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Prostate Screening

February 13, 2003 at 12:00 AM EST
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JIM LEHRER: Finally tonight, prostate cancer. Television evangelist Pat Robertson’s announcement today that he had it, was the second by a prominent American in the last few days. We have a report on new questions about screening for prostate cancer. The reporter is Susan Dentzer of our health unit, a partnership with the Henry J. Kaiser Family Foundation.

SUSAN DENTZER: When Democratic Sen. John Kerry of Massachusetts announced this week that he’d been diagnosed with prostate cancer, he credited a popular screening test, the so-called PSA, for tipping him off to the presence of disease.

SEN. JOHN KERRY: I hope all men will recognize the critical, the importance of being able to have that screening, certainly at age 50 and over, being able to follow up whenever there is that differential that is noticed, and take steps as I’ve been able to very rapidly to try to deal with it.

SUSAN DENTZER: Evidently many U.S. men feel the same way, since millions undergo similar screening tests every year. So it took many by surprise when a government advisory group issued this statement last December: “The evidence is insufficient to recommend for or against routine screening for prostate cancer.”

The group, the U.S. Preventive Services Task Force, reviewed all major previous studies of PSA tests and another common screening tool, the digital rectal exam. Based on that review, the task force said it had found good evidence that screening “can detect prostate cancer in its early stages.”

But on the other hand, the panel said it could not find reliable evidence from medical studies that screening led to fewer prostate cancer deaths.

It also noted that screening sometimes led to unnecessary treatment, such as for small cancers that did not necessarily pose a danger to patients; it said that treatment for cancer could also lead to serious side effects, or even death. As a result, the task force said there was no way of determining whether the benefits of screening outweighed the possible harms.

That inconclusive verdict on the value of prostate cancer screening has rekindled the debate that has been playing out for years. On one level, screening it’s a socioeconomic issue: Is it worthwhile for individuals, health insurers or the government to spend hundreds of millions of dollars on screening if the evidence is so uncertain that it really saves lives? On another level, it’s also a personal issue: Should an individual man undergo screening for prostate cancer, and if so, why, and when?

Understanding the debate requires some knowledge about the prostate, a small, walnut- size gland located just below the male bladder. We spoke with Dr. Patrick Walsh, a prominent prostate cancer surgeon at Johns Hopkins University Medical Center. He performed surgery on Sen. Kerry earlier this week.

DR. PATRICK WALSH: Many men don’t know they have a prostate until they have a problem from it because it has no important physiological function. Although it does provide some of the fluid, the seminal fluid, it does not appear to be important for reproduction. The prostate really doesn’t do anything except cause trouble.

SUSAN DENTZER: That trouble can include infections, benign enlargement of the gland or, in the worst cases, cancer, especially as men age. In fact, about one in six U.S. men will develop prostate cancer over their lifetimes — and for unknown reasons, that rate climbs to one in three for African-American men.

An estimated 221,000 U.S. men, half of them 75 or older, will be diagnosed with some form of prostate cancer this year. About 29,000 will die, making prostate cancer the second deadliest cancer in men, after lung cancer. Dr. Andrew von Eschenbach is head of the National Cancer Institute, and he was diagnosed with and treated for prostate cancer himself several years ago. He says there are a variety of different types of the disease.

DR. ANDREW VON ESCHENBACH: It really is a family or spectrum of disease. On one end of the spectrum, many men develop a form of prostate cancer that’s quite benevolent. They can live their entire lives and it never creates a problem.

On the other end of the spectrum, there are men who have a very virulent form of prostate cancer that can, in fact, become lethal, and, as I indicated earlier the second leading cause of death for men.

SUSAN DENTZER: At its worst, the cancer spreads beyond the prostate and into the bones, often causing a painful and protracted death. And because there are many different types and degrees of cancers, there are multiple treatment options as well.

DR. ANDREW VON ESCHENBACH: For some men whose disease is very small, very early in its development, and very benevolent in its behavior, they may not require any aggressive intervention, whereas for other men whose disease is much more extensive and has the potential to be much more aggressive, they may require interventions with options such as surgery to remove the entire cancer, or radiation therapy to sterilize the disease.

SUSAN DENTZER: And as with most medical treatments, all of these options carry with them the risk of side effects, including impotence and incontinence. Take one popular treatment — radical prostatectomy, or complete removal of the prostate. That’s what Dr. Walsh performed on Sen. Kerry. He has pioneered a surgical technique that spares nearby nerves and drastically minimizes side effects. But not all surgeons are as proficient.

DR. PATRICK WALSH: Well, there was a study in the Journal of the American Medical Association published last year which said that 8 percent of men at various sites in the country that underwent surgery had major problems with urinary control, and only 40 percent of patients were potent. So there are major problems in the way this operation is performed.

