Stupidity, Irresponsible Stupidity, and Statistics

I am ending my recent blog silence because I feel compelled to write in support of Newt Gingrich.

Now I can’t say I support the way that Newt has chosen to conduct his personal life. And sure, his combative political style arguably played a big role in bringing us to sorry state of politics that we find ourselves in today. But buried inside of all that combative style (and all that white hair) is Newt’s stance on issues.

Actually, I don’t agree with Mr. Gingrich on some of those issues. For example, international issues. And domestic social issues. And economic issues. Really most issues.

But one issue Newt and I agree about completely is that the United States Preventative Services Task Force (USPSTF) got it wrong when it recommended ending routine Prostate Specific Antigen (PSA) testing. Newt and I both think that was a boneheaded move. It is likely to lead to the deaths of a small but significant number of relatively young men with aggressive prostate cancers. In other words, men like me.

A quick description of the test: “Prostate Specific Antigen” (PSA) is a chemical produced by the prostate in men. Some PSA always leaks from the prostate into the bloodstream. If there are problems with the prostate then blood levels of PSA can increase. So the PSA test is just a blood test.

The PSA test is like a very nonspecific warning light on the dash of your car. When it comes on you don’t know if you’re low on wiper fluid or about to lose your last drop of engine oil. All it tells you is you should pull over and take a closer look.

An elevated PSA doesn’t tell a man he has cancer. In most cases he doesn’t. And if a man gets a biopsy and learns he has cancer, in most cases that cancer is not very aggressive. In many cases an older man can just keep an eye on it, because he’s going to die of something else before the prostate cancer has time to kill him anyway. But some prostate cancer is aggressive, and some of it occurs in men who are not very old. In other words, men like me.

By the time a man in his 40s or 50s has symptoms from an aggressive prostate cancer, it has probably already spread. While it’s still in the prostate that cancer is unlikely to cause any symptoms and it probably won’t even show up on a digital exam. An elevated level of PSA is probably the only indicator there is a problem. So if we discontinue the PSA then men are going to die when they could have been saved. Men like me.

The argument of the United States Preventative Services Task Force goes like this: Most elevated PSAs don’t turn out to be cancer. Elevated PSA results can lead to biopsies and biopsies can sometimes cause infections. If the biopsy is positive, too many men choose to treat their cancer more aggressively than necessary, risking the side effects of urinary incontinence and impotence. So better just not to do the blood test in the first place. That will eliminate the risk of people doing the wrong thing with that information.

As a psychology graduate student I learned a lot about statistics (I would venture to say I am in the 99th percentile of statistical analysis skills), but all the reasoning needed to see through the task force’s bad decision is learned in a typical lecture everyone hears at least once during their first year of college. At the beginning of a lecture, the professor will point out (for example) that statistics show crime is highest in areas with the highest concentration of churches. At this point, the members of the Preventative Services Task Force apparently stood up and left the lecture, so eager were they to issue a statement that churches should be banned immediately. The point of the lecture, of course, turns out to be that correlation does not equal causation. Although churches and crime are correlated, they are most likely unrelated to each other but instead are both correlated with population. The deeper lesson is that a superficial view of statistics can lead to stupid conclusions if one attempts to consider statistics out of the context of everything else that is known. An educated person hears of a correlation like that and says “that doesn’t seem right — what else might be going on here?”.

In this case, I wish the Task Force had paused and thought, “Letting cancer grow without even checking to see if it’s the dangerous kind? That doesn’t seem right. What recommendations could we make that would reduce over-treatment but still let men make informed decisions so that those with aggressive cancer can live?”. Unfortunately they charged stubbornly ahead. They ignored entire disciplines of knowledge, didn’t include a single expert on prostate cancer, and made a stupid recommendation that will cause some men to die. Men like me.

My advice:

  • Get tested. The usual recommendation is to wait until age 50. Since I was diagnosed at 43 and have no family history I’m aware of, I think you should do it sooner.
  • If your PSA is elevated, don’t freak out. I kinda did freak out and it turned out to be with good reason. But for most people it’s probably not cancer.
  • If you get a biopsy and it shows cancer, don’t freak out. If it’s just a little bit of Gleason 6 cancer (the most common kind) you’ll probably die of something else even if you do nothing to treat the cancer. But talk to somebody knowledgeable — somebody without a stake in your decision — to help you decide.

I can never forgive the United States Preventative Services Task Force for what they’ve done. Too many men already avoid this simple screening. Even if the USPSTF changes their recommendation now, too many men will not get that message and will use this controversy as a reason to skip the test. Some of those men will likely die when they could have been saved.

I also have a lot of trouble forgiving the USPSTF position that since men like me don’t show up strongly enough in their aggregate statistics, we don’t matter and can simply be allowed to die. It’s hard not to take that personally.

And finally, I don’t think I can forgive the USPSTF for making me agree with Newt Gingrich. To me, that’s the strongest indication of all that the USPSTF is very, very wrong.

Leave a Reply