A doctor feels a patient's neck for lumps that could indicate thyroid cancer
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The results showed Mold's PSA was elevated, which typically leads to a biopsy. But Mold was not typical. He understood the test's limitations. So he reread the medical literature on the subject and consulted his colleagues. He avoided sex and treated himself with antibiotics, both of which would have brought his PSA levels down in the absence of cancer. He had another PSA test. Elevated. So he opted for a biopsy. Cancer. Prostate cancer is often slow-growing, so some patients choose watchful waiting over surgery or radiation.
"I was trying to imagine myself living — hopefully 40 more years — with a cancer growing inside of me," remembers Mold. He knew that surgery or radiation could end his sex life and impair his ability to urinate. He knew studies showed that there was a good chance his cancer would never hurt or kill him. Still, he says, "I couldn't resist." He had his entire prostate removed. "I've done really well, and I'm really grateful that I had it done, but I don't know if it was needed," says Mold, now 62. "They say, 'Well, we can stop at any point.' No, you really can't."
Ironically, when he was a young doctor, Mold was one of the first clinicians to write about "the cascade effect," in which patients enter the health care system for one problem or even routine testing and end up getting shuttled through myriad related or unrelated interventions. This can happen in virtually any area of medicine, but cancer screening is particularly risky territory because healthy people are often caught in the net. "Once you've committed to testing, it makes sense to commit to everything else," Welch says. We all imagine we could be the 1 in 1,000 or 1 in 10,000 whose life could be on the line.
"The most important decision is whether or not to be screened," says Dr. Matt Handley, a family doctor and associate medical director for quality and informatics at Group Health, a Seattle-based health-and-insurance system with a zealous adherence to care based on hard evidence.
The chances of getting caught in a diagnostic cascade are increasing thanks to advanced imaging technology. For colorectal cancer, in addition to screening tests that analyze feces and survey the colon internally, there is now virtual colonoscopy. This screening method uses radiation, via CT, to view the organ from outside the body and reconstruct it digitally. CT colonography, as it is called, has advantages. No sedatives are required, and a patient can skip the part in which a doctor threads a scope and light through the rectum. The procedure is also cheaper than a colonoscopy. Whatever savings colonography might appear to present, however, are far outweighed by the cost of following up on all the abnormalities that can show up in the resulting images. These discoveries are known in the medical field as incidentalomas and are typically harmless. As many as 16% of patients undergoing their first virtual colonoscopy are found to have them. Cue the cascade.
Incidentalomas take up so much time, energy and money that some doctors are questioning whether imaging technology has advanced too far. Some doctors are even ignoring the images of the rest of the abdomen created by a CT colonography. They don't want to look, for fear of what they might find. At the same time, imaging-equipment manufacturers are creating higher-resolution scans, increasing even further the chances that something innocuous could be found.
Dr. G. Scott Gazelle, a radiologist at Massachusetts General Hospital who has a Ph.D. in health policy, points out that higher-resolution CT scans require more radiation. "We're starting to question how good the images need to be," he says. Efforts are under way at many hospitals to reduce radiation dosage, but this follows more than a decade of sharp increases. Radiation exposure is part of the reason the USPSTF says it cannot determine whether CT colonography causes more harm or benefit; it assigned the procedure an I rating for "insufficient evidence."
Incidentalomas have the potential to cause even more upheaval for people who undergo CT to screen for lung cancer. Gazelle says there's no doubt that these scans, while exposing patients to many times the radiation of a chest X-ray, can reduce lung-cancer mortality in smokers and former smokers. (A randomized trial to assess lung-cancer-screening CT is under way.) "The question is, At what cost? And by how much?" he says. In addition to the staggering expense of tracking down all the incidentalomas that are likely to be found — lungs are notoriously full of such strange-looking nodules — the physical risks are high. Three to five percent of people who undergo surgery to cut out pieces of their lungs die from the procedure. "Multiply that by the smokers and former smokers in the U.S. population and you could get tens of thousands of deaths," says Gazelle.