Neoadjuvant Chemoradiotherapy vs. Chemotherapy Followed by Radical Gastrectomy and Adjuvant Chemotherapy for Advanced Gastric Cancer

Inclusion Criteria:

1. Histologically confirmed gastric cancer with clinical staging determined by endoscopic ultrasound and contrast-enhanced CT or MRI as cT3N2/N3M0, cT4aN+M0, or cT4bNanyM0.
2. Good general condition, with Eastern Cooperative Oncology Group (ECOG) performance status \<2 and no contraindications to surgery.
3. Ambulatory male or female patients aged 18 to 75 years.
4. Sufficient physical fitness and organ function to tolerate major abdominal surgery.
5. Baseline laboratory parameters meeting the following criteria: WBC \> 4.0 × 10⁹/L, ANC \> 1.5 × 10⁹/L, Hb ≥ 100 g/L, PLT ≥ 100 × 10⁹/L, total bilirubin ≤ 1.5 × upper limit of normal (ULN), AST and ALT ≤ 2.5 × ULN, and serum creatinine ≤ 1.0 × ULN.
6. No prior or concurrent diagnosis of other malignancies.
7. Willing and able to comply with study protocol requirements during the trial period.
8. Provided written informed consent prior to screening, with full awareness of the right to withdraw from the study at any time without consequence.
9. Estimated life expectancy of at least 3 months.

Exclusion Criteria:

1. Pregnant or breastfeeding women, or women of childbearing potential not using effective contraception.
2. Receipt of any antitumor therapy prior to surgery.
3. History of or concurrent malignancies other than gastric cancer.
4. Presence of psychiatric disorders, brain metastases, or leptomeningeal metastases.
5. Uncontrolled or severe comorbid conditions or active infections.
6. Decompensated dysfunction of major organs (e.g., cardiac, pulmonary, hepatic, or renal failure).
7. Concurrent participation in another clinical trial.
8. Contraindications to chemotherapy, radiotherapy, or surgery.
9. Active hepatitis B or hepatitis C virus infection.
10. Grade ≥2 peripheral neuropathy (per NCI-CTCAE).
11. Chronic intestinal diseases or short bowel syndrome.
12. Known dihydropyrimidine dehydrogenase (DPD) deficiency.
13. Known hypersensitivity to capecitabine or any of its excipients.
14. Ongoing treatment with sorivudine or related analogs.
15. Deemed unsuitable for participation in this clinical trial by the investigator.