Field of Science

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.

Government subsidies for chiropractic education


Source: daryl-cunningham.blogspot.com

The U.S. is having a political debate about college tuition loans.  Everyone seems to be in favor of keeping the loan rates low, but politicians disagree about how to pay for the subsidized rates.  (The interest rate on government-guaranteed loans will double this July, from 3.4% to 6.8%, unless Congress takes action.)

Lost in this fight is any discussion at all about which students - and which colleges - get these subsidies.  Right now, the subsidized loans are available to almost any institution that calls itself a college or university.

But what about institutions that provide a substandard education?  Or worse, what about institutions that educate people in quackery and pseudoscience?  Subsidies to these institutions are worse than useless.  These so-called colleges spread misinformation that will require much more investment to correct, if it is even possible.  Why, to be specific, is the U.S. government subsidizing students to attend chiropractic colleges?

Chiropractic colleges are a relatively new invention, as is the entire profession.  Chiropractic was invented out of whole cloth by D.D. Palmer in the 1890s.  He mistakenly believed that misalignments of the spine, which he called subluxations, caused a vast range of health problems, even infectious diseases.  Over a century later, chiropractic colleges continue to preach this nonsense; here is what Palmer College of Chiropractic says:
"Improper function of the spine due to slight misalignments—called subluxations—can cause poor health or function, even in areas far removed from the spine and spinal cord itself."
Subluxations have never been shown to cause disease. In fact, subluxations of the spine have not even been shown to exist.  Despite the thorough lack of evidence, chiropractors appear to be quite skilled at keeping patients returning for "adjustments" to maintain good health.  I wonder how much time is spent in chiropractic colleges teaching students about the need for regular spinal adjustments? As retired chiropractor Sam Homola wrote recently:
"The only thing unique about chiropractic is its basic definition as a method of adjusting vertebral subluxations to restore and maintain health....  The subluxation theory has been the chiropractic profession’s only reason for existence since its inception in 1895."
I wonder, too, if chiropractic colleges educate their students about the risk of stroke from their treatments. The rapid head-twisting move that many chiropractors use, which produces a startling cracking sound in the neck, also carries a small but real (and frightening) risk of tearing one of the arteries in the neck.  Chiropractors dispute this claim, but studies have shown that patients with vertebral tears are much more likely to have recently visited a chiropractor.  A systematic review of the evidence in 2010 concluded
"Numerous deaths have occurred after chiropractic manipulations. The risks of this treatment by far outweigh its benefit."
On top of their dubious educational programs, chiropractic colleges pay their presidents astonishingly high salaries, as documented recently in the Chronicle of Higher Education, which pointed out that
"the presidents of chiro­practic colleges are taking in some of the biggest paychecks in higher education." 
For example, the president of Logan College of Chiropractic, which has a budget of $24.5 million, earned $791,418 in 2009.  That's the same salary earned by the president of CalTech, which has a budget 100 times larger.

Low-cost student loans provide a benefit to many students and their universities.  But we don't need to subsidize erroneous and misguided colleges that teach their students nonsense.  If Congress is going to extend the student loan program, they should take this chance to make the program far more selective.  Helping students get a good education helps the country.  Lending students money to learn pseudoscience does just the opposite.