IMPROVE Intervention Trial Implementing Non-invasive Circulating Tumor DNA Analysis to Optimize the Operative and Postoperative Treatment for Patients With Colorectal Cancer

Inclusion Criteria:

• Surgically removed Adenocarcinoma of the colon or rectum
• Pathologically stage I or II disease, and radical resection
• Detectable ctDNA in two weeks postoperative plasma sample
• No indication for adjuvant chemotherapy according to DCCG guidelines (website)
• Age at least 18 years
• ECOG performance status 0-2
• Clinically eligible for adjuvant chemotherapy at investigators decision.
• Adequate bone marrow, liver and renal function allowing systemic chemotherapy (Absolute neutrophil count ≥1.5x109/l and thrombocytes ≥ 100x109/l. Bilirubin ≤ 1.5 xupper normal value and alanine aminotransferase ≤ 3 x upper normal value, andCalculated or measured renal glomerular filtration rate at least 30 mL/min)
• Anticonception for fertile women and for male patients with a fertile partner.Intrauterine device, vasectomy of a female subject's male partner or hormonalcontraceptive are acceptable •
• Written and verbally informed consent

Exclusion Criteria:

• Radiological evidence of distant metastasis, by CT- chest and abdomen
• Incapacity, frailty, disability and comorbidity to a degree that according to theinvestigator is not compatible with combination chemotherapy
• Previous treatment with 5FU or oxaliplatin
• Neuropathy NCI grade > 1
• Other malignant tumor within 5 years except non-melanoma skin cancer or carcinoma insitu cervicis uteri
• Pregnant (positive pregnancy test) or breast feeding women