Fatigue in cancer patients is not related to changes in oxyhaemoglobin dissociation.
ABSTRACT There is only a weak association between the degree of anaemia and severity of fatigue in cancer patients. It has been hypothesised that there may be functional changes in the erythrocytes or haemoglobin of cancer patients and that this may result in fatigue even in the presence of a "normal" or "low normal" haematocrit.
The purpose of the study was to investigate the relationship between oxyhaemoglobin dissociation and fatigue in patients with cancer and to compare oxyhaemoglobin dissociation between cancer patients and healthy controls.
A heterogeneous group of patients with cancer (n = 22) and a control group of healthy subjects without cancer (n = 28) were studied. Subjects completed a fatigue questionnaire [the Functional Assessment of Cancer Therapy Fatigue (FACT-F) scale] and provided 10 ml of blood for analysis. Specimens were analysed to determine the partial pressure of oxygen at which 50% haemoglobin saturation occurred (P50) and were also sent for routine haematological and biochemical analysis.
No differences were found between the oxyhaemoglobin dissociation curves of patients with cancer and controls. There was no significant correlation between fatigue severity and P50 in either patients or controls.
There is no evidence to support the hypothesis that cancer-related fatigue is due to differences in oxyhaemoglobin dissociation.