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.