Targeted Anti-CEA CAR-T Immunotherapy for Advanced Lung Cancer

Inclusion Criteria: \- Participants must meet all of the following criteria to be eligible for enrollment: 1. Age ≥18 years, regardless of gender. 2. Histologically or cytologically confirmed advanced, metastatic, or recurrent lung cancer, including both non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). 3. Disease progression or intolerance after receiving standard therapies (including but not limited to surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy): NSCLC: Disease progression or intolerance after at least second-line standard therapy. SCLC: Disease progression or intolerance after at least first-line standard therapy. 4. For patients with pleural effusion assigned to the intrapleural infusion group, the pleural effusion volume and characteristics must be accurately assessed by imaging (chest CT or X-ray) combined with cytology. Malignant pleural effusion must be confirmed by the presence of tumor cells in pleural fluid cytology. 5. Tumor CEA positivity confirmed by immunohistochemistry (IHC) within 3 months prior to screening, defined as distinct membranous staining with ≥10% positivity. If the tumor sample was assessed more than 3 months prior to screening, a serum CEA level \>10 µg/L is required. 6. At least one measurable lesion according to RECIST 1.1 criteria: Non-nodal lesions: longest diameter ≥10 mm. Lymph node lesions: short axis ≥15 mm. 7. ECOG performance status score of 0 to 2 . 8. Estimated life expectancy of more than 12 weeks. 9. No severe psychiatric disorders. 10. Adequate major organ function unless otherwise specified, defined as follows: Hematology: WBC \> 2.0 × 10⁹/L; Neutrophils \> 1.0 × 10⁹/L; Lymphocytes \> 0.5 × 10⁹/L; Platelets \> 50 × 10⁹/L; Hemoglobin \> 80 g/L. Cardiac function: LVEF ≥ 50% on echocardiogram; no significant abnormalities on ECG. Renal function: Serum creatinine ≤ 2.0 × ULN. Hepatic function: ALT and AST ≤ 3.0 × ULN (≤ 5.0 × ULN if there is hepatic tumor infiltration). Total bilirubin ≤ 2.0 × ULN. Peripheral oxygen saturation \>92% in room air. 11. Eligible for leukapheresis or venous blood collection, with no contraindications to cell collection. 12. Willing to use reliable and effective contraception methods (excluding rhythm method) from informed consent signing until one year after CAR-T cell infusion. 13. Participant or legally authorized representative has voluntarily signed the informed consent form (ICF), indicating understanding of the study objectives and procedures and willingness to participate in the clinical trial. Exclusion Criteria: \- Participants who meet any of the following criteria will be excluded from the study: 1. Clinically symptomatic central nervous system (CNS) metastasis or meningeal metastasis at screening, or other evidence suggesting the presence of uncontrolled CNS or meningeal metastasis, as judged by the investigator. 2. Participation in any other clinical trial within 1 month prior to screening. 3. Vaccination with a live attenuated vaccine within 4 weeks prior to screening. 4. Receipt of the following anti-tumor treatments within 4 weeks prior to screening: chemotherapy, targeted therapy, or any experimental drug treatment within 14 days or at least 5 half-lives (whichever is shorter). 5. Active infection requiring systemic treatment or any uncontrolled infection. 6. Tumor compression of the trachea or major blood vessels, as determined by the investigator to carry a high risk. 7. History of the following cardiac conditions: NYHA Class III or IV congestive heart failure. Myocardial infarction or coronary artery bypass graft (CABG) surgery within 6 months prior to enrollment. Clinically significant ventricular arrhythmias or a history of unexplained syncope (except due to vasovagal or dehydration-related causes). History of severe non-ischemic cardiomyopathy. 8. Active autoimmune disease or any condition requiring long-term immunosuppressive therapy. 9. History of any other untreated malignancy within the past 3 years, except for carcinoma in situ of the cervix or basal cell carcinoma of the skin. 10. Positive for hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) with peripheral blood HBV DNA levels above normal range; positive for hepatitis C antibody with peripheral blood HCV RNA levels above normal range; positive for human immunodeficiency virus (HIV) antibody; positive for syphilis test. 11. Pregnancy or breastfeeding women. 12. Any other condition that the investigator deems unsuitable for participation in the study.