Ferric Carboxymaltose Versus Iron Sucrose for Iron Deficiency Anemia After Radical Gastrectomy for Gastric Cancer

Inclusion Criteria: * Age 18 to 75 years, sex male or female, and body weight ≥ 50 kg. * Histopathologically confirmed gastric cancer (TNM stage I-III according to the AJCC 8th edition) and have undergone curative (R0) resection. * Postoperative anemia defined as a hemoglobin (Hb) level \< 100 g/L within 24 hours after surgery (i.e., on postoperative day 1), meeting the diagnostic criteria for postoperative anemia in gastric cancer patients. * Evidence of iron deficiency, as indicated by: * serum ferritin \< 30 μg/L, or * serum ferritin \< 100 μg/L and transferrin saturation (TSAT) \< 20%, confirming iron-deficiency anemia. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2. * Adequate hepatic, renal, and coagulation function, defined as: * ALT and AST ≤ 2.5 × upper limit of normal (ULN), * serum creatinine ≤ 1.5 × ULN, * prothrombin time international normalized ratio (INR) ≤ 1.5. * Estimated life expectancy ≥ 3 months. * Voluntary written informed consent and ability to comply with the trial treatment and follow-up procedures. Exclusion Criteria: Non-iron-deficiency anemia (e.g., hemolytic anemia, thalassemia, megaloblastic anemia, aplastic anemia, tumor-related non-iron-deficiency anemia, etc.) or disorders of hemoglobin synthesis. * Known hypersensitivity to ferric carboxymaltose, iron sucrose injection, or any of their excipients. * Evidence of iron overload (serum ferritin \> 1000 μg/L) or a history of hemochromatosis. * Severe hepatic or renal impairment, defined as: * ALT/AST \> 2.5 × upper limit of normal (ULN), * serum creatinine \> 1.5 × ULN, * or coagulopathy (INR \> 1.5); * or active bleeding (e.g., major postoperative anastomotic hemorrhage, intra-abdominal bleeding, etc.). * Receipt of oral iron, intravenous iron, or erythropoiesis-stimulating agents (ESAs) / erythropoietin (EPO) within the past 3 months prior to screening. * Concurrent other malignancies, severe cardiovascular disease (e.g., heart failure, history of myocardial infarction, severe arrhythmias), uncontrolled infectious disease (e.g., sepsis), or immunodeficiency disorders. * Pregnant or breastfeeding women, or women who plan to become pregnant during the trial period. * Inability to comply with the treatment and follow-up procedures (e.g., due to cognitive impairment, psychiatric disorders), or any other condition that, in the investigator's judgment, would render the participant unsuitable for inclusion in the study.