|DR. EDWARD GELMANN|
Dr. Edward Gelmann, a professor of oncology at Georgetown University School of Medicine is researching which men, if any, should be screened for prostate cancer using the prostate-specific antigen [PSA] test.
The NewsHour Health Unit is funded by a grant from The Henry J. Kaiser Family Foundation.
DENTZER: Let's talk about what you understand to be the weight of the
evidence right now, in favor or not in favor of PSA screening.
EDWARD GELMANN: Well, there is no question that if you perform PSA blood testing on men who have no symptoms and otherwise think they're fine, you will detect some men who have elevated PSA and of those men, some men will have prostate cancer. So that PSA does help detect prostate cancers that otherwise cannot be found.
But we have no information [about] whether finding those cancers is of any use at all. And I know that that's counterintuitive, but prostate cancer is a disease that happens in older men. Often those older men have other medical problems that threaten their lives much more acutely than does prostate cancer, and prostate cancer can be managed and controlled for a very long period of time; even if it's not cured, sometimes beyond 20 years, so that establishing a diagnosis and initiating a treatment may not really be in the benefit of the patient.
SUSAN DENTZER: Let's talk about the PLCO trial [Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial] at this point; specifically how is the trial set up and what is your role as the PI [Principal Investigator] here at Georgetown?
EDWARD GELMANN: Well, PLCO is being conducted at ten centers across the country, from Washington D.C. all the way to Honolulu. And we're one of those ten centers, and I've been running the trial operation here now for more than ten years.
The trial across the country is fully accrued, with 155,000 participants -- men and women, because we're screening for four different cancers -- who have volunteered to be randomized, assigned by a computer flip of the coin, to intensive screening for five years or just a phone call, "hello, how are you, how have you been?"
And in the long run, we will be following all of the participants, first of all, to identify cancer diagnoses when they occur and then to see what has happened to those people; has the cancer been caught in time, has it been effectively treated, has it come back? And as time goes on and some of the participants do die, to determine why they died, exactly what the cause of death was, to see the efficacy of the screening or not.
The trial was open to people who were 55 to 74 at the time they entered and will probably go on for 15 to 20 years before all the answers are in.
|Why testing may not be necessary|
SUSAN DENTZER: Let's go back to the whole question of the efficacy of PSA testing in particular. We did some calling around here to try to find patients who might be contemplating PSA screening. We talked to a number of internists in this community, and basically almost to a person they said, "What's the issue? We routinely recommend that our patients get screened."
The only question is how soon it starts or how late in life it starts, but no internist in the Washington D.C. area, we're told, would tell a man in his 40s not to get screened, in fact quite the opposite. So there is a sense that regular routine PSA screening for men, certainly men 40 and over, is the standard of care. Is that your experience and if it is or isn't, why is that the case?
EDWARD GELMANN: Well, I think 40 is definitely too young. Screening 40-year-old men without a substantial family history of prostate cancer is unlikely to give a very high yield and is likely to cost a lot of money. In my experience, physicians in the community will start screening at 50, and what that does is generates some diagnoses, generates a lot of worry and a lot of procedures, some of which are entirely unnecessary because we don't know if screening is beneficial.
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.
And in fact, right now there are three cancers for which screening tests have been shown to affect survival, and that is fecal occult blood testing for colon cancer, mammography for breast cancer in women over 50, and, of course, pap smears for cervix cancer.
SUSAN DENTZER: The people who are strong proponents of screening, in our experience many of them are people not unlike you. They're oncologists, they're people who work very closely with prostate cancer patients, or they're surgeons, and they say they have seen the havoc and the tragedy that prostate cancer can wreak in people's lives; that for every instance where a cancer is found that seems small and not likely to metastasize another patient walks in the door with cancer which very quickly metastasizes and results in the death of the patient.
So they say there's really no way to judge ahead of time which cancer is going to take which course, and therefore screening, because the test is available, is a slam dunk.
EDWARD GELMANN: You have to remember that if cancers are indeed predetermined to behave aggressively or not, then finding an aggressive cancer earlier than when it would have caused symptoms may not result in the person living one extra day.
You may find the cancer and you may go ahead and treat it, but you still may have metastases, and if that person was destined to die five years after the diagnoses, or four years after the cancer became symptomatic, that may not have been changed by the screening or the early treatment, and that phenomenon is called lead-time bias.
You find it earlier, and you think that you've helped someone because you've known about the cancer longer, but in fact, you haven't changed the day when it's going to cause mortality.
SUSAN DENTZER: So how would we ever find the answer to that?
