Double Espresso vs Prostate Cancer

Andrew J. Vickers, PhD


December 17, 2010

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Andrew J. Vickers, PhD: Hi. It's Andrew Vickers, a biostatistician at Memorial Sloan-Kettering Cancer Center, back out on the streets of Brooklyn. It's a beautiful fall day in Brooklyn. I'm standing at the end of my block. I've got the farmer's market behind me. If you came to Brooklyn from some foreign country, you might get the impression that we're obsessed with coffee. You can get a nice coffee over there at Belleville. Two or 3 doors that way is Perch Café. They have music in the evenings, but you can get a nice latte there. There's a bodega there, which is coffee 24 hours a day, and it goes on actually.

We've got Café Martin right here. That's kind of your gourmet coffee. There's Willy's Hot Dogs. You can always get a coffee at Willy's, and also at Joe's Pizza. There's Bagel World up there. That's for your early morning coffee. Snice is a bit further on. That is a food place, but there is lots and lots of coffee at Snice. The question is, why? Why is everyone drinking coffee? I've got my coffee and my work. I just need to find someplace quiet to drink it.

Anyway, I've got some research I'm reading here. This is from the Channing Laboratory at Harvard University, and this is research saying that coffee can reduce your risk of advanced prostate cancer by 60%.[1] That's important because although many men get prostate cancer, for most men it's not actually that harmful. Obviously, the advanced prostate cancers are the sort of cancers that can actually effect a man's quality of life or cause him to die early from prostate cancer. Drinking the coffee might reduce your risk for death from prostate cancer.

We've got someone drinking coffee there. Excuse me, excuse me, you've got coffee there?

Female Voice 1: Yes.

Dr. Vickers: Why are you drinking coffee?

Female Voice 1: Because I'm tired.

Dr. Vickers: Okay. Did you know that drinking coffee can help prevent advanced prostate cancer? Just take a sip. Take a sip of your coffee. All right. I will personally guarantee you will never get advanced prostate cancer. Okay? It's going to work. It's going to work. Trust me.

Dr. Vickers: This wasn't a randomized trial. It was epidemiologic observational research. What they did was they gave people a questionnaire about their coffee drinking habits, and then they correlated that with hospital records on who got advanced prostate cancer and who didn't. Of course, there's a big problem with doing that type of research, which is that people who drink coffee may be different from people who don't drink coffee in all sorts of ways other than their caffeine consumption. Here's the number-one reason I don't actually believe the study. What the investigators reported was a 60% decrease in your risk for advanced prostate cancer if you drank coffee. Finasteride and dutasteride, these are drugs that we know in randomized trials are effective for prostate cancer, and we know that they have a mechanism of action that is pertinent to the prostate. Those 2 drugs reduce the risk for cancer by about 25%. Nothing is going to reduce the risk for advanced prostate cancer by 60%. I doubt if chemotherapy would. This is just a guess, little indication that the results of the study are due to bias.

There's another problem with these sorts of studies. Cancer takes a long time to develop. In fact, in the case of prostate cancer, we know that it takes 30 or more years between initiation of cancer and a clinical diagnosis. Instead of asking someone, do you currently drink coffee and if so how much, you really need to follow people up over decades, asking them the whole time how much coffee they're drinking, which isn't really what people do.

I'm Andrew Vickers. I'm a statistician at Memorial Sloan-Kettering Cancer Center, enjoying some coffee, but I don't think it's going to do much for my prostate.


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