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.
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ABSTRACT: Fatigue is one of the most frequent symptoms in palliative care patients, reported in .80% of cancer patients and in up to 99% of patients following radio- or chemotherapy. Fatigue also plays a major role in palliative care for noncancer patients, with large percentages of patients with HIV, multiple sclerosis, chronic obstructive pulmonary disease or heart failure reporting fatigue. This paper presents the position of an expert working group of the European Association for Palliative Care (EAPC), evaluating the available evidence on diagnosis and treatment of fatigue in palliative care patients and providing the basis for future discussions. As the expert group feels that culture and language influence the approach to fatigue in different European countries, a focus was on cultural issues in the assessment and treatment of fatigue in palliative care. As a working definition, fatigue was defined as a subjective feeling of tiredness, weakness or lack of energy. Qualitative differences between fatigue in cancer patients and in healthy controls have been proposed, but these differences seem to be only an expression of the overwhelming intensity of cancer-related fatigue. The pathophysiology of fatigue in palliative care patients is not fully understood. For a systematic approach, primary fatigue, most probably related to high load of proinflammatory cytokines and secondary fatigue from concurrent syndromes and comorbidities may be differentiated. Fatigue is generally recognized as a multidimensional construct, with a physical and cognitive dimension acknowledged by all authors. As fatigue is an inherent word only in the English and French language, but not in other European languages, screening for fatigue should include questions on weakness as a paraphrase for the physical dimension and on tiredness as a paraphrase for the cognitive dimension. Treatment of fatigue should include causal interventions for secondary fatigue and symptomatic treatment with pharmacological and nonpharmacological interventions. Strong evidence has been accumulated that aerobic exercise will reduce fatigue levels in cancer survivors and patients receiving cancer treatment. In the final stage of life, fatigue may provide protection and shielding from suffering for the patient and thus treatment may be detrimental. Identification of the time point, where treatment of fatigue is no longer indicated is important to alleviate distress at the end of life.Palliative Medicine 02/2008; 22(1):13-32. DOI:10.1177/0269216307085183 · 2.85 Impact Factor
Article: Cancer-related fatigue[Show abstract] [Hide abstract]
ABSTRACT: Fatigue is a common symptom in patients with cancer and in disease-free survivors. It has a significant impact on the quality of life. Although subjective fatigue is often related to objective changes in physical functioning or impaired performance status, the two phenomena are not synonymous and need to be distinguished. A number of robust and reliable assessment instruments to measure fatigue severity are now available and criteria for cancer-related fatigue syndrome have been proposed. The underlying mechanisms and pathophysiology of cancer-related fatigue are unclear. Management strategies include the use of psycho-educational interventions, exercise programmes and pharmacological treatments. The best evidence for the effectiveness of drug treatments is for the haematopoietic agents in anaemic patients undergoing chemotherapy and for methylphenidate in an on-treatment population.European Journal of Cancer 06/2008; 44(8):1097-104. DOI:10.1016/j.ejca.2008.02.037 · 4.82 Impact Factor
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ABSTRACT: Fatigue is a common symptom of advanced cancer limiting one's activity and affecting the quality of life. It is a multidimensional symptom complex with subjective and objective components. Hence, its definition and assessment seems arbitrary, incomplete, and elusive. Components of fatigue often merge with other 'disease states' as anemia, depression and so on, compounding difficulty to assess it separately. Fatigue has a high prevalence rate, and lasts longer in chronic diseases like cancer. Its association with treatment modalities like chemotherapy, radiotherapy alongside the primary disease process makes it seemingly ubiquitous in many cases. Systemic manifestation of cancer causes excess demand on body resources on cell repair, uncontrolled growth with metabolite accumulation causing fatigue. Co-morbid conditions of organic and psychological nature causes fatigue. There are many assessment tools for fatigue with different uses and objectives, simple and reproducible tools like Brief Fatigue Inventory, Edmonton Symptom assessment scale seem feasible in everyday practice. Management of fatigue is not straightforward and rewarding. Although treatment of cause appears to be an attractive option, it is not possible in all cases. Therapeutic agents targeting cytokine load is in early stages of study and available results are not favorable. Specific measures aimed at pain relief, prevention/treatment of sepsis, management of depression, avoidance of drugs causing fatigue, restoring the metabolic profile are important. Methyl phenidate, megestrol, and modafinil are some drugs with promising effect to treat fatigue, though confirmatory studies are yet to be established. Non-pharmacological methods are also helpful. Forewarning patients on upcoming fatigue, active regular exercise, and stress management are some of them. Fatigue being a multidimensional entity, single mode of therapy is insufficient. Combined modality tailored to individual patient need and understanding may be the right way to battle this ill-understood symptom. This review article examines the etiopathogenesis and management strategies of fatigue in cancer.Indian Journal of Palliative Care 03/2009; 15(1):19-25. DOI:10.4103/0973-1075.53507