DYNAMIC
Can postoperative ctDNA guide adjuvant chemotherapy in stage II colon cancer without compromising recurrence outcomes?
One underlying study; aliases and follow-up reports consolidated. Primary discipline: Biomarker.
455 patients with resected stage II colon cancer randomised to ctDNA-guided or standard management.
Curatively resected stage II colon cancer; do not automatically extrapolate to stage III disease or other assays/timing.
455 randomised/evaluable as reported.
Postoperative ctDNA testing at approximately 4 and 7 weeks; chemotherapy recommended for ctDNA-positive patients and generally omitted for ctDNA-negative patients.
Standard clinicopathological selection of adjuvant chemotherapy.
Endpoints and results
Primary endpoint 2-year RFS; secondary endpoints included chemotherapy use, 5-year RFS and OS.
- Adjuvant chemotherapy use about 15% vs 28%.
- 2-year RFS 93.5% vs 92.4%; prespecified non-inferiority criterion met.
- At median follow-up 59.7 months, 5-year RFS 88% vs 87% (difference 1.1 points; 95% CI −5.8 to 8.0%); 5-year OS 93.8% vs 93.3% (HR 1.05; p=0.887).
Absolute Effect and outcome visualisation
5-year RFS
% recurrence-free at 5 years · 5 years. Bars show reported fixed-time percentages.
Interpretation: Non-inferiority/de-escalation, not superiority. Do not calculate an NNT for the near-identical RFS rates; the main absolute effect is about 13 percentage points fewer patients receiving chemotherapy.
Toxicity, discontinuation and quality of life
Trial-specific harms: Chemotherapy toxicities are avoided in more patients; harms depend on the regimen used for ctDNA-positive patients.
Treatment burden/discontinuation: Reduced chemotherapy exposure is the key burden benefit. Do not infer unreported regimen-specific discontinuation.
Quality of life: No numerical QoL benefit claimed without a reported comparative estimate.
Subgroups, maturity and limitations
Subgroups: Postoperative ctDNA positivity is prognostic; ctDNA clearance occurred in 35/40 treated ctDNA-positive patients (87.5%).
Maturity: Five-year RFS and OS available.
Limitations: Modest sample size for OS; negative ctDNA does not mean zero recurrence risk. Assay and timing matter.
DYNAMIC supports reducing chemotherapy use without compromising the prespecified RFS criterion; it does not show superior OS.
Current-practice context must be checked against regional guidelines, patient fitness, biomarkers, alternatives and regulatory status before clinical application. Clinical freshness review and browser-rendered QA remain pending.
Primary sources and registry
Registry: ACTRN12615000381583 (Australian New Zealand Clinical Trials Registry; see primary publication linked above)
The Absolute Effect · Updated 26 October 2026 · Never derive NNT from median survival.