Preoperative intravenous iron and the risk of blood transfusion in colorectal cancer surgery: meta-analysis of randomized clinical trials

 Preoperative anaemia commonly affects 30–60 per cent of the general surgical population, and is associated with an increased risk of postoperative morbidity, prolonged hospital stay, and impaired recovery. Anaemia is more prevalent in colorectal cancer, affecting 60–80 per cent of patients, and as many as 40 per cent of non-anaemic patients with colorectal cancer experience iron deficiency. Iron deficiency and anaemia in patients with colorectal cancer are linked to tumour location and tumour stage. In locally advanced colorectal cancer, intraluminal blood loss and subsequent anaemia can lead to absolute iron deficiency, whereas distant disease, characterized by inflammation and altered catabolism, can cause functional iron deficiency and chronic disease anaemia. Anaemia and iron deficiency are important factors in patients with colorectal cancer owing to their association with increased postoperative complications, impaired recovery, and poorer survival rates. Treating anaemia with allogeneic blood transfusion, however, is associated with adverse patient outcomes as well as increased cancer recurrence rates and higher overall mortality.