EDWARD GELMANN: Well, the way you find the answer is you do a randomized trial that at the end of the day counts up the deaths due to a particular disease, because if screening works, then when you find the cancer early and remove it, you cure someone. And although we've all got to die of something, it's not going to be of that particular cancer.
SUSAN DENTZER: And so will that, in effect, be the answer that comes out of PLCO?
EDWARD GELMANN: That is certainly the expectation, and I think that answer will come out of PLCO, I just don't know if it will be a positive answer or not.
SUSAN DENTZER: Again, on the issue of the efficacy of screening, many people have told us that part of the reason that doctors are so inclined to do this is they get so many psychic benefits for doing it, from patients in effect. That if they recommend tests to patients, patients go out and get it.
If it's a negative test, patients are grateful to the doctor because it's negative. If they recommend that they get it and the patients find that it's positive, a cancer is found, they are biopsied, they are grateful to the doctor because they believe the cancer was found earlier, and they believe that they have a better prognosis because of that. So that, for a physician, there's every reason in the world to do this because the gratification that comes about from it is so immense.
EDWARD GELMANN: Well, first of all I understand that. Secondly, a lot of medicine in this country is both demand-driven and procedure-rewarded. As an oncologist, I'm paid to do procedures and give chemotherapy much more readily than I'm paid to spend time with my patients. So that, as long as medicine in this society is rewarded by procedures and by getting results and doing lab tests, I think demand is going to continue to drive that until we have data. But right now we don't have data, and when we do have data, it may change the screening practices.
I'll remind you that everyone believed in hormone-replacement therapy for women until a very large, very long-term study recently showed us that, in fact, there were potentially greater risks and harms than benefits from that therapy.
|The interim results of ongoing studies|
SUSAN DENTZER: I want to talk about the Scandinavian trials, the results of which were published in September in the New England Journal of Medicine because the proponents of screening, who often tend to also be proponents of aggressive therapies, prostatectomy in particular, say that that study indicated very clearly that prostatectomy is superior to watchful waiting in terms of increasing survival, and therefore, that that is in effect for many men going to be and should be the treatment of choice.
I know there's controversy over what that study actually showed, what is your sense of what that study indicated?
EDWARD GELMANN: Well, first of all that study was a good study, a randomized study that is providing important and valid data. The study is still ongoing. The reports that were published in the New England Journal of Medicine were interim reports that had something to say about the chance of having recurrent prostate cancer a certain number of years after having an operation, but didn't say anything about overall survival. So there were in fact, in the paper, in the New England Journal, there were not survival differences in the two groups. There were differences in the recurrence rate of prostate cancer, but that doesn't necessarily mean that over time, those differences will even out.
So although it's a very provocative piece of information, the final chapter on that study has not yet been recorded.
SUSAN DENTZER: In the final analysis, what do you think these interim results actually show or don't show?
EDWARD GELMANN: Well, they show that for the five to seven year time span after surgery, that compared to the group that didn't have surgery, you're less likely to have a prostate cancer recurrence, but that doesn't mean in the future you won't have a prostate cancer recurrence. It just means that in this relatively short time span, you don't.
Men with prostate cancer that's diagnosed early, whether they have surgery, radiation, or observation, overwhelmingly live a long time. We can manage this disease very well, and so that the studies involving treatment or observation of prostate cancer are going to have to last well over a decade for us to figure out what treatments are worthwhile.
|The public's perception of prostate cancer|
SUSAN DENTZER: So the picture that many people have, which to put it succinctly, is probably something like this: "Prostate cancer is a terrible disease. I have to get screened for it. If I don't get screened for it, I might have it. It might kill me soon." Your saying that's not a reasonable picture?
EDWARD GELMANN: In the vast majority of cases, prostate cancer, even if it is beyond the scope of local treatment, can be managed for a very long time, and patients can live entirely normal lives for many years with their prostate cancer, which is one of the big issues about this disease, that we have very effective ways of managing it.
SUSAN DENTZER: And some men have also, or some doctors have asserted to us that there's a psychic cost to patients as being sort of labeled a cancer patient. Even if you elect to have watchful waiting, all of a sudden you are self-defined as somebody who has cancer?
EDWARD GELMANN: That's certainly true. Twenty years ago when it was not fashionable to have cancer, that was a much greater issue. Now that you've got senators and generals and whatever parading on television and announcing how they beat it, I think there is a certain -- it's come out of the closet, and I think that's a good thing.
I think we need to recognize that we're all human, that we can all get sick, and we can all overcome certain obstacles. And it's been very heartening actually, to see public figures take the approach that they could share their experiences and that's helped a lot of other people go through experiences like that. So I think that's less of an issue today.