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A tumour-informed blood test is built for one patient: the tumour is sequenced first and the test then hunts for that patient's own mutations in blood. A tumour-naive test uses the same fixed panel, often of methylation marks, for everyone, so it needs no tumour sample and returns faster.
Tumour-informed assays (Signatera, RaDaR) sequence the resected tumour, choose a set of clonal mutations, and track them in plasma at high depth, which gives high specificity and lets a positive be called on very few molecules; the cost is a tumour sample, a bespoke panel per patient and a longer first turnaround. Tumour-naive assays (Guardant Reveal and most multi-cancer tests) apply a fixed panel of mutations and methylation or fragmentation features to every sample, so they work without tissue and from the first draw, at the price of having to distinguish tumour signal from clonal haematopoiesis and other background. Trials so far have used tumour-informed tests for treatment decisions (DYNAMIC used a tumour-informed approach; IMvigor011 used Signatera), while screening tests are necessarily tumour-naive. Head-to-head sensitivity comparisons are few, and results are not interchangeable between assays.
Showing the technology this term belongs to: MRD / molecular residual disease testing.
The glossary entry explains the word; the readout page carries the scoring rule, the thresholds approvals use, the companion diagnostics and the tests.
Residual-disease testing may not need the tumour to be sequenced first, which would remove the slowest step of tumour-informed assays; the comparison with tumour-informed results in the same patients is the evidence that matters.
The blood test stratifies risk far better than stage or pathology. It supports treating ctDNA-positive patients and suggests ctDNA-negative patients gain little from chemotherapy, but because treatment was not randomised the de-escalation claim needs the randomised trials that are now under way.
It reframes the blood test from a yes-or-no residual disease result into a measure of how well chemotherapy is working and how fast a relapse is coming, which is what an escalation trial would need.
For stage II colon cancer, where most patients are cured by surgery alone, a blood test can identify the minority who benefit from chemotherapy and spare everyone else its side effects. It does not yet prove that treating ctDNA-positive patients improves survival compared with not treating them.
ctDNA clearance may refine pCR as a surrogate: a patient with residual disease but no ctDNA may not need escalation, the hypothesis behind ctDNA-guided post-neoadjuvant trials.
It showed that serial rather than single testing is what makes residual disease detection work, and it set the sampling schedule most later studies have used.
Minimal residual disease became measurable in solid tumours, and the DYNAMIC and CIRCULATE trials that followed turned the measurement into a treatment decision.
Shares CIRCULATE-US, IMvigor011, DYNAMIC: a blood test safely halved chemotherapy use after surgery for stage II colon cancer, DYNAMIC.
Shares Circulating tumor DNA analysis detects minimal residual disease and predicts recurrence in patients with stage II colon cancer, GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, DYNAMIC: a blood test safely halved chemotherapy use after surgery for stage II colon cancer, DYNAMIC.
Shares Circulating tumor DNA analysis detects minimal residual disease and predicts recurrence in patients with stage II colon cancer, GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, DYNAMIC: a blood test safely halved chemotherapy use after surgery for stage II colon cancer, DYNAMIC.
Shares BESPOKE CRC, CIRCULATE-US, DYNAMIC, Signatera.
Shares Analysis of plasma cell-free DNA by ultradeep sequencing in patients with stages I to III colorectal cancer, ctDNA MRD positivity (molecular residual disease after curative treatment), Signatera, Minimal / molecular residual disease (MRD).
Shares GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, IMvigor011, DYNAMIC, Signatera.
Shares IMvigor011, DYNAMIC, Signatera, Minimal / molecular residual disease (MRD).
Shares BESPOKE CRC, CIRCULATE-US, DYNAMIC, Signatera.