Cancer Screening

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For decades, we’ve been told that cancer screening saves lives through early detection and subsequent treatment of the disease. Now, an article published in the Journal of the American Medical Association suggests that screening for breast and prostate cancer may not be as beneficial as once thought. Dr. Peter Lance, Director of Cancer Prevention and Control for the University of Arizona’s Arizona Cancer Center shares his views on cancer screening.

Richard Ruelas: For decades, we've been told cancer screening saves lives through early detection and subsequent treatment of the disease. Now an article published in the journal of the American Medical Association suggests that screening for breast and prostate cancer may not be as effective as once thought. Here now to talk about that is Dr. Peter Lance, director of cancer prevention and control for the University of Arizona's Arizona cancer center. Two Arizonas in the name. Thanks for joining us.

Peter Lance, MD: My pleasure.

Richard Ruelas: Well, where to begin? The American cancer society quoted in the "New York Times" saying we don't want people to panic, but admitting American medicine has overpromised when it comes to screening. The advantages to screening have been exaggerated. This is a major sea change in the thought about cancer. How do you see it?

Peter Lance, MD: I guess that's one way of looking at it. I would say this is all fairly north topic, and it's one that where we make incremental progress. And so whereas one would like to come out with a bit of boilerplate which says everybody should do X, Y, Z, and cancer will go away, unfortunately that isn't how things work in the real world. So we continue to gather data as we go along, and an underlying premise as you outlined in your lead-in piece, is that if you diagnose a cancer at an early stage and that means by early we mean how far into the tissues it's spread at the time it's diagnosed, in general the earlier the better. And -- because the general assumption that if you diagnose a cancer earlier rather than later, it will be more easily treated and done away with and thrown in the bucket and we go on with our lives. One of the problems with screening, though, is that we understand that just because we increase the number of cancers that we diagnose at an early stage, that doesn't necessarily mean that we automatically increase the number of those cancers that are most aggressive and are actually going to threaten our lives by increasing the general number that we diagnose at an early stage. So this is -- these are issues that have arisen over the years, but have come to the floor recently, particularly with respect to prostate cancer and breast cancer.

Richard Ruelas: It is counterintuitive, but I guess this is part of the push to screen. We hear so many success stories of people who have had the screening, they've caught it early, it's tossed in the bucket and they move on with their lives. Have those caused a false sense of security?

Peter Lance, MD: You know, I think the important thing from the general public's point of view is that we shouldn't make an extreme U-turn, that we should actually be measured and take the new information as it comes along. I think one important concept to get out there for the public is that not all cancers are equal. So some cancers start out on very quickly, they're like a wildfire. They catch fire and they spread. And maybe people can understand that if you have a cancer that is developing more slowly, gentler, over a period of years, then if you can diagnose, you're more likely to pick up that cancer by screening. By picking up preferentially those cancers that maybe have a less aggressive what we would call natural history, we may somewhat delude ourselves into thinking that we're automatically having a commensurately beneficial effect on the overall cancer burden. And so I think what is arising -- what people are noticing is that, yes, indeed, we're diagnosing more and more breast cancers and colon cancers at a, quote, early stage, but that isn't having the desired impact on the number of cancers that are still being diagnosed at what we might call a regional or cancers that may have spread to the rest of the body.

Richard Ruelas: Meaning I guess like a success rate, the number of those cancers you can toss in the bucket.

Peter Lance, MD: So one of the things that may be happening is that we are tossing more cancers in the bucket, but we're not actually preferentially getting all of those cancers that in fact are behaving aggressively. So, for instance, if you look at prostate cancer, it's been known for a long time from autopsy studies that if you do autopsies on men dying from completely unrelated causes in their 80s and 90s, many of them will have little prostate cancers at the time that they died from another -- from their stroke, heart attack, or whatever. And clearly those prostate cancers that you can diagnose in elderly men of an autopsy weren't threatening their lives. They died of something unrelated. Nowadays lots of people get to 100, and that's what we're all aiming for. The problem is it may be that screening is picking up more of those cancers that could otherwise crop up in men who are dying from unrelated causes later on.

Richard Ruelas: Does that cause, say, unnecessary surgeries, or unnecessary removals of prostates?

Peter Lance, MD: That does actually mean that some men probably are getting unnecessarily aggressive surgery for prostate cancer, because we're identifying those early cancers that are relatively indolent and are probably not going on to cause cancer.

Richard Ruelas: Once you get the result that says you have cancer in your body, the patient's tendency is not to do what I guess is called watchful waiting, let's just carve it out and try to treat it.

Peter Lance, MD: I think it's -- I think the American cancer society has been very fair over the years in the way that it makes recommendations, and to be fair to the American Cancer Society, if you look at their official screening recommendations for prostate cancer, for instance, they make it clear that they don't think that even if all men get a PSA test that's a blood test for prostate cancer from the age of 50 on, that is not going to get rid of the problem of prostate cancer. And they've been very careful to say for a number of years now that the evidence that this is going to eradicate prostate cancer just isn't there yet, and also to say that we have to be careful that men don't have unnecessary surgery or surgery that is overly aggressive.

Richard Ruelas: Would you recommend continued screening, that the public continue to get regular breast -- self-exams, say, or prostate checks?

Peter Lance, MD: Then, you know, this is when the doctor becomes the lawyer, and I kind of punt on that one. But I think the American cancer society has made entirely the right recommendation that they say this is something that the individual patient should discuss with -- in the case of prostate cancer, his physician or in the case of a woman, her physician with regard to breast cancer. So I think it needs to be done on an individual basis, and for instance, other factors, is there a family history, we know, for instance, that also prostate cancer occurs at a younger age and is more aggressive in African-Americans. So there are other features that one needs to bring into the mix here, but it has to be -- the recommendation should be individualized.

Richard Ruelas: I guess as the medical commercials say, ask your doctor if prostate cancer and breast screening is right for you.

Peter Lance, MD: Yes.

Richard Ruelas: Thank you for joining us this evening.

Peter Lance, MD:My pleasure.

Dr. Peter Lance:Director of Cancer Prevention and Control for the University of Arizona's Arizona Cancer Center;

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