Scientific Medicine vs. Saving Lives

I have trouble understanding back surgery. All the data suggests that for most people with debilitating back pain, surgery does no more good than a week of rest followed by a program of exercise. But I have three acquaintances who are convinced that back surgery saved them from a life of pain. They all say that they felt better within a week of surgery than they had felt in years.

What's going on with that?

That was a rhetorical question, because nobody really knows the answer. We see the same thing in the debate over breast cancer exams. The data show that for women under 50, breast cancer screening does no good. But everybody knows somebody who is convinced that her life was saved by early detection of cancer, either by a mammogram or a physical exam. One of the commenters on the NY Times health blog said that she found a marble-sized lump in her breast, and that immediate treatment saved her life. The numbers, though, suggest that somehow she is wrong. Why?

Two things come to my mind. The first is that Americans do not have a sufficient appreciation of how dangerous hospitals are. The whole apparatus of medicine -- gleaming buildings, highly credentialed doctors, devoted nurses, digital machinery -- makes people feel safe. It shouldn't. Hospitals are actually very dangerous places, crawling with antibiotic-resistant bacteria, full of marginally competent people whose errors kill 100,000 Americans a year. So anything that sends people to the hospital who don't need to be there poses a real danger to our health.

The second is that we don't understand cancer nearly well as some people think. The general perception is that cancers start in one place, where a tumor grows, and then at some point spread around the body; they key to successful treatment is to remove the tumor before the spread happens. But many cancers aren't like that. Some never spread at all, no matter how big the original tumor gets. Some have already spread before the tumor reaches the size of a pinhead. Our NY Times commenter probably had a slow-growing tumor that might never have threatened her life; if she had had a dangerous tumor, it would already have spread throughout her body long before it reached the size of a marble. I heard an oncologist on NPR speaking about a drive to screen for thyroid cancer. He said that this would little good, because most thyroid cancers are not dangerous and remain operable no matter how big the tumor gets, and the dangerous ones have usually spread through the body before the tumor could be detected by any method we have.

Americans seem to think that more health care is always better, so any plan to limit the amount of care people get is evil. But they are wrong.