Whose Test Is It Anyway?
The patient-choice argument behind ctDNA, the trial that just changed what "clinical utility" means, and what to bring to your next appointment.
There’s an argument inside oncology right now that almost never gets made out loud.
Most oncologists believe the average cancer patient can’t handle ambiguous information. They believe that when faced with a test result that says something is here, but we’re not sure what it means, and we’re not sure what to do about it, most patients will spiral. They’ll demand action when no action is warranted. They’ll lose sleep, lose function, lose perspective. The kind thing, the protective thing, is to not order the test in the first place.
I understand the impulse. Amy Delson, this week’s guest on Kicking Cancer’s Ass, knows it better than most, she’s been treated for cancer four times, and she’s in active treatment right now.
But the argument has a hole in it, and Amy was the one who showed me where. She’d interviewed a fellow breast cancer advocate who told her: we want to know everything we can know. We have young children at home, we have our jobs, but you have to really explain it to us in a way we can understand. And then let us decide.
Your Blood Shows Cancer Is Back 8 Months Before a Scan Does (Episode #45): Apple | Spotify | YouTube | Everywhere
The patient is not the problem. The patient is the one who knows what trade-offs she’s willing to make.
What ctDNA actually is, in plain terms
Circulating tumor DNA is exactly what it sounds like. When some tumors shed cells into the bloodstream, those cells release DNA. That DNA can be detected through a blood draw and matched against either a tumor sample or a panel of known cancer mutations. If the test finds tumor DNA in your blood, you’re “ctDNA positive.” If it doesn’t, you’re “ctDNA negative.”
Tests on the market right now include Signatera, Oncodetect, and FoundationOne, with new entrants arriving regularly. At the cancer genomics conference at the University of Chicago in April 2026, I saw the next wave coming.
