With high incidence and mortality rate, the effective therapeutic options of colorectal cancer remain limited. Up to 50% of patients with colorectal cancer will develop metastatic disease. Recurrent lesions can be diagnosed and characterized only when tumors have reached a certain volume by present radiologic imaging techniques such as CT and MRI. The exploration of differentiated clinical applications specifically for local recurrence versus distant metastasis remains an unmet need. The aim of this study is to explore methylation, fragmentomic, and cfRNA markers associated with local recurrence and distant metastasis of colorectal cancer by multi-omics approaches. By constructing a predictive model for the localization of post-treatment recurrence and metastasis, this study will compare the accuracy of different technical approaches in predicting the localization of recurrence and metastasis after colorectal cancer treatment.

Inclusion Criteria:

• Age ≥ 18 years, male or female.
• Patients with the following tumor types: primary colorectal cancer, locally recurrent colorectal cancer, colorectal cancer liver metastasis, colorectal cancer lung metastasis, colorectal cancer peritoneal metastasis, colorectal cancer bone metastasis, colorectal cancer multi-organ metastasis, primary liver cancer, primary lung cancer, primary peritoneal cancer, primary bone tumor.
• No prior surgery or anti-tumor treatment at the time of enrollment assessment.
• Subjects voluntarily participate in this study and sign the informed consent form.

Exclusion Criteria:

• Previous history of malignant tumors other than those within the inclusion criteria.
• Pregnant or breastfeeding women.

Patients meeting the following tumor types: primary colorectal cancer, locally recurrent colorectal cancer, colorectal cancer liver metastasis, colorectal cancer lung metastasis, colorectal cancer peritoneal metastasis, colorectal cancer bone metastasis, colorectal cancer multi-organ metastasis, primary liver cancer, primary lung cancer, primary peritoneal cancer, primary bone tumor.