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Prostate Cancer Screening: The Pros and Cons

The views expressed are those of the author and are not necessarily those of Scientific American.

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The U.S. Preventive Services Task Force is about to recommend that healthy men forgo being screened for prostate cancer with the familiar PSA (prostate-specific antigen) blood test. They base the recommendation on several respected human trials indicating that the screening does not save lives. The announcement is sure to roil an already bubbling controversy over the value of that screening. For context, here is a summary of the arguments that doctors on both side of the question often put forward.

Arguments in favor of PSA screening:

–Catching cancer early, when it is still curable, is important.

–Early detection and treatment can prevent deadly metastatic disease. If you don’t find the cancer early, you can miss out on the chance of a cure.

–Patients will be able to tolerate the effects of treatment much better if they are treated at a younger age.

–The overall incidence of deaths from prostate cancer has decreased over the past 20 years; this decline must stem from widespread introduction of PSA testing and treatment.

–We are lucky to have a blood test that, in the absence of any overt physical indicators, can help reveal that a cancer may be present.

–The studies that have been performed on the value of PSA screening need additional longer-term follow-pup; negative results could be the result of evaluating the data prematurely.

–To continue to see death from prostate cancer decline further, even more vigorous screening programs need to be put in place.

–A new trend in caring for men with prostate cancer found by the PSA test is “active surveillance,” in which men are not treated immediately but are closely monitored with various follow-up tests; treatment begins when signs indicate the cancer is becoming dangerous and needs treatment. But that practice is akin to playing Russian roulette, because test results can underestimate the stage, or extent of progression, of the cancer.

Arguments against PSA Screening:

–Long-term studies that have followed men for more than 20 years shows no difference in death rates between those screened and those not screened.

–If a PSA level is suspicious, men then need to have a biopsy of the gland; if cancer is found, they need to consider treatment. The weight of the evidence argues that men who go that route do not have a lower death rate from prostate cancer than people who were never screened.

–The average age of prostate cancer diagnosis is 71 to 73; men in that age group are more likely to die of other diseases

–The side effects of treatment can include urinary incontinence, erectile dysfunction, and, in those who opt for radiation, inflammation of the lower rectum or bladder. These side effects cause important alterations in patients’ quality of life and are hard to justify given that many patients diagnosed with prostate cancer as a result of the PSA test would never suffered any symptoms from their cancer. And those are not the only risks: Many side effects such as fecal incontinence are underreported.

–There is no credible evidence that low-grade prostate cancer uniformly progresses to higher grade cancers, so early treatment is not necessarily needed.

–Active surveillance can help to avoid excessive treatment in response to a PSA test, while ensuring that men who need treatment get it in time to save their lives. When men have been part of active surveillance programs, the likelihood of their dying of non-prostate cancer related reasons was 14 times greater than dying of prostate cancer, so active surveillance seems like a reasonable way of minimizing the negative consequences of PSA testing. Active surveillance is under continuing study.

I should note that men who have a strong family history of prostate cancer and who are African American have a higher likelihood of getting prostate cancer, so those people will probably continue to get tested. I also think it will be important to continue to do PSA testing in men with enlarged prostates who are treated with drugs known as 5-alpha-reductase inhibitors (Proscar/Finasteride or Avodart/dutasteride), since PSA levels should decrease in response to treatment; if the PSA does not decline, these men may be at higher risk of developing the disease.

In the end, we urgently need a screening test that can distinguish well between prostate cancers that will become life-threatening and those that will not, and we need treatments that come with fewer risks of severe side effects.

Editor’s note (10/8/11): The first two sentences of the penultimate paragraph were changed for clarification.

About the Author: Marc B Garnick is a prostate cancer expert at Harvard's Medical School and Beth Israel Deaconess Medical Center and editor-in-chief of the Harvard Medical School's Annual Report on Prostate Diseases

The views expressed are those of the author and are not necessarily those of Scientific American.

Comments 8 Comments

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  1. 1. bigbopper 3:04 pm 10/7/2011

    The basic problem which bedevils any discussion on this topic is the difference between an outcome in a specific individual versus in groups of patients. In any one individual screening for prostate cancer could be a lifesaver. But when one considers large groups of men, one can’t see any statistically significant difference in longterm outcomes between those who are screened versus those who aren’t.

    This is the same type of problem encountered in many other similar types of topics, e.g. the recent controversy on the FDA rescinding its approval of Avastin for metastatic breast cancer, or the USPSTF’s previous change in its recommendations regarding screening mammograms.

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  2. 2. Postulator 6:18 pm 10/7/2011

    You may want to edit the article slightly. It implies that men who are African American are unhealthy. In fact, the first couple of sentences in that paragraph need a complete rewrite.

    Having heard all about the side effects of the surgery performed in removing what is most commonly benign prostate growths, I think if I were in the position of having been randomly screened and found to have a problem I’d opt against any action.

    Of course, there remains a need for review where patients have specific symptoms that point to a prostate problem.

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  3. 3. jeffreydav 9:16 am 10/10/2011

    Another example of bureaucracy run a muck! The consequences are far reaching, not the least of which is the needless death of countless men. Had I not been screened I would never have had the opportunity to post this … I would have died of prostate cancer before reaching age 60!

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  4. 4. jgrosay 11:41 am 10/10/2011

    Dear Marc: thank you for this interesting warning on PSA prostate cancer screening. Are you aware about any official or academic oppinion on the 2011 ASCO Annual Meeting’s abstract Nº 4512 , by H Lilja et al, NY, that is a proposal for a new prostate cancer screening strategy, reducing number of PSA tests to 3 in lifetime for 40% or more of men, thus a cheaper PSA prostate cancer screening approach ?. Also, as far as I know, no officially endorsed explanation exists for the fact that prostate cancer specific mortality started to decrease in coincidence with the introduction in the market of the PSA test. Salut +

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  6. 6. johnson 9:02 am 02/23/2012

    jgrosay: look further: it also declined in countries where they do NOT do screening, some places even more than in the US.

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  7. 7. adam.davies 9:18 am 04/11/2012

    I have found that avoiding screening doesn’t really make any sense. Avoidance is usually the result of embarrassment and in the long term that can’t really justify not getting screened.

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  8. 8. tyrimai 8:46 am 04/5/2013

    I think the main advantages are:
    * ir reassure you, if it is normal;
    * you find cancers before any symptoms develop.

    Sincerely, kraujo tyrimai

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