  The American Urological Association stated bluntly:

"The AUA is outraged and believes that the Task Force is doing men a great disservice by disparaging what is now the only widely available test for prostate cancer, a potentially devastating disease."

The AUA also issued press releases and launched a lobbying effort, asking their members to contact the media and Congress.  They even provided a sample letter for urologists to send to their representatives in Congress.

Unfortunately for the AUA, their responses contain a very slanted presentation of the facts.  The AUA president's response emphasizes the studies that found a benefit for PSA testing, but ignores those that found no benefit.  In addition to this cherry-picking, they make the misleading claim that the recent U.S. PLCO study found "a significant reduction of prostate cancer death rates," which it did not.  In fact, the PLCO study found a higher death rate from prostate cancer in men who received PSA testing.
And the AUA statements ignore the very serious risks of prostate surgery; essentially they are pretending the risk is zero.

Why did the urologists react so strongly?  The answer appears to be simple: money.  Urologists make a lot of money on prostate cancer treatments. The USPSTF estimated that in the first 20 years of PSA testing, 1 million additional men were treated as a result of screening.   And if the surgery is unnecessary, you don't get a refund.  

So who are you going to believe?  The Preventive Task Force report presents a thorough review, laying all the details on the table.  Their members don't make a profit from prostate surgeries.  Their report simply more credible than the knee-jerk reaction from the urologists' association.  I'll let the Task Force have the last word:

"The harms of PSA-based screening for prostate cancer include a high rate of false-positive results and accompanying negative psychological effects, high rate of complications associated with diagnostic biopsy, and—most important—a risk for overdiagnosis coupled with overtreatment. Depending on the method used, treatments for prostate cancer carry the risk for death, cardiovascular events, urinary incontinence, erectile dysfunction, and bowel dysfunction. Many of these harms are common and persistent." 

At my last checkup, my doctor asked if I wanted a PSA test.  I told him no thanks.