- Adjuvant chemotherapy with a 5-fluorouracil-based regimen may benefit stage II patients with microsatellite instability-high (MSI-high) colon cancer tumors.
Why this matters
- Stage-specific analysis suggests benefit in high-risk stage II tumors.
- Population-based study (n=1010; 54% stage II, 46% stage III).
- Funding: German Research Council; Interdisciplinary Research Program of the National Center for Tumor Diseases; German Federal Ministry of Education and Research.
- Cox regression models using propensity score weighting showed adjuvant chemotherapy was associated with better cancer-specific survival (CSS; HR, 0.65; P=.002).
- MSI-high patients who underwent adjuvant chemotherapy had better CSS (HR, 0.36; P=.010) and trended toward better relapse-free survival (RFS; HR, 0.49; P=.070).
- Microsatellite stability patients who underwent adjuvant chemotherapy also had better CSS (HR, 0.65; P=.003) and RFS (HR, 0.68; P=.003).
- Stage II: 8% died, 17% had relapses, and adjuvant chemotherapy was associated with better CSS (HR, 0.26; P=.020) and RFS (HR, 0.38; P=.020).
- Stage III: Adjuvant chemotherapy was associated with better CSS (HR, 0.74; P=.040) and trended toward better RFS (HR, 0.78; P=.070).
- Retrospective analysis.