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.
So she did what most patients don’t know they can do. While the optimal way for patients and research is to participate in a randomized clinical trial, she was not eligible for any trials. 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 may 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 other new tests that hit the market faster than most community and even academic oncology practices can keep up with. At the cancer genomics conference at the University of Chicago last week, I saw the next wave coming. 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 might 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; but whether the patient has the opportunity to decide.
Even the best oncologists in the US don’t offer ctDNA tests because they have not been validated for clinical utility in a clinical trial. That means that test results are not linked to a change in therapy that could prolong life. The patient may want the test anyway, but they need to be informed about what it might and might not provide. Many doctors are concerned that an ambiguous and non-actionable result will create more stress for their patient. Amy has a different perspective. 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 molecularly-specific. What’s true for one cancer type this year may not be true for another. Please ask your oncologist whether they stay current with the latest in the molecular basis of your disease. If you can’t get a clear answer, get a second opinion from someone who does - you may need to use Telehealth from a cancer center such as MD Anderson or Memorial Sloane Kettering.
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, so a negative result might not mean what you think. 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 why even academic oncologists don’t prescribe it, Participating in clinical trials to validate the clinical utility of the test is crucially important to move the science forward.
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