Cancer is not a moral failure

Back during the Cold War, cancer was often compared to communism, and vice versa. Seriously. It was during the height of those hostilities, in the early 1950s, that the British epidemiologists Richard Doll and Austin Bradford Hill published two papers that clearly established the relationship of smoking to lung cancer. Although the idea had been around for some time, many eminent scientists, most notably R. A. Fisher, were convinced that Doll and Hill had it all wrong.

Of course they were right. Sadly, Epidemiology, my chosen profession, has not had a similarly important contribution to public health since, and likely never will.

Another unfortunate downstream effect of the smoking - lung cancer story is that cancer has become associated in many minds with risky behavior. If you have cancer, you must not have lived right. This is bullshit, and a moment's thought will tell you so. The majority of smokers do not get cancer (although smoking certainly causes cancer), so even among lifetime heavy smokers only the unlucky end up with lung cancer, or bladder cancer, pancreatic cancer, or one of the several other cancers caused by smoking. Even among smokers who get lung cancer, a (very) small fraction have cancer for some other reason (genetic susceptibility, radon exposure, unknown causes, . . .), and among ex-smokers and non-smokers this fraction is much larger (100% of non-smokers, of course). 

Sometimes risky behavior is mistaken for immoral or shameful behavior. Smoking is risky, in the sense that it increases your risk of many diseases and death. Mountain climbing is risky, too, but is rarely viewed as bad behavior. So maybe the distinction has to do with how these behaviors affect other people, but that doesn't work out either: secondhand smoke does affect the health of those exposed, but bad mountain climbing decisions often lead to multiple deaths, and essentially victimless behavior such as overeating gets put in the "bad behavior" category a lot more often than it gets put in the "heroic but crazy" category.

The public health community would like you to know that avoiding risky behavior of all kinds is better for everyone, which is true enough, all else being equal. But strangely enough we all get sick and die, even epidemiologists, and how and when we die is only affected in part by how we have lived. How big a part our behavior plays is impossible to say given what we know now. The sum of our ignorance about the full set of events that lead to cancer or any other way of dying has to be counted on the "bad luck" side of the ledger, since we can hardly know to avoid something that we don't know can hurt us. 

There's a lot of bad luck out there. If you come up with an algorithm for avoiding it, you will have made the greatest contribution to epidemiology since Doll and Hill, at least. Also, you should buy a lottery ticket.