Prostate Cancer Testing

Read the Full Transcript

• GWEN IFILL:

  Millions of men will undergo one of two tests to determine whether they have prostate cancer this year. These tests, including the PSA, or Prostate-Specific Antigen test, are now routinely given to men over the age of 50. But how effective are they? A government task force has been studying that question, and has come up with a mixed answer. Joining me now is the chairman of that task force, Dr. Alfred Berg. He also heads the Department of Family Medicine at the University of Washington. So, Dr. Berg, what are we to make of these test results? Is a PSA test taken after the age of 50 an effective predictor of cancer death?

• DR. ALFRED BERG:

  Well, our group found the evidence was insufficient to recommend for or against routine prostate cancer screening, and the reason is that we have inconclusive evidence that screening and early treatment improves health outcomes. So we were unable to determine whether the balance of benefits and harms favored benefits or the harms.

• GWEN IFILL:

  In 1996, your group, as I understand it, also just flat out said that these screenings aren't really worth it. So this has been a move back toward the middle kind of, hasn't it?

• DR. ALFRED BERG:

  Well, I wouldn't overstate the change. There are two things that have happened. First of all, of course, in the last six years there's been more scientific evidence; but secondly, the methods that we've used to do these reviews and the criteria that we use to reach our conclusions have changed. So that we now consider, for example, not only the quality of evidence but the balance of benefits and harms. So we have new evidence, new methods and new criteria and now a new recommendation.

• GWEN IFILL:

  You talk about the balance of benefits and harms. What is the argument against just getting the screening anyway? Is there a problem of getting the screening or is there a problem with what you do with the information you get?

• DR. ALFRED BERG:

  Well, all screening programs have some potential down side. In the case of screening for prostate cancer, if you have a positive screen, you usually need to go under some sort of evaluation to determine whether prostate cancer is there or not — usually prostate cancer biopsy. If the biopsy is positive, then treatment using either surgery or radiation are the most common. All of those things can cause adverse events either associated with the procedures themselves or later on complications.

• GWEN IFILL:

  How big is the problem? Right now, give us a sense of how big a killer, I guess, prostate cancer is now in the general population?

• DR. ALFRED BERG:

  Well, prostate cancer is an extremely important problem among men in this country. Probably 3 percent of men will die of prostate cancer — about 189,000 new cases a year, and about 30,000 deaths. It's the second leading cause of cancer-related deaths right behind lung cancer for American men.

• GWEN IFILL:

  And if you have this PSA blood test and it shows that you have or there is an indication that there may be cancer cells in this test, is it always a definite sign that there is cancer or are there false positives sometimes involved in this test?

• DR. ALFRED BERG:

  Well, you're exactly right. Actually most of the positive screening tests are false positives. Anywhere from 80 to 75 percent of the initial screening tests prove to be false positives on subsequent evaluation.

• GWEN IFILL:

  If 75 percent of the tests are false positives, and you're one of that 75 percent and your doctor still recommends surgery, are you just over treating 75 percent of the people who take this test?

• DR. ALFRED BERG:

  Well, it's important to draw a distinction between the evaluation for prostate cancer and the treatment for prostate cancer. When I talk about false positives, that's the number of tests that are positive initially that prove not to be prostate cancer. So those individuals who have a positive screening test but then prove not to have cancer obviously would not be treated.

• GWEN IFILL:

  So if you do get a treatment, if you do get surgery, what's the potential down side? What are the side effects?

• DR. ALFRED BERG:

  Well, surgery or radiation

• GWEN IFILL:

  Or radiation.

• DR. ALFRED BERG:

  …They have effects immediately. It's of course extremely rare but people do die from surgery. But more commonly side effects can happen years later. There can be incontinence of urine, inability to control the bladder, impotence, erectile dysfunction, bowel problems.

• GWEN IFILL:

  So the trade-off isn't necessarily a good one.

• DR. ALFRED BERG:

  No. It's a very difficult decision because you're trading off potential benefits that are unproven but huge, the possibility of being saved from dying from prostate cancer against potential harms which are also significant.

• GWEN IFILL:

  What are we as laymen and lay women to make of these kinds of findings? Periodically we hear the same types of reports from mammograms, pap smears and now about prostate cancer affecting men. What are average people who are worried about their health and they're concerned about the potential for contracting a deadly disease, what are they to make of this information?

• DR. ALFRED BERG:

  I think the important message is that patients need to take control of this decision. They need to get information from their clinicians about the potential benefits, about the potential harms, but then they need to take into account their own personal circumstances, their own personal risk, their personal values and preferences before they make a decision whether or not to be screened.

• GWEN IFILL:

  Is that decision influenced by how old you are? Would you make a different decision if you're 50 than if you're 80?

• DR. ALFRED BERG:

  Well, absolutely. Prostate cancer, of course, is much more common as men age. If you live to be 100, you probably have a 100 percent chance of having cancer cells in your prostate gland. On the other hand, the older you are and the more other medical problems that you have, the less likely prostate cancer screening would be of benefit. So it's a trade-off between increasing age with increasing risk but also increasing likelihood that something else will be the major health problem, not the prostate cancer.

• GWEN IFILL:

  Let me throw another problem into this mix. Another report released by a different group on Monday says that black men have a higher rate, a bigger chance… a greater chance of getting the deadlier, faster-moving cancers and therefore would benefit more from this increased prostrate screening. Isn't that a different message than the one you're sending today?

• DR. ALFRED BERG:

  Well, first of all I think it's important to point out that even among African-American men we don't have evidence that screening improves health outcomes. So if we did that have evidence it would make sense that African-American men should be screened. Right now though what we're recommending is that everyone should assess their risk. African-American men are at higher risk. On the other hand, Asian-American and Hispanic men are at lower risk. So it's a combination of risk, age, personal preferences and values.

• GWEN IFILL:

  When we talk about the accuracy of these tests, is there some way to make them more accurate? Is this an ongoing project or is this something we just have to understand it's going to be an unsure outcome?

• DR. ALFRED BERG:

  There's a great deal of research going on trying to answer exactly that question because what we really like to know is when we detect a cancer at screening, is it a cancer that would be best left alone or is it a cancer that really needs to be treated? So there's a great deal of research going on right now to try to answer that question.

• GWEN IFILL:

  Is there any discussion also going on about how you convince someone if they have cancer that it shouldn't be treated. How do you tell someone they have cancer which they are led to believe is a deadly disease that they should just watch and wait?

• DR. ALFRED BERG:

  Well, I think that the first choice should be whether or not you have the screening test done. You really shouldn't have the screening test done unless you're willing to the evaluation and the potential treatment. So the choice really should be made before you get to that difficult decision.

• GWEN IFILL:

  So the choice, just to be clear, should be made before you get the test or after you get the result of the test and before you opt for treatment?

• DR. ALFRED BERG:

  Our recommendation is that you ought to consider the potential benefits and harms before you have the test and make the decision on that basis and not wait until you have a positive test in order to decide whether you want further evaluation and treatment.

• GWEN IFILL:

  Dr. Alfred Berg, thank you very much for joining us.

• DR. ALFRED BERG:

  You're quite welcome.