SUSAN DENTZER: To help detect the presence of cancer, doctors employ two basic screening tests. The simplest is the digital rectal exam, in which a physician uses a finger to feel through the rectal wall for any abnormalities on the surface of the prostate.

The other widely used test is the PSA test, a blood test, costing about $30 to $50, that measures the level of a blood protein called prostate-specific antigen. The quantity of that protein is measured in nanograms, or billionths of a gram per milliliter of blood. Rising PSA levels can indicate the presence of infections, benign forms of prostate disease, or cancer.

DR. PATRICK WALSH: So for men in their forties, the PSA should not be higher than 2.5. For men in their fifties, it should not be higher than 3.5, and thereafter it should not be higher than 4.0.

SUSAN DENTZER: As with most screening tests, the PSA is far from perfect. In about one in five cases of men who are later shown to have prostate cancer, the PSA level actually appears normal, a so-called “false negative.”

By contrast, if the PSA is above four, it’s not enough to confer a diagnosis of cancer. Doctors must perform biopsies of tissue removed from the prostate to rule cancer in or out.

To fully answer the societal question — should broad populations of men get routine PSA screening, experts need evidence from large, randomized clinical trials. That’s when high numbers of men are randomly assigned by computer either to get or not get screening tests. They’re then followed for years to see who develops disease, how they respond to treatment and who dies.

The two groups are then compared to see what if any difference screening made. The National Cancer Institute has just such a trial underway now, but the results may not be known for five to ten years. Doctor Edward Gelmann is a top cancer specialist at Georgetown University Medical Center, one of the sites where the trial is underway.

DR. EDWARD GELMANN: If you screened everyone in the U.S. today, it would add a huge amount of money to both Medicare and insurance bills, and would result in at least 5,000 extra deaths from procedures that would result from the screening results.

So that although it will find cancers, and they will be cancers that will be treated, whether the total benefit of finding the cancers and treating them really is going to outweigh the complications, the worry, the expense, just has not been shown. And until we show it, recommending screening to the entire population is not justified.

SUSAN DENTZER: Besides the society-wide questions about screening, there’s also a debate about whether or not a given individual should be screened. On one side are groups like the American Cancer Society, which recommends annual PSA’s and digital rectal exams for men 50 and over, who have at least ten years of life expectancy ahead of them. That age threshold drops to 45 and over for high-risk men such as African-Americans, or for men with a strong family history of the disease.

DR. PATRICK WALSH: We know today, since screening has occurred, that today more men are diagnosed with curable disease. We know that the probability of a man walking into the office with cancer in his bones has fallen from 20 percent to 5 percent. And we know that the cancers that are picked up at a curable stage can be cured. So there are lots of reasons to believe that screening works.

SUSAN DENTZER: Not surprisingly, men whose prostate cancer was found partly through an elevated PSA also believe the tests are life-saving. Bob Russell is a top executive with a U.S. Government agency. His cancer was found after the agency sponsored free screening tests.

BOB RUSSELL: It’s the way of starting the process of seeing whether you are one of the ones that are perhaps unlucky, but you may have prostate cancer, and if you do something about it in a timely fashion, you can beat it. If you don’t, it’s going to beat you.

SUSAN DENTZER: On the other side of the debate are those who fear that screening can open up a Pandora’s box for patients. They say it can trigger a chain of events that may not result in patients living longer, or in having a high quality of life along the way.

DR. DAVID RANSOHOFF: There are a series of decisions that the patient and doctor are going to feel very compelled to make or to consider making, about biopsy, aggressive therapy, if anything labeled cancer is found.

SUSAN DENTZER: Doctor David Ransohoff is a medical school professor at the University of North Carolina at Chapel Hill. He’s written articles questioning the pervasiveness of prostate cancer screening. So far, he’s declined to be tested himself.

He explained why in this informational video for patients, produced by the Foundation for Informed Medical Decision Making, a joint effort of Dartmouth Medical School and Massachusetts General Hospital.

DR. DAVID RANSOHOFF: If I knew that by becoming impotent and incontinent I could beat cancer and prolong my life, if I knew that with a high degree of certainty, that would impact my decision. Because however we don’t know which cancers will kill you and that treatment makes a difference, we really don’t know, that trade-off becomes much more difficult and I’m less comfortable making it.

SUSAN DENTZER: So far, though, pro-screening forces seem to be winning the popular argument. At least 26 states have already passed laws mandating that health insurers include PSA tests in the policies they sell consumers. And analysts say the cancer diagnoses of Sen. Kerry and Pat Robertson are also likely to renew calls for widespread screening.