Postoperative circulating tumor DNA combined with consensus molecular subtypes can better predict outcomes in stage III colon cancers: A prospective cohort study

•ctDNA was detectable in 15.9% pre-chemo and 8.9% post-chemo sample.•About 54% of positive ctDNA cases recurred, while 21.3% of negative cases recurred.•Sixty percent of CMS4 tumors recurred, while only 21% of CMS1-3 tumors recurred.•Redefined risk of ctDNA, CMS and clinical risk is a better prognostic biomarker.•High-/mid-risk cases were 14.6 and 5.3 times more likely to recur than the low-risk.