Circulating tumour DNA in early stage colorectal cancer: can blood tell all?

The decision to offer adjuvant chemotherapy after primary resection for non-metastatic colorectal cancer (CRC) is principally guided by histopathologic parameters. However, this approach lacks precision with many patients potentially receiving unnecessary treatment. For example, only about 1 in 20 patients with stage II colon cancer will benefit from adjuvant chemotherapy (1). In large part, this is due to the lack of prognostic biomarkers to precisely stratify patient risk and to guide a personalised approach to treatment. Additionally, for the past 15 years there has been no progress in developing more effective adjuvant therapy beyond oxaliplatin and fluoropyrimidine (2-6).