LDRT Combined With Immunochemotherapy for Colorectal Cancer With Liver Metastasis

Inclusion criteria

• Age between18 and 75 years old.
• Histopathological confirmed MSS/pMMR adenocarcinoma of the colon or rectum.
• The clinical baseline stage of rectal cancer assessed by MRI/CT/Transrectal ultrasound was T3-4Nx or TXN1-2.
• Simultaneous liver metastasis confirmed by imaging examination.
• No previous antitumor treatment.
• An Eastern Cooperative Oncology Group (ECOG) performance status ≤1.
• Adequate cardiac function (Left Ventricular Ejection Fractions \> 50%), hepatic function (total serum bilirubin ≤ 1.5 × upper limit of normal, alanine aminotransferase or aspartate aminotransferase ≤ 2.5 × upper limit of normal), renal function (serum creatinine ≤ 1.5 × ULN or glomerular filtration rate \> 60 ml/min, based on Cockcroft-Gault), and hematopoietic function (white blood cells ≥ 4.0 × 109 cells per L, neutrophils ≥ 1.5 × 109 cells per L, hemoglobin ≥ 90 g/L, platelets ≥ 100 × 109 cells per L).
• Sign the informed consent and have good compliance.

Exclusion criteria

• Distant metastasis from other than the liver.
• BMI \< 18.5 kg/m² or weight loss ≥ 10% within the past 6 months (with consideration of the impact of large amounts of pleural and ascitic fluid on body weight).
• Received any of the following treatments: any investigational drug; enrolled in another clinical trial concurrently, unless it is an observational (non-interventional) clinical study; received anti-tumor vaccines or live vaccines.
• Active autoimmune diseases, or a history of autoimmune diseases. A history of liver disease including, but not limited to HBV infection or HBV DNA positive(≥1×10\^4/ml), HCV infection or HCV DNA positive(≥1×10\^3/ml) and liver cirrhosis.
• History of immunodeficiency, including positive HIV test, or other acquired or congenital immunodeficiency diseases, or history of organ transplantation and allogeneic bone marrow transplantation.
• A history of heart disease within 6 months (including congestive heart failure, acute myocardial infarction, severe/unstable angina, coronary artery bypass grafting, cardiac insufficiency ≥ NYHA grade 2 and LVEF\<50%).
• The presence of a clinically detectable second primary malignancy, or history of other malignancies within 5 years excluding adequately treated non-melanoma skin cancer, carcinoma in situ of cervix and superficial bladder tumour (non-invasive tumour, or carcinoma in situ, or T1).
• Pregnant or lactating women.
• The investigator considers that the subject is not suitable to participate in this clinical study due to any clinical or laboratory abnormalities or compliance problems.