INNV-59. Neutral Effect of Post-Resection Iron Therapy on Glioblastoma Outcomes: A Retrospective Cohort Study Using Target-Trial Emulation Framework

Abstract INTRODUCTION Anemia develops in more than half of glioblastoma (GBM) patients during the postoperative and early adjuvant period, driven by surgical blood loss, bone-marrow suppression, and cancer-related inflammation. Iron supplementation is widely used to correct postoperative anemia in other surgical populations, and modern intravenous preparations allow rapid repletion even when inflammation limits oral absorption. However, there is little high-quality evidence showing that proactive iron therapy improves clinical outcomes in GBM patients. METHODS This study aims to evaluate whether timely iron supplementation in patients who develop anemia within 60 days after GBM surgery is associated with improved overall survival compared with no iron treatment. We conducted a retrospective cohort study using the TriNetX U.S. Collaborative Network, a multicenter database encompassing 71 healthcare organizations across the United States. We identified adult patients with GBM who underwent surgery and were diagnosed within 60 days postoperatively with iron deficiency anemia, acute posthemorrhagic anemia, neoplasm-related anemia, or moderate-to-severe anemia (hemoglobin < 8 g/dL). Patients were classified into two groups based on whether or not they received iron supplementation. Propensity score matching (1:1) was performed to ensure balanced baseline characteristics between groups. RESULTS A total of 51 patients who received iron supplementation and 396 who did not were included. After 1:1 propensity score matching, baseline characteristics were well balanced (standardized mean differences < 0.1; mean age: 62.3 ± 15 vs. 63.0 ± 14.9). During 1-year follow-up, iron supplementation was associated with a non-significant increase in all-cause mortality (hazard ratio [HR] 1.80; 95% CI, 0.92–3.52). Similar trends were observed at 3 and 5 years (HR 1.68 [0.94–2.98] and HR 1.60 [0.91–2.82], respectively). CONCLUSION Iron supplementation within 60 days after GBM surgery showed no significant impact on overall survival. Further studies incorporating anemia severity and treatment timing are warranted.