Mike: Hello, I'm Mike Clarke, podcast editor for the Cochrane Library. Cochrane has produced several systematic reviews of interventions that might help people suffering from anaemia. In this podcast, Claire Iannizzi talks with lead author Anne Adams, both from the University Hospital Cologne in Germany, about a review of intravenous, oral or no iron in combination with erythropoiesis-stimulating agents for cancer patients with anaemia, which was published for the first time in June 2022.

Claire: Hello Anne, first of all, what is anaemia and why do people with cancer develop it?

Anne: Hello Claire. People develop anaemia when their levels of red blood cells are too low, which is a problem because these cells contain a protein called haemoglobin that carries oxygen around the body. A lack of oxygen in the body makes people tired, and they may be at greater risk of infections. People with cancer might be affected by anaemia because the cancer causes inflammation and hinders the production of red blood cells. 

Claire: So, is there a recommended treatment for people with cancer who develop anaemia?

Anne: People suffering from anaemia may need blood transfusions, but treatment with iron supplements and medicines that stimulate the production of red blood cells in bone marrow, called erythropoiesis-stimulating agents or ESAs for short, may reduce the need for transfusions. Our review looks at the effects of these.

Claire: Could you tell us a little more about why it's important to do this review and why you conducted a network meta-analysis?

Anne: We wanted to find out which are the most effective treatments or treatment combinations for anaemia in people with cancer and whether they cause any unwanted effects. By using a network meta-analysis that brings together the results of many studies, we were hoping to compare all treatment options against each other and to rank them in order of their effectiveness and unwanted effects.

Claire: What studies did you want to include and were there enough of them?

Anne: We searched for studies comparing intravenous, oral or no iron with or without ESAs for the prevention or treatment of anaemia resulting from chemotherapy, radiotherapy, combination therapy or the underlying malignancy in people with cancer. In total, we found 96 relevant studies including approximately 25,000 people of different ages and receiving a mix of anti-cancer treatments or no treatment for a variety of types of cancer. Of these, 92 studies reported data that we could use in the review, allowing us to compare 12 different treatment options in total.

Claire: And what did you find?

Anne: Our review shows that treatment with ESA, either alone or in combination with iron, probably increases levels of red blood cells and reduces the need for transfusions when compared with no treatment. However, we cannot rule out an increased risk of mortality with ESA in combination with iron, which also seemed to lead to increased risk of harm caused by the formation of clots in the blood vessels.

Claire: Overall, how certain are you about these findings?

Anne: Overall, we're moderately confident in the evidence, but we sometimes found very different results for the same treatments. This means that a particular treatment might be good for some patients but bad for others. So, our confidence in the results for individual treatments is limited and we could not reach firm conclusions or provide a ranking of all treatment options for cancer patients with anaemia.

Claire: Finally, what's your take-home message?

Anne: Our key message is that when considering ESA with or without iron for the prevention or treatment of anaemia, one has to balance between effectiveness and unwanted effects. Our network meta-analysis suggests that treatment with ESA in combination with iron probably decreases the need for transfusions and increases levels of red blood cells, but may also increase mortality and unwanted effects. Since a treatment ranking of all included treatment options was not possible, we need more studies that compare these treatments directly against each other to refine our findings.

Claire: Thanks Anne. If people would like to read your review, how can they get hold of it?

Anne: Thanks Claire. The review's available online. If they go to Cochrane Library dot com and type 'ESA' in the search box, they'll see a link to the review near the top of the list.