The Blood Test Many Oncologists Don't Order
Three years cancer-free, I'm not using ctDNA screening. Amy Delson, four cancers in, fought to receive ctDNA screening. The point is that patient should have a choice.
Amy Delson can’t have mammograms anymore. After four cancers and three rounds of breast cancer treatment — she’s in active treatment right now — her body has reached a limit her oncology team can’t argue with.
So she did what most patients don’t know they can do. Her community oncologist could not order it due to limitations imposed by the health system's policies. Amy was able to get circulating tumor (ct) DNA tests through a researcher she works with. ctDNA is a blood test that can detect cancer recurrence months before imaging would show it.
She’s not the only patient who’s had to do that.
I’ve been getting questions from survivors for the past year about Signatera, Oncodetect, FoundationOne, and a wave of new tests that hit the market faster than most community oncology practices can keep up with. At the cancer genomics conference at the University of Chicago last week, I saw the next wave coming. The science isn’t standing still.
For the record, I haven’t taken any of these tests. Three years out from triple-negative breast cancer, my statistical recurrence rate is genuinely low, and I have exams every six months. The immunotherapy I had as part of my treatment continues to do its work. That’s the right call for me.
It would be the wrong call for someone else.
That’s the whole argument of this week’s episode of Kicking Cancer’s Ass. Not whether ctDNA testing is good or bad. Whether the patient gets to decide.
Most oncologists won’t offer it. The reason, when you press on it, isn’t that the science isn’t real. It’s that they don’t think the average patient can handle an ambiguous result. Amy has a sharper view. She’d interviewed a fellow advocate who told her: we want to know everything we can know. Tell us straight, be transparent, and then let us decide.
Two things to take from this conversation:
The science around ctDNA is moving fast and it’s pathology-specific. What’s true for one cancer type this year isn’t true for another. Ask your oncologist whether they keep up with the cutting edge for your pathology. If you can’t get a clear answer, get a second opinion from someone who does.
The tests are imperfect, and that’s not a reason to withhold them — it’s a reason for honest informed consent. Not every tumor sheds DNA into the bloodstream. Some cancers are non-shedders, which means a negative result might not mean what you think it means. As we age, healthy blood cells can develop mutations that mimic cancer mutations, which means false positives can drive real fear and unnecessary biopsies. A patient who knows all of that is in a better position than a patient who isn’t told the test exists.
This week’s full episode is with Amy Delson, recorded at RiseUp 2026. We get into what ctDNA can and can’t tell you, why your community oncologist may not have heard of it, and what’s coming in the science.
The subscriber article this week goes deeper on the SERENA-6 trial — the phase 3 study that just changed what “clinical utility” means for ctDNA for metastatic disease and response to treatment — and on the questions to bring to your next oncology appointment.
🎧 New episode out now: Apple | Spotify | YouTube
📰 Subscriber article: link