WebMD Health News
Daniel J. DeNoon
Laura J. Martin, MD
May 24, 2012 -- Don't get the PSAprostate-cancer screening test, a U.S. expert panel says. Do get it, many urologists and patient advocates say.
What's a man supposed to do? To provide clarity amid the controversy, here's WebMD's FAQ.
PSA is prostate specific antigen. It's a molecule specific to the cells that make up the male prostate gland.
Prostate cancer disrupts prostate cells and causes the release of PSA into the blood. A simple blood test can measure blood levels of PSA.
The PSA test originally was developed as a way to tell whether prostate cancer was coming back in men already treated for prostate cancer.
But the higher a man's PSA level, the more likely it is he has prostate cancer. Since PSA levels begin to rise early in the course of prostate cancer, the PSA test can detect prostate cancer before it becomes dangerous.
With the PSA test in hand, doctors began giving the test to healthy men with no symptoms of prostate cancer. By 1991, routine PSA screening became widespread in the U.S. -- a year before the start of the first large clinical trial designed to see if PSA screening actually saved lives.
No. PSA blood levels go up for other reasons besides cancer.
As men age, their prostate glands tend to enlarge. An enlarged prostate -- the condition known as benign prostatic hyperplasia or BPH -- may cause high PSA levels. So can infection of the prostate, a condition called prostatitis.
Other things that affect the prostate -- a digital rectal exam, urine retention, or even ejaculation -- can also cause a rise in PSA.
In the U.S., doctors usually get suspicious when a PSA level is 4.0 ng/mL. But studies show that many men with levels well above 4.0 ng/mL do not have cancer. And many men with prostate cancer have PSA scores well below this level.
There are a lot of ways to tweak the PSA test to try to get better results. For example, PSA comes in two forms, free and attached. BPH and other non-cancer conditions tend to increase the free form, while cancer tends to produce more of the attached form. Measuring free vs. attached PSA may help determine whether a prostate biopsy really is necessary, but more research is needed.
Similarly, measuring how fast PSA goes up over time (PSA velocity) or the relationship between PSA and the size of the prostate (PSA density) may help identify men at higher risk of cancer. But without more research, these measures remain controversial.
Advanced prostate cancer is a terrible disease. Every year, some 30,000 U.S. men die of prostate cancer.
The obvious benefit of PSA screening is that it can detect prostate cancer in its early, curable stages.
For the PSA test to save one man's life from prostate cancer, 1,000 men must be screened.
The PSA test itself is done on blood taken during a routine physical exam, at very little risk to a patient.
Men with suspicious PSA levels may go on to have a prostate biopsy. This is done with a needle; usually about a dozen small "cores" are taken. It's unpleasant, but usually uneventful. Even so, about 70 out of 10,000 biopsies result in infection, bleeding, or urinary difficulties.
Men found to have prostate cancer -- about 25% to 35% of men biopsied -- have a number of options.
One is to closely watch the cancer to see if it gets worse. In this case, the harm is anxiety and possibly waiting too long to get treatment.
But in the U.S., most men opt for one of the various effective treatments for prostate cancer. These treatments are very effective at curing the cancer. But they have a high rate of side effects. Men sometimes are left impotent and/or incontinent.
For every 1,000 men who undergo PSA screening, one will develop a blood clot in his legs or lungs due to treatment, two have heart attacks due to treatment, and up to 40 suffer impotence or incontinence.
After comparing those harms to the benefit of saving one life, the U.S. Preventive Services Task Force calculated that the harms of PSA screening outweigh the benefits.
Once prostate cancer is detected, doctors try their best to determine whether the cancer is dangerous. But the truth is in many cases, nobody knows for sure.
Here's what some of the experts say:
Susan G. Fisher, PhD, professor and chair of preventive medicine at the University of Rochester, N.Y.: "Right now we do not have an accurate marker to identify people who have prostate cancer that could eventually cause serious problems for them."
Otis Brawley, MD, chief science officer of the American Cancer Society: "It is very well accepted that 40% to 60% of localized prostate cancers that we cure are in men who did not need to be cured."
Barnett S. Kramer, MD, MPH, director of the office of disease prevention at the National Institutes of Health: "Unfortunately right now we are left with diagnosing a large number of people without precise enough knowledge to spare those who don't need to be treated from treatment."
But a healthy man who is told he has cancer no longer feels like a healthy man. In the U.S., most such men will seek treatment.
The U.S. Preventive Services Task Force is an independent agency. It's made up of experts in preventive or family medicine who serve a four-year term on the panel.
Their recommendations are made for primary-care doctors. Many doctor groups that establish guidelines for patient care use the USPSTF recommendations. Agencies that fund health care -- Medicare and private insurers -- often set their policies based on USPSTF recommendations.
Health care reform -- the Affordable Care Act -- will require Medicare and insurance plans to cover preventive services recommended by the USPSTF. However, they may choose to cover preventive services not recommended by the USPSTF.
Because the USPSTF did not recommend PSA screening -- in fact, the panel recommended against it -- Medicare is not forced to pay for the screening tests.
That's up to the Department of Health and Human Services. And this week, after the USPSTF report came out, HHS Secretary Kathleen Sebelius said Medicare would continue to pay for PSA screening for men who want it.
No private insurer was required to cover PSA screening before the USPSTF recommendation.
Even under the Affordable Care Act, private insurers will not be required to cover PSA testing. Whether they will continue to cover it remains a question.
Maybe, and maybe not. But don't decide until you have a serious talk with your doctor.
The American Cancer Society's chief medical officer, Otis Brawley, is no fan of PSA screening. But he heartily endorses the ACS's advice to men: Discuss the benefits as well as the harms of PSA screening with your doctor, then decide for yourself.
After skin cancer, prostate cancer is the most diagnosed and most treated cancer in the U.S.
It's a big business. But WebMD discussed the USPSTF recommendation with doctors who strongly support PSA screening -- experts who are not in it for the money. They've seen men die painfully from prostate cancer. That kind of experience, psychologists say, influences opinion much more than statistics.
The same kind of process is at work in men treated for prostate cancer. These men strongly believe that the suffering they underwent saved their lives. Again, this kind of experience has a more powerful effect than the statistical knowledge that most of these men would never have died of their cancer.
SOURCES:National Cancer Institute web site: "Prostate-Specific Antigen (PSA) Test."MedicineNet web site: "Prostate Specific Antigen."USPFTF email communication.USPSTF Bulletin, May 21, 2012Chou, R. Annals of Internal Medicine, Dec. 6, 2011.Barnett S. Kramer, MD, MPH, director, office of disease prevention, National Institutes of Health.Otis Brawley, MD, chief science officer, American Cancer Society.Susan G. Fisher, PhD, professor and chair of community & preventive medicine, University of Rochester, N.Y.Anthony D'Amico, MD, professor and chief of genitourinary medicine, Brigham and Women's Hospital, Boston.Michael LeFevre, MD, MSPH, co-chair, USPSTF task force; professor and vice chair, department of family medicine, University of Missouri.
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