Weert

Patients in the Prospective Dutch ColoRectal Cancer cohort (PLCRC) with non-metastatic colon cancer that gave consent for additional blood withdrawals are enrolled in the observational PLCRC-MEDOCC substudy. In this study, blood is collected before surgery, after surgery and during follow-up. Within PLCRC-MEDOCC, patients with stage II colon cancer that are not considered to have an indication for adjuvant chemotherapy, can be included in the MEDOCC-CrEATE subcohort under the condition that they gave informed consent in PLCRC for biobanking of tissue and for future studies (Trial within Cohorts design). Patients included in MEDOCC-CrEATE will be randomized 1:1 to the (A) ctDNA-based treatment group versus (B) the standard of care group. A total of 1320 patients will be randomized. Patients randomized to the ctDNA-based treatment group will have their post-surgery samples analysed directly after informed consent for MEDOCC-CrEATE. All patients with detectable ctDNA will be offered adjuvant chemotherapy (3 months CAPOX). Patients with undetectable ctDNA will receive routine follow-up at the surgical department. The aim of this Trial within Cohorts study is to investigate how many patients with detectable ctDNA after surgery start with adjuvant chemotherapy.

Researchers are studying patients diagnosed with colorectal cancer, small bowel cancer, and anal cancer to better understand factors that affect treatment outcomes and survival. This study looks beyond tumor stage to explore how biochemical, genetic, environmental, and clinical factors may influence tumor recurrence and patient survival. It aims to address the gap in knowledge caused by most cancer patients not participating in clinical trials, and to validate trial results in a broader patient population. This is a prospective observational cohort study where data is collected from patients starting at their primary diagnosis and continuing until death. After informed consent, researchers gather detailed information on medical history, clinical status, imaging, pathology, tumor characteristics, treatments, hospital stays, side effects, and adverse events. Additional consent allows collection of patient-reported outcomes on quality of life and work ability, as well as biological materials like blood and tumor tissue for research and biobanking. Participants will be closely followed over time with ongoing data collection on treatment effects, clinical outcomes, and patient experiences. The study aims to provide accurate real-world data on various treatments and outcomes and to serve as a resource for future research into prognostic markers, new therapies, molecular studies, and health care policy. The main outcome measured is progression-free survival, tracked for up to 10 years, to better understand long-term treatment impact.