ctDNA-Based Adjuvant Chemotherapy for High-Risk Rectal Cancer

Prior treatment

• Another malignancy in previous 5 years, with the exception of treated carcinoma in situ or skin cancer other than melanoma
• Incomplete primary tumour resection (R1 or R2 resection)
• Neoadjuvant oxaliplatin based systemic treatment, e.g. treated with the RAPIDO regimen consisting of short course radiotherapy followed by 6 cycles of CAPOX or 9 cycles of FOLFOX prior to surgery
• Patients with a clinical complete response, who will not undergo surgery.
• Serious concomitant systemic disorders that would compromise the safety of the patient or his/her ability to complete the study, at the discretion of the investigator
• Current or recent (within 28 days prior to randomisation) treatment with another investigational drug or participation in another study interfering with the primary endpoint.

Other illness

• Metastatic disease
• History of psychiatric disability judged by the investigator to be clinically significant, precluding informed consent or interfering with compliance of the intervention group
• Serious infections (uncontrolled or requiring treatment)

Other

• Contra-indication for fluoropyrimidines or oxaliplatin
• Pregnant and lactating women

• Detectable ctDNA in the postoperative blood sample
• Age ≥ 18 years
• WHO performance score 0-1
• Informed consent for PLCRC with specific consent for additional blood withdrawals and offering of future experimental research
• Informed consent for the REACT trial.
• Histological confirmed rectal cancer; either treated with neoadjuvant (chemo)radiotherapy, and/or clinical/pathological T3/T4 and/or N+ in case no neoadjuvant therapy was administered.
• Eligible to receive treatment with combination adjuvant chemotherapy (CAPOX/FOLFOX) according to the treating physician.
• Mentally competent and able to read and understand Dutch language.