Why have a PSA test?
Posted by medconsumers on June 17, 2011
A new review of all clinical trials involving the treatment of early-stage prostate cancer with radiation therapy was published online first by Annals of Internal Medicine and funded primarily by the Agency for Healthcare Research and Quality. It is yet-another example of the inadequacy of the current state of medical knowledge about how to treat early prostate cancer. The trials in this review compared different forms of radiation therapy and/or different doses of radiation. But the review authors bemoaned the lack of trials comparing radiation therapies with watchful waiting—that is, no treatment until symptoms develop.
Two earlier clinical trials (one conducted in Sweden and the other in the U.S.) compared watchful waiting (WW) with radical prostatectomy and came up with mixed results click here. The possibility that WW is better than any treatment has lingered ever since and remains a valid choice for men with early prostate cancer. Don’t take my word for it, see what heads the list of options at the National Cancer Institute website click here. Uncertainty will continue because no head-to-head comparison study has compared all treatment options with WW.
An obvious question comes to mind about the widespread use of the PSA (prostate-specific antigen) screening blood test: Why search for early prostate cancer in symptom-free men when leaving it untreated is reasonable? It is well documented in autopsy studies of older men who died of other causes that most prostate cancers remain dormant. It is also well established that all prostate cancer treatments hold the possibility of severe complications like incontinence, sexual dysfunction, and bowel injury, just to name a few. Prostate cancer kills about 32,000 American men yearly, but the PSA can’t accurately determine whether an early prostate cancer will remain dormant or become life-threatening.
Two trials sought the definitive answer to the question of whether regular PSA screening saves lives; both were published in the same 2009 issue of the New England Journal of Medicine and the results were contradictory. One (U.S. trial) found no lifesaving benefit but lots of harm. And the other (European) found a modest reduction in prostate cancer mortality which came at the great cost of overtreatment: Out of every 1,400 men given PSA screening tests regularly for ten years, one man avoided death from prostate cancer and 48 healthy men were treated unnecessarily for a form of prostate cancer that would never have become symptomatic or life-threatening.
PSA Screening: A brief history
As recently as 1990, there wasn’t much research devoted to the treatment of prostate cancer. It was (and still is) an elderly man’s disease; and “who cares” was the general attitude about a disease that was typically diagnosed at age 75. Surgery was the usual way it was treated … but only after symptoms appeared. Then, in the late 1980s, the PSA (prostate-specific antigen) blood test was introduced as a screening test to find the disease “early” in symptom-less men. Till then, the PSA test was administered only to detect recurrences in men already treated for prostate cancer. And who was behind the expanded use of the PSA? The companies that make the ultrasound machines and biopsy “guns” to diagnose prostate cancer and the drugs that might prevent prostate cancer recurrence (I read this in the N.Y. Times in 1993).
In time, research would show that the PSA isn’t accurate when used as a screening test. But an industry had already begun to build around this usage. Hospitals, for example, offer free PSA screening, seemingly as a good will gesture to the community but also a great way to drum up future customers. The list of treatment options expanded to include different forms of radiation therapy, cryotherapy, and androgen-deprivation therapy. Watchful waiting might be offered, but it did not catch on. Studies showed that most men, even when fully informed of the lack of evidence for the superiority of treatment, opted to be treated because they just couldn’t live with the knowledge of having an untreated cancer.
Some doctors were initially skeptical about PSA screening, but most eventually seemed to fall in line. Malpractice concerns, no doubt. And if any man had doubts about PSA as a lifesaver, they were alleviated by celebrity survivors like General Norman Schwarzkopf and Mayor Rudolph Giuliani who think their lives were saved by the PSA and had multiple opportunities to publicly attest to the wisdom of their respective treatment choices.
If a great many lives were saved as a result of all this early-detection activity, we should know it by now. But in fact there is not only a small decrease in the U.S. prostate cancer death rate but also a large increase in the number of men diagnosed with the disease. And just to make things more complicated, an equivalent drop in prostate cancer mortality has also been shown in countries that do not offer PSA screening tests. click here
What to do
Think twice about having a screening PSA. Consider all options prior to accepting the test. And make sure your doctor doesn’t include it in the routine blood test without your knowledge. At best (the European trial), the chance of being treated unnecessarily as a result of PSA screening is 48 times higher than the chance of avoiding death from prostate cancer. At worst (the U.S. trial), men are treated unnecessarily and no prostate cancer deaths are avoided.
Maryann Napoli, Center for Medical Consumers©