• Age ≥18 and ≤75 years old

• Histologically confirmed colorectal adenocarcinoma

• Radiological and/or pathological confirmation of liver metastases, with ≤5 lesions

• Genetic testing and/or immunohistochemistry confirmation of RAS, BRAF wild-type, and pMMR/MSS

• Absence of extrahepatic metastases confirmed by CT, MRI, or PET/CT (if necessary)

• Primary colorectal tumor has been or can be radically resected

• Liver metastatic lesions are resectable (including radiofrequency ablation and SBRT), and postoperative NED (no evidence of disease) is expected. Resectable liver metastases are specifically defined as ① ≤5 metastatic lesions; ② R0 resection can be performed (including radiofrequency ablation and SBRT); ③ Sufficient residual liver volume is expected after resection; ④ At least one hepatic vein can be preserved after resection, with preserved blood flow in and out of the residual liver and preserved bile ducts, and can preserve at least two adjacent liver segments; ⑤ No extrahepatic metastases.

• No prior anti-tumor therapy for liver metastases, except for surgical resection of primary lesions

• Normal hematological function (platelets \>90×109/L; white blood cells \>3×109/L; neutrophils \>1.5×109/L)

• Serum bilirubin ≤1.5 times the upper limit of normal (ULN), transaminases ≤5 times ULN, alkaline phosphatase ≤2.5 ULN, no ascites, normal coagulation function, albumin ≥35g/L

• Liver function classified as Child-Pugh grade A

• Serum creatinine below the upper limit of normal (ULN), or calculated creatinine clearance rate \>50ml/min (using Cockcroft-Gault formula)

• ECOG performance status 0-1

• Expected lifespan \>3 months

• Signed written informed consent

• Willing and able to be followed up until death or end of study or study termination.