Preoperative intravenous iron treatment – a cohort study on colorectal cancer recurrence

Background: Intravenous (i.v.) iron treatment has been speculated to increase the malignant potential of colorectal malignancies but also to enhance the immune systems potential to fight the invasive tumor. Clinical data however is very limited. We investigate if preoperative i.v. iron treatment is associated with colorectal cancer (CRC) recurrence. Methods: Retrospective cohort study on surgical CRC patients with iron deficiency anemia (1st March 2013 - 31st December 2019). Patients were grouped based on whether they had received preoperative treatment with i.v. iron. Local data was combined with data from the National Danish Health registries to identify recurrences, death, and emigration. Survival analysis, including Kaplan-Meyer curves and multivariate competing risk analysis adjusting for sex, age, ASA-group, tumor stage, surgical radicality, and miss match repair status was performed. Results: Of 1228 patients, 125 were available for analysis. 89 patients had received preoperative i.v. iron and 36 had not. The two groups were comparable on baseline and surgical characteristics. Median follow-up times were 4.74 in iron treated patients and 5 years in patients not receiving iron treatment. Five-year rate of non-recurrence was 85 % (0.74–0.91) in the i.v. iron treated group vs. 82 % (0.64–0.91) in the control group, non-significant difference. Multivariate survival analysis did not find iron treatment to be associated with recurrence rates (Hazard Ratio 0.88 (95 % ci; 0.31–2.51). Conclusion: No association between preoperative i.v. iron treatment and the five-year cancer recurrence rate in iron deficient anemic CRC patients was found