Questions remain about how to interpret MCED test results. Only certain blood tests can determine which organs are actually cancerous. Lab tests must be done on potentially cancerous tissue to confirm the diagnosis, but you can’t biopsy someone’s entire body. False positives remain a problem for the entire field of cancer screening, which, by design, involves sifting through piles of healthy tests for cancer. Galleri — the farthest MCED on the road to widespread use — falsely flagged 57 healthy blood samples as cancer in the aforementioned study.
There’s also the risk of jumping the gun — some cancers never become invasive or life-threatening, but early detection can help with treatment as harsh as chemotherapy. Some data suggests that cancers that are less worrisome actually appear in less blood, which could mitigate that problem.
The NIC trial will help determine how to interpret blood test results for cancer, and it will provide a standard approach to kickstarting cancer screening studies as companies flood the field with new tests.
“I don’t think most companies tend to want to compare their tests directly,” Timothy Rebbeck, a professor of cancer prevention at Harvard. “It is expensive and difficult. So someone else, a neutral party like the NCI, needs to do it.”
Rebbeck thinks the blood tests that the new trial will prove by veterinarians will be most helpful in cases of pancreatic, liver and ovarian cancers, the type of cancer that causes frequent deaths and has no form any other screening. However, longer trials are needed to confirm whether time to purchase these blood tests saves lives.
But Rebbeck is optimistic about Cancer Moonshot’s ultimate goal: “It seems very realistic to me to think that we can cut deaths in half,” he said.