Weert

Researchers are studying patients with non-metastatic stage II colon cancer who are part of the Dutch ColoRectal Cancer cohort PLCRC and who consented to additional blood samples. The study aims to evaluate how many patients with detectable circulating tumor DNA ctDNA after surgery begin adjuvant chemotherapy. This observational and interventional trial includes patients who do not have a standard indication for chemotherapy and involves a randomized design to compare ctDNA-guided treatment with standard care. Patients are randomly assigned to one of two groups the ctDNA-based treatment group or the standard care group. In the ctDNA group, blood samples taken after surgery are analyzed for ctDNA. Those with detectable ctDNA are offered 3 months of adjuvant chemotherapy using CAPOX a combination of fluoropyrimidine and oxaliplatin. Patients without detectable ctDNA receive routine follow-up care. The standard care group receives routine follow-up without knowledge of their ctDNA results. Participants will have blood collected before surgery, after surgery, and during follow-up. Researchers will monitor who starts chemotherapy within 8 to 12 weeks after surgery and will track recurrence rates, disease-free survival, overall survival, time to recurrence, quality of life, and cost-effectiveness over several years. Follow-up assessments occur up to 10 years, allowing detailed long-term evaluation of treatment impact and patient outcomes.

Researchers are investigating how various factors beyond tumor stage, such as biochemical, histopathological, genomic, environmental, and clinical characteristics, affect the outcomes of patients diagnosed with colorectal cancer CRC, small bowel cancer, and anal cancer. This observational study aims to collect detailed information from diagnosis through long-term follow-up to better understand prognosis and treatment effects in both early and late-stage cancers. The study addresses the gap between clinical trial populations and real-world patients by including a broader patient group treated in general practice. Participants will be followed prospectively from their initial diagnosis until death. Data collection includes medical history, clinical parameters, imaging, pathology, tumor details, treatments, hospital stays, interventions, and adverse events. With separate consent, patient-reported quality of life and work ability information will also be gathered. Additionally, biological samples obtained during routine care may be collected for further observational and molecular research. This cohort serves as a platform for evaluating new interventions through a Trials within Cohorts TwiCs design. Throughout up to ten years of follow-up, participants will undergo assessments of progression-free survival, disease-free survival, overall survival, and serious adverse events. Quality of life and work ability are assessed at intervals of 3, 6, 12, 24, 36, and 48 months. This extensive data collection supports a wide range of research aims including prognostic studies, molecular analyses, comparisons of new treatments, and health policy evaluations. The study provides a comprehensive view of treatment outcomes and patient experiences in everyday clinical settings.