Early detection of cancer is the best chance of a cure, right? Maybe not.
A growing body of counterintuitive evidence suggests that some cancer-screening tests —including those for breast, prostate, colon, lung and cervical cancer — may be unnecessary and, worse, can do more harm than good.
“Most consumers have the belief that more screening is better, but screenings result in many false positives, which can lead to unnecessary worry, more testing, excessive costs and, worse, actual harm, even death,” said Dr. Gil Welch, a professor of medicine at Dartmouth College and author of “Overdiagnosed: Making People Sick in the Pursuit of Health.”
“There are two sides to this discussion, but only one gets heard. The other side is that you have to involve many people and harm some to help one,” Welch said.
The collateral damage is what people ignore, Welch said: “We’re overstating the benefit and understating the harm.”
Dr. Otis Brawley, chief medical officer of the American Cancer Society, agrees.
“We have a group that gets too much health care and receives interventions that are not necessary, are of no benefit and can cause harm,” said Brawley, an oncologist and author of “How We Do Harm: A Doctor Breaks Ranks About Being Sick in America.”
They make a very good point, said Dr. Clarence Brown, emeritus president of MD Anderson Cancer Center Orlando (Fla.), who now heads oncology development for the Orlando Health Foundation.
“It’s a fine line between whether you’re doing good or harm,” Brown said. Still, he considers himself “a proponent of screening.”
What’s important, said Brown, is to put risks in perspective and to look at an individual’s chances of developing a particular cancer.
Consumers have been taught, and logically assume, that early screenings lead to early detection, which leads to better outcomes.
“We try to find more cancers because we think if treated early that will improve outcomes,” said Dr. Kenny Lin, associate professor of family medicine at Georgetown University School of Medicine. “But there is no evidence whatsoever that just because you find more cancer, that will lead to improved outcomes. It often leads to worse outcomes, especially when screenings find cancers that aren’t lethal.”
The problem, experts agree, is knowing which cancers will kill you and which you can live with. Some cancers don’t matter. Some regress.
“A big problem with cancer screening is that we treat everything like it’s going to kill you,” Lin said.
Much excess testing is done because patients insist, Brawley said.
Plus, screenings are good for business.
“Patients need to be wary of the interests involved,” Welch said. “Health centers need to find ways to pay for the expensive diagnostic equipment, and screenings are a good way to capture business.”
Brown agrees that physicians probably do over-treat because “we have a fear of being sued.”
However, he said, “over the 35 years I have watched cancer screening evolve, I know we have caught cancers through screening. When you’re on the firing line, it’s better to say, ‘Have that test.’ ”
Finding cancers earlier also leads to what researchers call lead-time bias, which skews survival rates. Detecting a cancer early that a patient dies from anyway doesn’t mean he lived longer, only that he lived longer with knowledge of the disease, experts say.
The problem with the guidelines is that one size doesn’t fit all, Brown said. “Some of this is about how medicine is an art versus a science. We need to use a lot of intuition and conversation instead of just screening and treatment.”