Effects of Intravenous Administered Iron in Non-anemic Iron Deficient Patients With Colorectal Cancer

This double-blinded clinical randomized trial with a 1:1 recruitment ratio between placebo and the active group will aim to investigate the effects of intravenously administered iron in non-anemic iron deficient patients on physical capacity, immunological cells and their function prior to surgery. A total of 134 patients with colorectalcancer will be included in the study. Study outline: After initial inclusion the patient will undergo baseline testing with cardiopulmonary exercise test (CPET), then followed by an infusion of a weight dependent dosage of iron(III)isomaltoside or placebo. Then at the closest possible time to the surgery the patient will have drawn bloodwork and be re-tested by (CPET). The patient will be followed after surgery with evaluation of several outcomes including quality of recovery and complications. Further, the effects of the intervention on the patients immune function will be evaluated by two different methods: 1) by changes in neutrophil-to-lymphocyte ratio between baseline and preoperative bloodwork and 2) by evaluation mRNA expression in the tumor specimen by the Nanostring pancancer immune panel