She thinks we often underestimate the importance of the downside of screening. Several factors need to be weighed in controlled clinical studies to determine that balance, including the effects of false positives and false negatives, she said. Other considerations include whether the benefit for those whose disease is detected early balances the risks to those who are disease free and whether early detection and treatment actually improve outcomes. Because at first blush it's hard to see a downside to screening, many people don't understand how risks could possibly outweigh benefits. To illustrate that point, Malm uses an extreme example.
People die every year of acute appendicitis.
If all people were encouraged to get their appendix out before they were sick, we could save all those lives. The same comparison of benefits to risks needs to be done for screening. Until we know that the probability and size of benefit is enough to make that worthwhile, we shouldn't be encouraging it. Malm is not alone in suggesting caution in making screening recommendations. If people won't live longer or healthier as a result of detecting a disease early, he said, the test isn't warranted.