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Japan's national programme tests whether a blood test after surgery should decide who gets chemotherapy, and whether treating a positive test early helps.
GALAXY (observational, >2,000 patients) showed ctDNA positivity 4 weeks post-surgery is the strongest predictor of recurrence (Nature Medicine 2023). ALTAIR (ctDNA-positive, randomised to trifluridine/tipiracil vs placebo) missed its DFS endpoint (2024), suggesting late-line chemotherapy does not clear MRD. VEGA (ctDNA-negative, omit vs give CAPOX) is ongoing. Together with DYNAMIC these define the state of ctDNA-guided adjuvant therapy in CRC.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
Primary endpoint not met
Sourcen = 1,039 resectable stage II-IV CRC; ctDNA positivity was the strongest prognostic factor and identified who benefited from adjuvant chemotherapy (HR 6.59)
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| GALAXY (observational): recurrence risk by post-operative ctDNA status (4 weeks after surgery) | ctDNA-positive | - | n = 1,039 resectable stage II-IV CRC; ctDNA positivity was the strongest prognostic factor and identified who benefited from adjuvant chemotherapy (HR 6.59) | 10 | <0.0001 | link |
| ctDNA-negative | - | - | ||||
| ALTAIR (randomised phase 3): disease-free survival in post-adjuvant ctDNA-positive patientsprimary | Trifluridine/tipiracil | 122 | 9.3 months | 0.79 (0.6 to 1.05) | 0.107 | link |
| Placebo | 121 | 5.55 months |
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.
It is the proof that plasma genotyping can enrol patients for a targeted colorectal trial, which matters most for a 2 to 3% alteration where archival tissue is often exhausted or out of date.
Shares Jeanne Tie, ctDNA-guided adjuvant therapy as the default in stage II-III colon cancer, GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, Take ctDNA-guided de-escalation beyond stage II, and stop escalating on a positive result until a trial says it helps.
Shares ALTAIR, DYNAMIC-III, CIRCULATE-US, Signatera.
Shares Jeanne Tie, Take ctDNA-guided de-escalation beyond stage II, and stop escalating on a positive result until a trial says it helps, DYNAMIC, Signatera.
Shares Circulating tumor DNA in stage III colorectal cancer, beyond minimal residual disease detection, toward assessment of adjuvant therapy efficacy and clinical behavior of recurrences, CIRCULATE-US, GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, DYNAMIC.
Shares A national platform trial that every ctDNA-positive patient can join, Formally qualify tumour-DNA blood tests as a surrogate endpoint for adjuvant trials, Signatera, Diagnostics roadmap: stains → gene panels → blood tests that decide treatment.
Shares CIRCULATE-US, GALAXY: tumour DNA in blood four weeks after bowel cancer surgery predicts relapse tenfold, Take ctDNA-guided de-escalation beyond stage II, and stop escalating on a positive result until a trial says it helps, Signatera.
Shares Formally qualify tumour-DNA blood tests as a surrogate endpoint for adjuvant trials, CIRCULATE-US, DYNAMIC, Signatera.
Shares DYNAMIC, Signatera, Dormant cells and minimal residual disease, Minimal / molecular residual disease (MRD).