Tracking Mutations in Cell Free Tumour DNA to Predict Relapse in Early Colorectal Cancer

TRACC Part B Inclusion Criteria: * New diagnosis of histologically confirmed CRC scheduled to undergo surgery with curative intent, with no radiological evidence of metastatic disease. * Patients with high grade dysplasia whose imaging is suggestive of colorectal carcinoma (CRC) will be included but will be excluded post-surgery if carcinoma diagnosis is not confirmed * Age≥18 * Ability to give informed consent * Able to adhere to follow up schedule TRACC Part B Exclusion Criteria: * Scheduled to have neoadjuvant chemotherapy, (neoadjuvant chemoradiotherapy for patients with rectal cancer is permitted) * Current or previous other malignancy within 5 years of study entry, except cured basal or squamous cell skin cancer, superficial bladder cancer, prostate intraepithelial neoplasm, carcinoma in situ of the cervix or other non-invasive malignancy TRACC Part C Inclusion Criteria: 1. Subject ≥ 18 years of age 2. Subjects with histologically proven high risk stage II or stage III colon or rectal cancer treated with curative intent with surgery alone (any T, N1 or N2) with no evidence of metastatic disease. High risk stage II is defined as having one or more of the following: T4 disease, obstruction and/or perforation of the primary tumour during the pre-operative period, inadequate nodal harvest as indicated by \<12 nodes examined, poorly differentiated grade on histology, perineural invasion, peritoneal involvement or extramural venous/lymphatic invasion. Subjects must be due to receive adjuvant chemotherapy after surgery or Subjects with histologically proven locally advanced stage III rectal cancer treated with neoadjuvant chemoradiotherapy (any T, N1 or N2, M0) with no evidence of metastatic disease are eligible. Subjects must be due to receive adjuvant chemotherapy after surgery 3. Fully surgically resected tumour with clear resection margins (i.e., \>1 mm). 4. Adequate organ function * Absolute neutrophil function ≥1.0 x 109/ L * Platelet Count ≥ 75 x 109 / L * Haemoglobin ≥80g/L (blood transfusion before randomisation is allowed) * Adequate renal function (GFR ≥ 50ml/min if single agent capecitabine or CAPOX being administered) as calculated by Cockcroft and Gault equation * Aspartate aminotransferase/ Alanine aminotransferase levels ≤ 2.5 upper limit of normal 5. Absence of major post-operative complications or other clinical conditions that, in the opinion of the investigator, would contraindicate adjuvant chemotherapy 6. Patients should be assessed by Oncology team for suitability and assessment for adjuvant chemotherapy, be able to have post-operative ctDNA sample collected and be randomised by week 8 ± 2 weeks after surgery. 7. ECOG performance status 0- 2 8. Able to give informed consent TRACC Part C Exclusion criteria 1\. History of concurrent and previous malignancy within the last 5 years, with the exception of non- melanomatous skin cancer and carcinoma in situ 2. Any major post-operative complications or other clinical conditions that in the opinion of the investigator would contra-indicate adjuvant chemotherapy 3. Any subject not due to receive adjuvant chemotherapy will not be eligible for Part C of the study 4. Hypersensitivity or contraindication to the drug(s) associated with the planned choice of systemic chemotherapy (CAPOX or single agent capecitabine) as stated in the SmPC for each of the drugs 5. Subjects due to receive 5-Flurouracil (5-FU) based adjuvant chemotherapy (either single agent 5-FU or in combination with oxaliplatin) will not be eligible for Part C of the study \-