Introduction
CRC, toxicity, cancer, colon cancer, tumour, Colorectal cancer
CANCER, DISEASE, COLON CANCER, TUMOUR, COLORECTAL CANCER, MINIMAL RESIDUAL DISEASE (MRD)
Colorectal cancer (CRC) is the fourth most prevalent cancer in the UK accounting for more than 11% of all new cancer diagnoses [The 5 year disease free survival (DFS) for patients with stage II and III colon cancer treated with surgery without ACT is 81.4% and 49.0% respectively [In stage III disease, treatment with a FP reduces the risk of cancer recurrence by 41% [The UK SCOT study established that reducing ACT duration with CAPOX from 6 to 3 months did not compromise 3 year DFS and reduced the toxicity burden of treatment [Currently considerations regarding the need for ACT include histopathological features of the resected tumour and other patient factors such as age, comorbidities, PS and patient preference, leading to shared decision making. ctDNA has emerged as a biomarker for minimal residual disease (MRD) and can predict early relapse, offering a tailored approach to individual decision making [We hypothesise that ACT decisions guided by the post-operative ctDNA result will enable biomarker driven selection of patients who would and would not benefit from ACT, and thereby reduce the proportion of patients receiving ACT without compromising DFS. The primary objective is to demonstrate that a de-escalation strategy of ctDNA guided adjuvant chemotherapy is non-inferior to SOC chemotherapy as measured by 3 year DFS in patients with high risk stage II or stage III resected CRC with no evidence of MRD (i.e., those who are ctDNA negative post-operatively).