The effect of anaemia on the fraction of hypoxic cells in an experimental tumour

Retrospective clinical studies have suggested that tumours in anaemic patients are more difficult to control by radiotherapy than those in patients with normal haemoglobin levels. To investigate this effect, a transplantable tumour in mice has been irradiated when the host animal either was anaemic or had a normal haemoglobin level. The results indicate that the fraction of hypoxic cells in the tumours in anaemic mice is twice as large as that in tumours in normal mice. The significance of this difference is discussed in terms of possible improvements in local tumour control.