Cancer Screening Moves Upstream

Written By Doug Vanisky

Galleri is a blood test that screens for dozens of cancers at once. On September 23, an FDA advisory committee spent a day weighing whether this test from GRAIL should be approved. The vote was unanimous on safety. Seven to two, with one abstention, that the benefits outweigh the risks. Six to four on effectiveness.

A week later, on September 30, Abbott launched a blood test for colorectal cancer.

These two events a week apart point to the same thing. The blood draw is moving screening upstream of the symptom.

I once worked at a startup trying to do the same thing with exhaled breath. (No, not for drunk drivers.) It didn't make it, and I hold no stake in anything that did. Breath, blood, the body keeps telling us things before we feel them. Seeing the blood screenings finally get there, black turtlenecks in the rear view, is a meaningful step forward.

Because for most of medical history, diagnosis has been downstream. You feel something. Maybe you say something. Maybe the system has an answer.

But now, Galleri inverts that. No symptoms. (Not a biomarker dashboard, which wellness ventures have done for years.) Just a single blood draw at the age of 50 or older to answer the question: is there a cancer signal, and where? Then a signal, or not.

What the Trials Found

In a study of more than 35,000 adults, adding Galleri to standard screening protocol found ~3-6.5X (times) as many cancers, depending on which screenings you count. About 70% of the cancers it found have no routine screening test today. It also caught only about 40% of all the cancers diagnosed within a year. In the one randomized trial, run with England's NHS, stage IV diagnoses fell 14%. But the trial missed its main goal, which was to achieve a significant drop in overall late-stage cancers.

Does finding cancers earlier mean fewer people die from them? That's still an open question. According to published work by an expert panel convened by the American Cancer Society, fewer late-stage cancers is not yet a proven stand-in for fewer deaths.

With the mortality question unanswered, the FDA panel's 6-4 split on effectiveness came down to people, not an assay. The person with a positive signal and no cancer. The person with cancer and a negative signal who decides to skip the colonoscopy. The 15-minute primary care visit that already has to cover blood pressure, weight, and vaccines … and now a conversation about a test that almost never throws a false alarm, but misses more than half of what it's looking for.

Those are the questions a patient asks in the car afterward. Especially when they leave confused.

Experience as an Answer

Abbott's launch shows what answering these types of questions looks like. SimpleScreen CRC, developed by Freenome, catches about 80% of colorectal cancers and is covered by Medicare for average-risk adults 45 and older. The American Cancer Society recommends blood tests for people who decline or don't complete a colonoscopy or a stool test.

That distinction matters more than it sounds. A 2024 modeling study in Gastroenterology found blood-based colorectal screening worth it compared to no screening, but not compared to a stool test or colonoscopy, even if more people take it. The blood test only wins when it reaches someone who was never going to get screened otherwise. Offer it to the wrong person and you're trading a better test for a more convenient one.

So Abbott didn't just launch a test. It built an entire experience around it. Mobile phlebotomy at home, insurance support, translation services, and screening reminders. As Jake Orville, senior vice president of Abbott's cancer diagnostics business, said, "More screening options for colorectal cancer only matter if we help more people get screened."

Making It Routine

Every screening test that became routine got there the same way. Mammography, colonoscopy, PSA. The evidence was there, but it was the conversation that moved people. Advocacy groups made the disease speakable. Physicians learned to explain risk in a sentence instead of a lecture. Patients started asking about it by name. It took decades, and the science was the fast part then, too.

Blood-based screening is entering that conversation at a sprint, with patients who are more health-literate, more data-hungry, more optimization-obsessed, and more willing to act on a result they don't fully understand than any screening public before them.

Future Decisions

As of this writing, the FDA hasn't decided on Galleri. Approval, when it comes, will put the agency's weight behind a test doctors have been able to order since 2021. It won't decide who pays for it, and it won't decide who takes it. That gets decided in small moments: a doctor with four minutes left in the visit, a reminder text, a 52-year-old who feels fine deciding whether to look for something that isn't bothering her.

Breath-based screenings are a few years behind. As confounder and environment challenges are solved, they’ll hit the same rapids. Not in the lab, but in the exam room. If there’s a room.

Science moves upstream quickly. Conversations take longer to get there.

SOURCES

Doug Vanisky https://dougvanisky.com
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