Study on the Safety and Efficacy of MR-Linac Technique in Patients With Unresectable Locally Advanced Colon Cancer

Inclusion criteria: 1. Patients over 18 years old 2. Patients can remain in a stationary position on the treatment bed for 1-1.5 hours 3. ECOG score 0-1 4. Pathological diagnosis of colon adenocarcinoma, clinical stage cT4N0-2M0 5. Organ function is normal, and the following conditions are required: white blood cell count ≥3.5×10\^9/L; platelet count ≥100×10\^9/L; hemoglobin ≥90g/L. Total bilirubin level ≤1.5× upper limit of normal (ULN); AST and ALT levels ≤2.5 × ULN; endogenous creatinine clearance rate: 56-122ml/min; serum creatinine \<1.0× ULN; serum albumin ≥30g/L. 6. Able to adhere to the study protocol during the research period 7. Signed written informed consent Exclusion Criteria: 1. Patients with dMMR or MSI-H 2. Presence of other types of tumors in addition to colon adenocarcinoma 3. Claustrophobia or inability to undergo MRI or treatment due to the presence of metal implants or other reasons 4. Distant metastasis (M1) 5. Pregnant or lactating women 6. Previous anti-tumor treatment 7. Concurrent use of prohibited drugs for treatment 8. Known history of positive human immunodeficiency virus testing or known acquired immunodeficiency syndrome. 9. Clinically significant (i.e., active) cardiovascular disease: cerebrovascular accident/stroke (\<6 months prior to enrollment), myocardial infarction (\<6 months prior to enrollment), unstable angina pectoris, congestive heart failure (≥New York Heart Association class II) or severe arrhythmia requiring medication treatment 10. Individuals with uncontrolled epilepsy, central nervous system disorders or a history of mental illness, whose clinical severity may hinder signing informed consent or affect patient compliance with oral medication according to the investigator's judgement 11. Organ transplant surgery requiring immunosuppressive therapy 12. Severe, uncontrolled recurrent infections or other severe, uncontrolled comorbidities