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Making Treatment Decisions

Posted 1/24/2013

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    Although I plan to share an amusing essay from about making treatment decisions, this is a very serious topic. Let's start with the reality that most of us feel our brains shut down and our eyes glaze over pretty quickly during serious cancer conversations. I have a strong recollection, moments after being told of my first diagnosis, of thinking that my surgeon was kind of like looking at a fish in a tank--she was opening and closing her mouth, and I expected that words were coming out, but I was not hearing a single one. Even if you can stick with the reality better than I could that afternoon, none of us can make much sense out of a flood of statistics.

One core truth about statistics is that they are meaningless for any one person. We are each the 0% or the 100%, Starting from there, we try to follow the conversation and the logic and make the sensible choices for ourselves--all the while, anxious and sad and very overwhelmed. This article lays out this scenerio in a delightful way:

What Homer Simpson Can Teach Oncologists About Math

by PETER UBEL • JAN. 11, 2013
Let’s warm up with a quick arithmetic problem, which I want you to do in your head.

What is one thousand plus forty?

Now add another thousand

And thirty more

Plus twenty

And finally, add an additional ten.

What’s the answer?

According to Dean Buonomano, in his excellent book Brain Bugs, the majority of people give an answer of five thousand, instead of the correct answer of 3100.

“Most of us can find a face in the crowd faster than we can come up with the answer to eight times seven. The truth is—to put it bluntly—we suck at numerical calculations.”

I discuss this problem of innumeracy in my book Critical Decisions: “Throw enough numbers at people and many will experience negative emotions, emotions that often interfere with their ability to make good choices.” I focus on these math problems because, for some very important medical decisions, the right choice depends on grasping some basic mathematics. And perhaps nowhere in medical care is there more math—more explicit discussion of numerical probabilities and five-year survival rates—than in the care of cancer patients. Consider this snippet of a hematologist trying to explain that there is a good chance a patient’s leukemia will respond to chemotherapy:

“So if you look at complete cytogenetic response rates in the chronic phase,” the hematologist explains, “it’s about 80%, and if you look at the accelerated I re-enact a bit more of this conversation in one of my book-related videos, which you can find here. But let it suffice to say for now that this visit goes on for quite a while, with a staggering number of numbers being thrown at this patient. But even in this short paragraph, the hematologist moves rapidly from response rate percentages to progression percentages—in the former, high numbers being good, in the latter, high numbers being bad. A very confusing switch around for patients to follow, in the context of what is no doubt an emotional clinical encounter.

Which raises a question: Why all this talk about math with patients? Shouldn’t all this number stuff be handled by physicians? Shouldn’t chemotherapy decisions be made by medical experts?

As it turns out, many such decisions depend strongly on patient preferences. Suppose that chemotherapy increases a patient’s odds of five-year survival from 30% to 35%, but that same chemotherapy also increases the chance that person will die in the next six months, from treatment complications. Should the patient take this chemotherapy? There is no simple medical answer to this question. The answer depends on this individual patient’s preferences for long-term versus short-term survival, with additional consideration for the burdens of chemotherapy. Making the right decision often means coming to grips with some math.

In future posts, I will show you some of the work I have done to make this math easier to understand. But meanwhile, let me leave you with another quote from Brain Bugs:

Only one adequate response I can give to that, as a physician who no doubt has overloaded many of my patients with too much complicated math

D ’OH!”

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