This observational study aims to evaluate the predictive performance of various omics-based methods for detecting minimal residual disease (MRD) in stage III colorectal cancer. The study involves the collection of blood samples from patients who have accepted surgery for colorectal cancer. Blood samples will be analyzed using both tumor-informed and tumor-agnostic approaches to detect circulating tumor DNA (ctDNA). The study will compare the sensitivity of these methods and assess their correlation with recurrence risk. The findings aim to inform the development of optimal MRD detection strategies, ultimately providing a robust molecular basis for personalized treatment decisions.

Inclusion Criteria:

• Age ≥ 18 years.
• Histologically confirmed colorectal cancer.
• Preoperatively assessed as stage III according to the 8th edition UICC/AJCC staging system.
• Deemed eligible for radical resection upon investigator assessment.
• No prior anti-tumor therapy received.
• ECOG PS score 0-1.
• Willing and able to provide signed informed consent for participation in the study.

Exclusion Criteria:

• Has a history of other malignant tumors.
• Pregnant and lactating women.
• Presence of any concurrent medical or psychiatric condition, as assessed by the investigator, that may interfere with protocol compliance, study follow-up, or affect short-term survival.

A total of 229 patients newly diagnosed with stage III colorectal cancer.