MRD-positive Colorectal Cancer Patients Combined With Personalized Immune Regulation Diagnosis

Inclusion Criteria:

1. They must give informed consent, indicating that they understand the purpose of the study and the procedures required, and are willing to participate in the study.
2. Age 18-80.
3. Pathological examination confirmed colorectal adenocarcinoma.
4. For patients with stage II with high risk factors or stage III with radical surgery, stage II (high risk) colon cancer is defined as (any of):

   a )T4 b)≥ Level 3 c) The clinical manifestations are intestinal obstruction or intestinal perforation d) Histological signs of vascular, lymphatic, or perineural invasion e) Check \< 12 nodes
5. Patients with liver or lung metastases that can be resected in one stage with the primary lesion.
6. There must be sufficient formalin to fix the tumor material in the paraffin embedded (FFPE) block or section tissue (only after sponsor approval), preferably obtained from excision.
7. Patients should meet the following biochemical indicators: total bilirubin ≤2× upper limit of normal (ULN); AST and ALT≤2× upper limit of normal (ULN); Creatinine clearance ≥60 ml/min.
8. Patients should meet the following hematological indicators: neutrophil count ≥1.5×109 /L; Hemoglobin ≥10.0 g/dL; Platelet count ≥100×109 /L.
9. Expected survival ≥ 3 months.
10. Postoperative ctDNA MRD test was positive, routine blood indexes were negative, and imaging was negative.

Exclusion Criteria:

1. Stage I patients and stage II patients without risk factors or MSI-H.
2. Stage IV patients who cannot be surgically resected.
3. Patients with liver, kidney, heart, lung and other dysfunction, unable to tolerate surgery or unable to complete follow-up chemotherapy.
4. Patients who refuse adjuvant therapy such as chemotherapy, are allergic to chemotherapy drugs and have poor compliance.
5. Patients who have received other immunotherapy within 1 month (such as immune checkpoint inhibitor therapy, therapeutic antibody therapy, immune cell therapy, and immune system modulator therapy)
6. Patients with a known past or current malignancy, except where a diagnosis is included, except in the following cases:

   1. Stage 1B or below cervical cancer.
   2. Non-invasive basal cell or squamous cell skin cancer.
   3. Non-invasive superficial bladder cancer.
   4. Prostate cancer with a current PSA level \< 0.1 ng/mL.
   5. Any curable cancer with a complete response (CR) duration of \> 2 years.
7. Patients with hematological and autoimmune diseases.
8. Patients with active hepatitis B or C.
9. Patients affected by drug abuse, clinical or psychological or social factors that make informed consent or the implementation of research.
10. Pregnant and lactating women.
11. Patients with mental illness, senile dementia, etc.