• Prostate cancer screening: What’s all the fuss about?

    I’ve posted many times on prostate cancer screening and treatment, and I will be writing more about it. Likely some readers don’t know why there is such a fuss about prostate cancer. A good answer is provided by Boyle and Brawley in a 2009 article that appeared in CA Cancer J Clin:

    [A]n average man who gets screened is 48 times more likely to be harmed by screening than he is to be saved by screening at 9 years after diagnosis. The harms include that he may be diagnosed, undergo needless treatment, and suffer the side effects of prostate cancer treatment, which can include impotence, incontinence, mental anguish, and even death.

    Let that sink in. These are not insignificant risks, nor are they rare. Impotence rates are near 50% for some treatment modalities. Incontinence is also quite common. Even if they can be addressed with pharmaceuticals, that’s not by itself a justification for risking their occurrence unless it significantly decreases the chances of an even worse outcome. Does it?

    The real impact and tragedy of prostate cancer screening is the doubling of the lifetime risk of a diagnosis of prostate cancer with little if any decrease in the risk of dying from this disease. In 1985, before PSA screening was available, an American man had an 8.7% lifetime risk of being diagnosed with prostate cancer and a 2.5% lifetime risk of dying from the disease. Twenty years later, in 2005, an American man had a 17% lifetime risk of being diagnosed with prostate cancer and a 3% risk of dying from prostate cancer.

    In the best case scenario, […] a 20% reduction in the risk of death means the average man who chooses screening decreases his risk of prostate cancer death from a lifetime risk of 3% to a lifetime risk of 2.4%. In exchange, he increases his risk of diagnosis from between 6% and 9% to at least 17%. In a heavily screened population, the risk of diagnosis is likely more than doubled to >20%.

    Is more than doubling one’s risk of diagnosis worth the absolute decrease in prostate cancer death risk from 3% to 2.4%, if indeed there is this 20% decrease in risk?

    There’s no right answer. However, when you add the costs of screening and treatment into the mix (which can be as high as tens of thousands of dollars per treated patient), and the fact that much of those costs are paid by taxpayers, it puts a premium on thinking about this issue very carefully, not just personally, but programmatically.

    Addendum: Anybody care to estimate how much is spent in the U.S. on prostate cancer screening? I’ve got a citation with values from the late 1980s for the direct screening costs and the total downstream costs of all resulting, related care. I’ll share if there is interest. But I’m also curious to see if anyone’s got a more recent figure. (It’s a simple matter to update the late 1980s figures for inflation, but that won’t account for changes in practice patterns and technology.)

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    • People seem to have blocked out the non-monetary downsides to over treatment.

      There is also always a risk of accident in any surgery. I guy who worked for my father died for complications in surgery to graft hair on to head because he did not like being bald! I think about that when I think of all those tonsillectomies that were done back in the 1960’s.

    • What you say is true for PSA screening, but the data on Provenge is different, since it is approved only for very advanced prostate cancer and shows clear clinical benefits for that population.

      Unknown: How often it will be prescribed off label, which affects cost-effectiveness evaluations.