One such study, appearing in the Annals of Family Medicine earlier this year and looking at prostate, colorectal, lung and ovarian cancers found that repeated screenings for cancers recommended by current protocols yield a number of false positives. After 14 tests, the chance of getting a false positive rose to over 60 percent of all men and nearly 49 percent of all women.
"I think the bottom line message is that traditionally, when people have gotten public health messages about screening, it's been oversimplified and presented in a positive light only," said Dr. Jennifer Miller Croswell, of the Office of Medical Applications of Research at the National Institutes of Health, one of the study's lead authors. "What we forget sometimes…is that these are medical interventions and they do have the potential for benefits and harms."
In a time when the costs of various treatments are put under the microscope during debate on health care reform, cancer screening presents an uncomfortable challenge, because setting a level of screening invariably leads to an acceptance that certain cases will be missed – thereby putting a dollar value on the lives lost.
"The problem with a false positive is that it can trigger this repeated long-term follow-up, and all these things add cost," said Croswell.
Ultimately, deciding how many false negatives to accept leaves the realm of medicine. "That's honestly a policy decision that can be made," said Croswell.