6533b825fe1ef96bd1281ce8

RESEARCH PRODUCT

Erythropoietin to treat anaemia in patients with head and neck cancer

subject

description

based on the improvement of tumour oxygenation through direct effects (oxygen enhancement effect of radiotherapy) and indirect effects (counteraction of the adverse influence of tumour hypoxia on malignant progression), only increases in haemoglobin concentration that result in improvements in tumour oxygenation can be expected to have a favourable effect on prognosis. The haemoglobin concentration range leading to the highest tumour oxygen levels is most probably between 130 and 140 g/L, since this concentration represents an optimum in terms of the counteracting effects of increasing the blood’s oxygen-carrying capacity and rising viscous resistance to flow. At higher haemoglobin concentrations, such as those seen in the erythropoietin-treated group in Henke and colleagues’ study, a substantial rise in the viscous resistance to blood flow within the chaotic tumour microvasculature has to be expected which would in turn lead to a net reduction in oxygen supply. A trend towards lower oxygen partial pressures in patients with head and neck cancer and haemoglobin concentrations above 150 g/L is indeed seen (figure). The apparently negative effect of erythropoietin treatment might, therefore, actually reflect overtreatment. A strong argument to support this possibility can be found in Henke and colleagues’ subgroup analysis, which showed that a significantly poorer outcome with erythropoietin was only seen in cases where the haemoglobin concentration was higher than 110 g/L before the start of treatment.