In medicine, some of the trickiest treatment questions arise out of diseases that are, in a zoomed-out statistical sense, not that dangerous. Prostate cancer is a prime example: For a long time, men have been instructed to regularly get tested for it once they hit a certain age. But most prostate-cancer cases progress very slowly. Sometimes, a watch-and-wait approach makes more sense than aggressive treatment, because that treatment itself can do more harm than the cancer would have, at least in the short term.
A new study published in the New England Journal of Medicine is the most ambitious effort yet to better understand the outcomes of different treatment options for prostate cancer. It followed, for ten years, a group of 1,643 men who had been diagnosed with early prostate cancer and who agreed to be randomly assigned to one of three groups: radiation, surgery, or so-called “active monitoring,” in which the patient stays in regular contact with a doctor who checks for prostate-specific antigen, or PSA, the presence of which is taken as a warning sign the cancer could be getting worse and it might be time for treatment.
The headline finding, summed up by Denise Grady of the New York Times, is that the researchers “found no difference in death rates” between men in the three groups over the span in question. Early treatment didn’t really do anything, in other words, in terms of reducing the odds of a patient dying. Now, that’s partly because prostate cancer tends to be a very slow-moving disease: Ten years after diagnosis, just 1 percent of the patients in the study had died.
The cancer “was more likely to progress and spread in the men who opted for monitoring rather than for early treatment. And about half the patients in the study who had started out being monitored wound up having surgery or radiation.” So from the point of view of an individual patient, if their doctor could have seen into the future he or she would have said something like this: We don’t need to do anything about this for now. A decade from now, you’ll be just as likely to be alive without having started treatment than if you had started treatment. If you don’t start treatment now, though, there’s a coin-flip chance you’ll have need to in the next decade
So setting aside cost and insurance issues, why not just treat right away, just in case? In addition to the fact that any treatment carries risks, treatment for prostate surgery can bring with it some significant quality-of-life issues: “Men who had surgery to remove the prostate were the most likely to have lingering impotence and urinary incontinence,” notes Grady. “Those given radiation reported bowel problems after six months of treatment (usually with gradual improvement) but not urinary incontinence. Sexual function also diminished after radiation, but recovered somewhat.” Although, further complicating things, “there were no differences among the three groups in anxiety, depression or their feelings about how their health affected their quality of life.”
One of the reasons these sorts of statistics are useful is that people have a lot of trouble with uncertainty and ambiguity, which can enact a psychological toll. All else being equal, there’s strong evidence to suggest that in all sorts of different situations, people will choose to take action rather than not take action, simply because of the sense of certainty such an act confers.
Studies like this help, because with this sort of data doctors don’t have to present treatment statistics on the one hand and a giant question mark on the other: They can lay out the ramifications of watching and waiting in more concrete terms. That’s not to say this reduces uncertainty to zero, of course, but it does help hammer home the point that sometimes, it’s better not to take quick, aggressive action against a potentially slow-moving medical threat.