The morning headline is designed to make you nervous: Cancer deaths to double by 2030: study.
“My God!,” you reason to yourself before the coffee hits the bloodstream, “That means the chances are double that I’ll be stricken down by the Big ‘C’!” If you’re typical—and most of you are not—you will add: “Why doesn’t the government do something!”
Here’s the story, linked, I think appropriately, from Xinhua:
About 13.3 million people will die of cancer a year by 2030, almost double the number in 2008…The research, conducted by the International Agency for Research on Cancer (IARC), also indicated that almost 21.4 million new cases of the disease will be diagnosed annually in 2030.
In 2008, 7.6 million people died of cancer and there were an estimated 12.7 million new cases diagnosed…The IARC said the burden of cancer was shifting from wealthier to poorer nations.
There are at least five reasons why nobody should worry about this study. Coincidentally, they form the same five examples of how to cheat with statistics.
First, the obvious: it might be true that cancer rates will increase, and not just by two times, but by four, or eight, or even sixteen! Yes, everybody might die of cancer by next Tuesday. But it’s just not that probable. It’s most likely that things will continue as they have.
Here are the reasons why you should not become nervous:
- In 2008, there were about 6.7 billion of us prowling around the Earth. The IARC went out and counted everybody who died in that year, and placed a bean in a bag if that death was caused by cancer. At the end, they counted the beans: they told us there were 7.6 million of them. That’s a rate of 1.1 cancer deaths per 1000 people.
They claim that by 2030 13.3 million will die of cancer. However, in 2030 there will be almost another billion of us, so we’d expect that more people would die of cancer even in the death rate stayed the same. Given the expected population of 8.3 billion, the IARC figures that the cancer rate will be 1.6 per 1000.
This is an increase in the rate, all right, by about 1.4 times, but not a doubling. Still, any increase is bad news, right?
- Did you notice the plea to guilt in the story? Maybe you didn’t, especially since these pleas saturate the media and become part of the background noise. The study said, “the burden of cancer was shifting from wealthier to poorer nations.” Those poor poor people!
When people die, they die of something. You will die of something. The doc in charge of your carcass will check a box on a form that says “Heart Disease” or “Cancer” or whatever.
They cannot not check a box, at least here in the States. If you have multiple diseases, each of which contributed to your exit, still only one box will be checked. The doc will likely pick his favorite, or he will guess, not always correctly.
Mistaken causes of death are especially common in “developing countries”, where cancer is often undiagnosed. In other words, we expect that as technology and bookkeeping improve in these forlorn places, certain disease rates will “increase”, but only on paper. Thus, you cannot look at the increasing trend of cancer in developing countries as direct evidence that cancer itself is becoming more common.
Now, these facts imply that the 1.6 per 1000 rate should be adjusted down to account for increasing diagnostic accuracy. Say it comes to 1.3 to 1.4. Still higher than now. Still reason to worry?
- The “leading cause” of death nowadays is heart disease, not cancer. There will always be a leading cause of death, incidentally. Because of its number-one statues, a lot of money goes into curing heart disease: new cholesterol drugs come on the market weekly, it seems.
This means that as time progresses, fewer people will die of heart disease—but these hearty folks will still die of something, including cancer. Cancer rates will thus increase, but only because people won’t be given the opportunity to keel over on the subway with massive coronaries.
Improvements are being made in cancer treatments, too, but not as quickly as they are for heart disease. However, this evidence doesn’t allow us to lower our estimated cancer death rate, because it will be true deaths attributed to cancer will increase.
- We do not know what the death rate of cancer is with respect to other deaths. Our rates so far have been deaths per all people. What we’d like is deaths caused by cancer divided by all deaths.
- Lastly, we must ask ourselves this question: what are the chances that this United Nations organ charged with investigating cancer—its very livelihood is dependent on the disease—will, let us say, exaggerate the threat caused by cancer? To ask it is to answer it.