Intravenous iron versus oral iron or observation for gastrointestinal malignancies: a systematic review

Intravenous iron is non-inferior to oral iron regarding cell growth and iron metabolism in colorectal cancer associated with iron-deficiency anaemia

Oral iron promotes intestinal tumourigenesis in animal models. In humans, expression of iron transport proteins are altered in colorectal cancer. This study examined whether the route of iron therapy alters iron transport and tumour growth. Colorectal adenocarcinoma patients with pre-operative iron deficiency anaemia received oral ferrous sulphate (n = 15), or intravenous ferric carboxymaltose (n = 15). Paired (normal and tumour tissues) samples were compared for expression of iron loading, iron transporters, proliferation, apoptosis and Wnt signalling using immunohistochemistry and RT-PCR. Iron loading was increased in tumour and distributed to the stroma in intravenous treatment and to the epithelium in oral treatment. Protein and mRNA expression of proliferation and iron transporters were increased in tumours compared to normal tissues but there were no significant differences between the treatment groups. However, intravenous iron treatment reduced ferritin mRNA levels in tumours and replenished body iron stores. Iron distribution to non-epithelial cells in intravenous iron suggests that iron is less bioavailable to tumour cells. Therefore, intravenous iron may be a better option in the treatment of colorectal cancer patients with iron deficiency anaemia due to its efficiency in replenishing iron levels while its effect on proliferation and iron metabolism is similar to that of oral iron treatment.

Red blood cell transfusions and the survival in patients with cancer undergoing curative surgery: a systematic review and meta-analysis

Allogenic red blood cell transfusions exert a potential detrimental effect on the survival when delivered to cancer patients undergoing surgery with curative intent. We performed a systematic review and meta-analysis to assess the association between perioperative allogenic red blood cell transfusions and risk of death as well as relapse after surgery for localized solid tumors. PubMed, the Cochrane Library, and EMBASE were searched from inception to March 2019 for studies reporting the outcome of patients receiving transfusions during radical surgery for non-metastatic cancer. Risk of death and relapse were pooled to provide an adjusted hazard ratio with a 95% confidence interval [hazard ratio (HR) (95% confidence interval {CI})]. Mortality and relapse associated with perioperative transfusion due to cancer surgery were evaluated among participants (n = 123 studies). Overall, RBC transfusions were associated with an increased risk of death [HR = 1.50 (95% CI 1.42-1.57), p < 0.01] and relapse [HR = 1.36 (95% CI 1.26-1.46), p < 0.01]. The survival was reduced even in cancer at early stages [HR = 1.45 (1.36-1.55), p < 0.01]. In cancer patients undergoing surgery, red blood cell transfusions reduced the survival and increased the risk of relapse. Transfusions based on patients' blood management policy should be performed by applying a more restrictive policy, and the planned preoperative administration of iron, if necessary, should be pursued.