By Heather Millar
As most cancer patients are probably aware, there are several ongoing debates about cancer screening in this country. There’s disagreement about whether to screen for prostate cancer, and whether to treat it immediately if you do find it. There’s disagreement about screening for lung cancer: does screening actually catch those cancers that can be successfully treated? And there’s seemingly endless debate about breast cancer screening: Should women start at 40 or 50? Should they have mammography screens every year or every other year? Should they worry more if they have dense breasts?
A couple of headlines in the past week brought this all to mind:
- First, one national study of more than 900,000 patients concluded that screening women aged 50 to 74 every other year for breast cancer seems to be as effective as yearly screening. This seems to be true even if those women have dense breasts (which increases their cancer risk). The same team, researchers from the University of California at San Francisco and Seattle-based Group Health Research Institute, reported similar results last year, for women aged 66 to 89.
- Another study, also out of UCSF, reported on a simple checklist that doctors might use to gauge the likelihood of an elderly patient living more than 10 more years. The checklist poses queries like this: Do you use tobacco? Do you have a low body mass index? Do you have diabetes, congestive heart failure or chronic lung disease? The more times you answer yes, the greater of your risk of dying in the next decade.
While the researchers point out that this checklist is not a crystal ball, they say that they hope the checklist can help doctors to decide if preventative measures, like cancer screening, make sense for particular patients.
I can already hear the clickety-clack of readers typing outraged responses to these two studies. How dare doctors handicap my life like a golf tournament? How dare they limit screens for this or that cancer? Those screens saved my life, my spouse’s life, my child’s life! (They saved my own life, by the way.) Don’t they realize they’re talking about people’s lives here?
Actually, I think doctors are acutely aware that they are dealing with people’s lives. I think the misunderstanding comes down to a fundamental truth stated by, strangely enough, the Russian dictator Joseph Stalin: “One death is a tragedy; a million is a statistic.”
Doctors pledge their lives to fight death, one person at a time. But the science they use to guide their actions relies upon statistics: averages of hundreds, thousands, even hundreds of thousands of individual cases.
Doctors are constantly balancing the particular, the patient in front of them, with the general, what the studies say, what the treatment protocols are. How does the benefit of this one patient stack up against the cost, the risk, or the misery of whatever test or treatment is being considered? At a society-wide scale, does the benefit of this or that test justify the cost?
In my experience, people hate to hear this. When your life is in the balance, the last thing you want to consider is that your doctor is weighing your chances against averages and studies and budgets.
But I think we patients should try to remember how difficult it is to pull off this balancing act we demand of doctors. Each day, a physician’s mind must go from general to particular, from particular to general and back again, over and over. Docs don’t always do it perfectly. Studies don’t always accurately approximate reality. Hence I’m sure these screening debates will continue.
Just remember: One person’s experience is not enough to change medical practice, the average of many experiences is.