Safety of Cetuximab and Trifluridin Tipiracil as the Third-line Therapy in the RASwt mCRC

Inclusion Criteria: * 18-75 years old male or female; * Histologically or cytologically confirmed metastatic colon or rectal adenocarcinoma; excluding appendiceal cancer and anal canal cancer; * Previously received second-line treatment, at least 2 standard chemotherapy regimens(including fluorouracil, capecitabine, irinotecan, oxaliplatin, raltitrexed and anti-VEGF, anti-EGFR, etc.), if already accepted anti-EGFR treatment achieved at least PR or above; * ECOG PS 0-1; * At least one measurable lesion by CT or MRI (according to RECIST 1.1 criteria, the longest diameter of tumor lesion CT/MRI scan ≥ 10 mm, lymph node lesion CT/MRI scan shortest diameter ≥ 15 mm); * RAS gene mutation detection results are wild-type. The test sample can be the primary tumor or metastasis sample; * Can receive oral drug treatment; * Normal function of major organs, meeting the following criteria within 14 days before the start of treatment: 1. neutrophil count ≥ 1.5 × 10\*9/L; 2. Platelet count ≥ 75 × 10\*9/L; 3. Hemoglobin ≥ 9.0 g/dL; 4. AST ≤ 2.5 × UNL (upper limit of normal) (if liver metastasis AST ≤ 5 × UNL); 5. ALT ≤ 2.5 × UNL (if liver metastasis AST ≤ 5 × UNL); g.Creatinine clearance (calculated according to Cockcroft and Gault formula) \> 60 mL/min or serum creatinine ≤ 1.5 × UNL; * Expected survival time \> 3 months (90 days); * Women of childbearing potential must have used reliable contraception and had a negative pregnancy test within 7 days prior to enrollment and be willing to use an appropriate method of contraception during the trial and for 6 months after the last dose of trial drug. Males must agree to use an adequate method of contraception or have been surgically sterilized during the trial and for 6 months after the last dose of trial drug; * The patients voluntarily participated in this study and signed the informed consent form, with good compliance and cooperation in the follow-up. Exclusion Criteria: * Previously treated with regorafenib, fruquintinib, TAS-102; * Participated in another drug clinical trial in the past 4 weeks, or received systemic chemotherapy, radiotherapy or biological therapy in the past 4 weeks; * Known brain metastases or strongly suspected brain metastases; * Patients with known BARF mutations should be excluded; * Synchronous cancer or metachronous cancer with disease-free survival ≥ 5 years (except colorectal cancer), excluding mucosal cancer (esophageal cancer, gastric cancer, cervical cancer, non-melanoma skin cancer, bladder cancer, etc.) that has been cured or may be cured by local resection; * Factors that significantly affect the absorption of oral drugs, such as inability to swallow, chronic diarrhea and gastric intestinal obstruction; ucontrolled Crohn's disease or ulcerative colitis; * Serosal effusion (including pleural effusion, ascites, pericardial effusion) with clinical symptoms and requiring symptomatic treatment; * Pregnant or lactating women; patients of childbearing potential are unwilling or unable to take effective contraceptive measures; * Known to be allergic to the study drug, study drug class and its ingredients; * Conditions requiring systemic steroid treatment (except topical steroid and cetuximab pretreatment); * History of interstitial lung disease (interstitial pneumonia, pulmonary fibrosis, etc.) or CT findings of interstitial lung disease; * Active local or systemic infection requiring treatment; * Cardiac function classification (NYHA classification) ≥ Grade III or severe heart disease; * Known history of human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) or active hepatitis B, C; * Toxicity not recovered (CTCAE \> grade 1) or not completely recovered from previous anticancer surgery; * Patients judged by the Investigator as unsuitable for this study.