Friday, October 14, 2011
PSA redux: The USPSTF finally recommends NOT getting it!
The US Preventive Services Task Force (USPSTF), the independent group of physicians and scientists who make recommendations to the government, medical community, and American people on the value of screening tests, recently came out with a new recommendation on the use of laboratory tests for Prostate Specific Antigen (PSA) in screening for prostate cancer. It recommended AGAINST it --in their terms, a “D” recommendation. Previously, USPSTF had recommended against PSA screening for men over the age of 75, but had not taken a position for or against screening in younger men (an “I” recommendation, insufficient evidence to recommend for or against screening).
My belief is that this is a good, appropriate, and very overdue recommendation which will come as no surprise to those who have read this blog for some time. I, and guest authors, have addressed this issue several times (PSA Screening: What is the value?, Mar 21, 2009; PSA Screening: “One of Medicine's Great Success Stories"?, Oct 27, 2009 (by Robert Ferrer);, Men’s Health? Women’s Health? Valid screening opportunities or “Hallmark Holidays”?, Mar 15, 2011). In addition I have often linked to and cited the work of Kenny Lin, MD, who writes the Common Sense Family Doctor blog, and resigned from the Agency for Healthcare Quality and Research (AHRQ) as a member of the USPSTF support team in November, 2010, over his perception that these recommendations were being delayed by political considerations. Dr. Lin has also written about PSA testing often (including "It is time to stop this [PSA] June 21, 2011, PSA testing: will science finally trump politics? Feb 28, 2011) and has recently addressed the new recommendations on Oct 7, 2011, Shannon Brownlee on the pros and cons of early cancer screening.
Of course, a lot of people do not think that this recommendation is a good thing. Two large groups, in particular, oppose the new recommendations: urologists and others who earn their livings treating prostate cancer and “advocacy” groups, supported by many high-profile (as well as just regular folks) men who have survived prostate cancer. Many of these men are quoted in Gardner Harris’ NY Times article “US panel says no to prostate screening for healthy men”, October 7, 2011. One of those who is quoted (actually not in the published NY Times piece, but in another version of Harris’ article published in the Seattle Times, is my colleague Brantley Thrasher, MD, Chair of the Department of Urology at the University of Kansas Medical Center, who said, "It appears to me that screening is accomplishing just what we would like to see: diagnose and treat the disease while it is still confined to the prostate and, as such, still curable."
I like Brant Thrasher, I think he is a good and knowledgeable doctor and great surgeon, but I strongly disagree with him on this one. As much as we would like, and believe me as a family doctor I would like, and Kenny Lin would like, a test that could find disease early while it was still curable and make a difference in people’s live, PSA is not that test and, at this point prostate cancer is not that disease. These are two separate issues, so let’s take them separately.
PSA is not a good test. Yes, it is often, maybe usually, elevated in men with prostate cancer. Of course, in some men with prostate cancer it is not above the “normal” cutoff. This has led some advocates of PSA screening to suggest use of “PSA velocity”: check it yearly and watch the rate of rise rather than the absolute value. But the bigger problem for PSA as a screening test is that it is often elevated in men who do not have prostate cancer but just have a big prostate (“hypertrophy”, almost universal in men above a certain age), or even DO have cancer, but the very-slow-growing-that-is-not-going-to-kill-you-before-you-die-of-something-else kind, which is by far the most common variety. These men are subjected to ultrasounds, biopsies, and treatments that cause significant morbidity (impotence, incontinence of urine, and “radiation proctitis” of the rectum and anus, developing congestive heart failure from hormone treatment, to name a few) with no benefit. Baylor physician and panel chair Virginia Moyer notes in the Times article that “This test cannot tell the difference between cancers that will and will not affect a man during his natural lifetime. We need to find one that does.” In 2010, Richard Ablin, PhD, who discovered the a prostate specific antigen (but not the PSA test) in 1970, called use of the test “a public health disaster” and “not much better than a coin toss.” (“The Great Prostate Mistake”, NY Times, March 9, 2010.
But the bigger issue is that there is no good evidence that treatment of any kind – surgical, radiation, hormonal – makes any difference in the outcome of prostate cancer. Surgeons like Brant Thrasher think it does, and he may be some day proven correct , at least in some circumstances, currently there is much more evidence supporting that it doesn’t than that it does. If you have the common, less-aggressive kind of prostate cancer, you won’t die from it, with or without treatment. If you have the rarer, highly-aggressive kind, you will probably die from it, with or without treatment. The Times article notes that “…advocates for those with prostate cancer promised to fight the recommendation. Baseball’s Joe Torre, the financier Michael Milken and Rudolph W. Giuliani, the former New York City mayor, are among tens of thousands of men who believe a P.S.A. test saved their lives.” They may believe it, but they are probably (I obviously don’t have access to their medical records) wrong. The test diagnosed prostate cancer, they were treated for prostate cancer, and they are alive. QED. But it’s false logic, an association that doesn’t demonstrate cause. If they are alive now, they would be alive (at least as far as the prostate cancer is concerned) without the treatment. And they wouldn’t have those “little” problems like incontinence and impotence that seem like a small price to pay for not dying of cancer, but are a big price if the treatment didn’t make any difference. The famous folks who have died of prostate cancer, like Frank Zappa, died despite treatment.
The Times quotes Thomas Kirk, of Us TOO, the nation’s largest advocacy group for prostate cancer survivors, saying “The bottom line is that this is the best test we have, and the answer can’t be, ‘Don’t get tested.’” He’s wrong. That is the answer. We not only need a test that can distinguish the “bad” kind of prostate cancer that will kill you from the kind that probably won’t, we need treatments that evidence shows makes a difference in survival and quality of life if you do have the bad kind. In the meantime, getting tested is likely to create more harm than benefit.