ATOMIC

In resected stage III dMMR colon cancer, does adding atezolizumab to adjuvant FOLFOX improve DFS?

Population and treatment

712 patients with resected stage III mismatch-repair-deficient colon cancer.

Intervention vs comparator: mFOLFOX6 for 6 months plus atezolizumab followed by atezolizumab to 12 months vs mFOLFOX6 alone for 6 months.

Registry: https://pubmed.ncbi.nlm.nih.gov/?term=ATOMIC+atezolizumab+dMMR+colon+cancer

Results

3-year DFS 86.3% vs 76.2%; HR 0.50 (95% CI 0.35–0.73; p<0.001). Grade 3–4 AEs 84.1% vs 71.9%. Later 5-year OS 89.7% vs 87.9%; HR 0.90 (95% CI 0.55–1.47), no demonstrated OS benefit.

Disease-free survival · 3 years

NNT: NCT02912559

NNH not calculated without a defensible fixed-time excess-harm risk. Never derive NNT from median survival or HR alone.

Toxicity and treatment burden

76.2

Full grade 3–5 toxicity, discontinuation, QoL and treatment exposure require primary-report/supplement extraction before full clinical signoff. Missing rates are not imputed.

Interpretation and limitations

Strong DFS effect in stage III dMMR disease, but no demonstrated OS benefit in cited later analysis. Do not generalize to pMMR/MSS cancer.

Distinguish prespecified from exploratory subgroups, mature from immature endpoints, and superiority from non-inferiority. Verify current guidelines and eligibility.

Primary source

Primary publication / authoritative source ↗

Source-level QoL, discontinuation, full toxicity and guideline currency audit remains a QC requirement.