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Wed August 14, 2013
New Drug Study Revives Debate Over Prostate Cancer Screening
Originally published on Fri August 16, 2013 3:40 am
ROBERT SIEGEL, HOST:
It's clear from Dick Knox's story just now that there are a lot of caveats that come along with the study of finasteride. One physician, Dr. Michael LeFevre, certainly feels that way. Dr. LeFevre is a professor at University of Missouri Medical School, and he's co-vice chair of the United States Preventive Services Task Force. He joins us now from Columbia, Missouri. Welcome.
DR. MICHAEL LEFEVRE: Thanks very much.
SIEGEL: I take it you do not see this new drug finasteride as a game changer in the fight against prostate cancer. Is that right?
LEFEVRE: Well, I don't think that this is a major turning point in the debate about the balance, the benefits and harms of prostate cancer screening. But I do think it's a very important study.
SIEGEL: But the argument against widespread PSA screening is that a high percentage of men treated - as a result of screenings and positive results - would never have really been liable to get cancer and they're treated nonetheless. Is that correct?
LEFEVRE: Absolutely true.
SIEGEL: And would finasteride in any way figure in those cases and alter the treatments men would receive?
LEFEVRE: I think this has the potential to change the equation somewhat. When the task force looked at this issue, the task force did not feel that the potential benefit from prostate cancer screening, which was probably at most one death avoided per 1,000 men screened, outweighed the harms associated with principally finding and treating more cancers than we need to. So I do think that for men who choose to be screened, this is a new and important consideration.
SIEGEL: Of course, when a doctor like yourself says that - only one in 1,000 - there are a lot of men out there saying: Yeah, but if I'm that one in 1,000, I say go for it.
LEFEVRE: Yeah, we always hear that story, of course, from the positive side of things. But you can do the flip, which is if we're looking at avoiding the harms of screening, let's just hone right in on death. Prostatectomy is the most common treatment for prostate cancer in the United States today. Certainly, one estimate puts about 1 in 250 men dying from complications of the surgery. And unfortunately, that's surgery that didn't need to happen for a significant number of men.
SIEGEL: And short of death, other harms of treating prostate cancer?
LEFEVRE: Absolutely. Of those thousand men screened, we're looking at about 30 to 40 men who would develop sexual dysfunction or erectile dysfunction or urinary incontinence - loss of control over your urine - or both. A couple of men will have a serious event such as a heart attack or a stroke. At least one man will have a serious blood clot in his legs or lungs due to the treatment. And as I already said, about one in 3,000 men will actually die.
But if we can, as we are now seeing with the finasteride trial, reduce the number of men who are treated unnecessarily, then very clearly, we're doing less harm in shifting that balance somewhat.
SIEGEL: Now what about, as you understand them, the harms of finasteride as opposed to the benefits?
LEFEVRE: Well, I think that men who choose to take finasteride should certainly still be aware that we have some uncertainty about what the effect is on the diagnosis of advance cancer. Whatever effect it has on the diagnosis, either low-grade or aggressive cancers, it doesn't change how long you're going to live.
SIEGEL: So as a physician, would you see a point to prescribing finasteride, or would there be a very, very long informed consent conversation before you did?
LEFEVRE: I think that a man might make a very reasonable decision after they've already decided that they want to be screened with PSA. Then I think they could make a reasonable decision to try to minimize the harms of that screening by taking finasteride to lower the chance that they're going to be diagnosed with the cancer and suffer from the treatment of that cancer and, in many circumstances, a cancer that would not have hurt them.
SIEGEL: And what do you make of this seemingly odd phenomenon of people who do then have prostate cancer getting a more lethal form of it if they've taken finasteride?
LEFEVRE: There have been many people who have challenged that finding and said: Well, this is really because of the way we looked for cancers or some of the other, we would call biases associated with the study. You would expect that if, in fact, finasteride causes a significant increase in high-grade cancers, that over time, we would see that those men, in fact, would have shorter lives.
And we did not see that. And so, I think that it's certainly a reassuring study in terms of the safety of finasteride.
SIEGEL: Dr. Michael LeFevre, thank you very much.
LEFEVRE: Absolutely. Thanks for having me.
SIEGEL: Dr. LeFevre is a professor of F0amily and Community Medicine at the University of Missouri.
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