Chapter 85
Cancer — 12
Unfortunately, to date these tests are following the mass screening template of using age alone rather than integrating all an individual’s data to determine risk. There’s also the potential of combining tests to improve accuracy, such as cell-free tumor DNA sequencing and methylation, but that will raise the cost. One company that uses the fragmentation DNA assay has incorporated polygenic risk scores with its assessment, without added cost, which represents a step in the right direction.
For now, these tests are for the curious affluent and only carry potential value if positive, and only about half of those will be indicative of an actual cancer diagnosis that was not otherwise apparent. It will be primarily used by the same people who get executive health physicals with all sorts of tests that have not been validated in healthy people, at exorbitant costs.
That’s similar—without adequate proof of benefit—to the current use of whole-body MRI tests that are being heavily marketed. In the United States, Prenuvo and Ezra offer this for $2,500, with multiple endorsements by celebrities, like Kim Kardashian, and long waiting lists. Instead of theoretically spotting cancer at its earliest microscopic stage, MRI can only detect cancer once it exceeds a certain mass size; it’s macroscopic and even less likely to find a tumor early than the micro testing we’ve been examining. As with the person with a cancer signal from the Galleri test, an abnormal MRI sets off a cascade of more tests to determine whether there is cancer present, which can culminate in an organ biopsy, carrying risk. The chance that an abnormal MRI could promote “incidentalomas,” benign findings such as a nonmalignant nodule or cyst, is high: a meta-analysis of all the studies indicates that it occurs in at least 19 percent of people. That, along with the lack of sufficient evidence, is why the American College of Radiology recommends against total body–screening MRIs.
Dhruv Khullar, a young physician, underwent a whole-body MRI and was found to have a prostate lesion, which led to blood tests and a dedicated prostate MRI, and close surveillance that will include serial imaging and perhaps a prostate biopsy (and serial biopsies) in the future. Khullar’s physician told him, “Prenuvo probably views your story as a success—I view your story as a tragedy. They’ve created in your mind this uncertainty. You were a healthy person, and now you’ve become a patient.”