...AND CHEAPER...:

Wouldn't it be better to simply not find these cancers in the first place? We need another new strategy: Look less hard for cancer. Call it low-impact screening.

Consider the search for prostate cancer. PSA screening has been discouraged because it causes many men to be diagnosed with prostate cancers that are not destined to ever bother them. It has become the poster child for cancer overdiagnosis. But the problem is less about the assay itself and more about how we chose to use it.

Screening is not one thing; it's a process. A colleague once compared it to a machine with a lot of dials to adjust. There is a dial for what age to start testing, a dial for what age to stop, a dial for how often to test and a dial for what constitutes an abnormal test, which controls how aggressively doctors look for cancer during each test.

If we want to find fewer prostate cancers, the dial for what constitutes abnormality is the one we most need to readjust. At first, the dial was set at a PSA of 4. Below 4 was "normal"; 4 or above was "abnormal." A little more than a decade ago, some urologists argued that the dial should be turned down to a PSA of 2.5. That was the wrong direction. It led to more overdiagnosis.

Turn the dial the other direction. A higher abnormal PSA threshold would mean fewer men would be told they need a biopsy, reducing false alarms and overdiagnosis.

Urologists can better hone the group who should be biopsied with further adjustments: age-specific PSA thresholds, adjusting the threshold for prostate size and, most important, making use of the diagnostic value of time, measuring how fast PSA is rising. Such adjustments should be guided by data, so that the number of men told they require intervention more closely approximates the number expected to develop serious cancer.

Because the PSA test produces a single number, it's easy to see where the abnormal test dial is set. It's harder for thyroid and breast cancer tests because they use images to search for cancer.

But the dial is clearly being turned the wrong way in breast cancer. Everyone seems to be trying to find more, with 3-D mammography, molecular breast imaging and MRI imaging. And yet we know statistically that many, if not most, of these additionally discovered cancers will not develop into serious health problems in the next decade.

The way to find a more appropriate amount of breast and thyroid cancer is to forget about the small stuff, the tiny abnormalities. Turn the dial to focus on the larger abnormalities, perhaps a centimeter or larger. As the data come in, adjust the target size so that, again, the number of patients told they will need intervention more closely approximates the number that can be expected to develop serious cancer.

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