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Every unit of red cells carries iron the body cannot excrete, and someone who has been through leukaemia treatment may have had dozens. It settles in the liver and sometimes the heart. A blood test finds it and an MRI confirms it, and it can be removed either by a chelating drug or by taking blood off once the marrow is working again.
Iron overload appears in the standard list of late effects after blood and marrow transplantation alongside endocrine, cardiovascular and pulmonary disease, and it is one of the items in the international screening and preventive practice recommendations. Its cause is arithmetic rather than biology: the body has no regulated route for excreting iron, each unit of transfused red cells delivers roughly 200 to 250 mg of it, and a person with acute leukaemia who proceeds to transplant may receive many tens of units between diagnosis and engraftment.
Measurement is the straightforward part. Serum ferritin is the screening test, with the caveat that it is an acute phase reactant and rises with inflammation, infection and GvHD, so a high ferritin in the first months after transplant is not by itself evidence of iron loading. Liver iron concentration by MRI, using an R2 or T2-star method, is the confirmatory measurement, and cardiac T2-star measures the compartment that matters most when it is affected.
Treatment after transplant has an advantage over treatment in transfusion-dependent anaemia: once the graft is working and the haemoglobin is normal, iron can be removed by phlebotomy, which costs nothing, has no drug toxicity, and does not depend on adherence to an oral chelator. Chelation with deferasirox or desferrioxamine remains the option where phlebotomy is not tolerated or the haemoglobin will not support it. A multicentre paediatric cohort study of 580 patients with pre-transplant ferritin and 260 with pre-transplant liver iron concentration found that after transplantation 63 per cent had an elevated ferritin and 68 per cent an elevated liver iron concentration, and reported that chelation and phlebotomy were equally effective in reducing post-transplant iron. That study was in children with non-malignant haematological disorders, so it does not transfer directly to adults after transplant for leukaemia, but it is the clearest published comparison of the two removal methods in this setting.
What is not settled, and should not be overstated. The same study found that high pre-transplant ferritin above 2,500 ng/mL was associated with decreased three-year overall survival (adjusted hazard ratio 2.31, 95 per cent CI 1.06 to 5.04), but a sensitivity analysis showed the trend only in patients with severe aplastic anaemia; elevated pre-transplant liver iron concentration above 5 mg Fe per g dry weight was not associated with decreased survival, graft failure, bacteraemia or veno-occlusive disease. The authors wrote that their results challenge the use of liver iron concentration as the gold standard for iron-related risk stratification in transplant. A systematic review of iron overload and transplant outcomes in Diamond-Blackfan anaemia, 42 studies and 443 patients, concluded that the effect could not be determined because exposure definitions were heterogeneous, rated the certainty of evidence very low, and added the sentence that matters here: the absence of a demonstrable association should not be interpreted as evidence that iron overload is safe in the transplant setting.
The grade is moderate: the measurement is reliable, removal works and is recommended in the screening guidance, but the evidence that removing iron after transplant improves survival or organ outcomes in adults is not randomised and is not strong. For a person after transplant the practical question is small and answerable: has my ferritin been checked after the first year, and if it is high, has anyone offered me venesection.
Transfused iron enters the plasma pool bound to transferrin; once transferrin saturates, non-transferrin-bound iron appears and is taken up by hepatocytes, cardiac myocytes and endocrine cells, where it catalyses the production of reactive oxygen species. Removal is possible only by chelation or by physical removal of red cells, because there is no regulated excretory pathway. After engraftment, erythropoiesis can replace the removed red cells, so venesection becomes available in a way it is not during transfusion dependence.
Query for this technology: (TITLE:"Iron overload after transplant" OR ABSTRACT:"Iron overload after transplant" OR TITLE:"transfusional iron overload" OR ABSTRACT:"transfusional iron overload" OR TITLE:"transfusional haemosiderosis after HSCT" OR ABSTRACT:"transfusional haemosiderosis after HSCT" OR TITLE:"post-transplant iron overload" OR ABSTRACT:"post-transplant iron overload") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Iron overload after transplant, not a curated reading list.
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