Posted by: ateedub | February 2, 2009

Dealing With Uncertainty

Before my blogging sabbatical, I was working on an article about the “new” prostate cancer screening recommendation recently released by the US Preventive Services Task Force.

Until this report came out in August, the standing recommendation was generally understood to be that men over the age of 50 should be screened via PSA testing and a DRE. The 2008 USPSTF report found that they couldn’t determine whether there was any benefit to screening over the age of 75. So the new recommendation is not against testing men over 75, because the harms are likely to outweigh the benefits.

When you look closely, there’s no change in recommendations. I’ve spoken with three leading specialists in prostate cancer treatment and research from three different practice fields. They all agree that for all intents and purposes, this does not change how a doctor should care for a 75-year old man.

Interestingly, the urologist with whom I spoke (who is a member of a surgical society that does not accept the new recommendations), said that nothing changed and it won’t affect his practice. The medical oncologist was somewhat concerned about the overall message about screening being less clear – because she treats patients whose cancer was not found early enough. And the population scientist felt very strongly that these findings were important because the data do not support any benefit coming from screening.

To illustrate how these three opinions about the report could boil down to the same conclusion of no change in the way care is provided, you have to look closely at the language. The American Cancer Society‘s recommendation says that men should have a conversation about PSA testing with their doctors starting at age 50:

The American Cancer Society (ACS) does not support routine testing for prostate cancer at this time. ACS does believe that health care professionals should discuss the potential benefits and limitations of prostate cancer early detection testing with men before any testing begins. This discussion should include an offer for testing with the prostate-specific antigen (PSA) blood test and digital rectal exam (DRE) yearly, beginning at age 50, to men who are at average risk of prostate cancer and have at least a 10-year life expectancy.

The language is pretty vague, but essentially the recommendation is to have a discussion; whether you’re over 50 or over 75.  And this makes sense to me. There are many factors that go into this decision, and it illustrates the “art” that goes into medicine. We don’t have a one-size-fits-all approach.

But I think the way we deal with uncertainty as individuals makes us want medicine to be a science. The urologist I spoke with is comfortable because he doesn’t perceive any uncertainty in the decision. If an active 80-year old comes into his office for screening, he will have the discussion with him. If a 55-year old in poorer health comes in, he’ll also have the discussion.

On the other hand the population scientist was adamant that the data show no benefit, much like Schweitzer. In fact, she is waiting for the results of the PLCO (prostate, lung, colorectal, and ovarian) Cancer Screening Trial, because as the ACS statement alludes to, the benefit of PSA testing is not clear.  Perhaps the population-wide study will not find that lives are being saved – or at least extended – through early detection. Or perhaps it will find that they are, but that the negative impacts of screening (false positives, false negatives, excess biopsies, etc.) make the relative benefit very small. She’s unprepared to deal with the uncertainty.

The medical oncologist wants everyone to be screened. She doesn’t care about the uncertainty, as long as at least one person benefits.

I did not end up writing the story about this for work because I ran out of time trying to find a coherent narrative about it for my institution. It’s a little hard to weave these difficult conversations about uncertainty into an official story.


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