Early Detection of Treatment Failure in Metastatic Colorectal Cancer Patients

The general objective of this single-centre, prospective observational cohort study in 100 mCRC-LR patients treated with curative intent along standard of care (SOC), is to obtain real-world data on administered therapies, selected complications, and oncological outcomes, while longitudinally collecting biospecimens to enable correlative research investigating early biological markers of treatment resistance and recurrence. Cryopreservation of sequential blood derivatives, tumor tissue, and stool samples will allow investigation of circulating tumor DNA (ctDNA), T-cell receptor repertoire, somatic cancer mutations, immune and other gene expression, gut microbiome, and soluble factors. The first biological marker that will be investigated in correlative research will be longitudinal measurements of ctDNA targeting 30 oncogenes, 23 axons, and 146 hotspots (Follow It assay, Canexia Health). Additional biological markers will be defined in subsequent amendments to this protocol. The results are expected to provide important insights for the design of future trials investigating ways to personalize therapy, such as to: a) avoid the unnecessary use of neoadjuvant or adjuvant systemic chemotherapy, b) avoid morbid hepatectomies in patients unlikely to benefit, c) test novel preoperative therapies in patients more likely to benefit, and d) modulate the intensity of follow-up.