Fatigue in patients with advanced cancer : aspects of assessment and measurements

Abstract

Symptoms are very common in patients with advanced cancer, with weakness, fatigue, anorexia, pain, and depression reported as the most common and distressing ones. A core issue in palliative care is to provide relief of symptoms, and to be able to do this satisfactory there is still much to be known about symptom aetiology, prevalence, character and measurement.

In this thesis, focus is on fatigue in patients with advanced cancer. Although fatigue is recognised to affect patients during the whole cancer trajectory, few studies have included and compared individuals at different stages of cancer from early treatment to the end of life. The primary aim was to advance knowledge of fatigue in patients with advanced cancer, by exploring to what extent and in what ways these patients experience fatigue, and to investigate aspects of assessment and measurement of fatigue.

Both quantitative and qualitative methods have been used. Patients with advanced cancer (paper I-IV), patients receiving curative radiotherapy (Paper II, III), patients visiting a medical outpatient clinic (Paper II), healthy individuals (health care staff, Paper II) and registered nurses at a specialized palliative care facility (Paper V), participated in the different studies. In all studies the participants responded to different self-reporting questionnaires, the quantitative data were analysed with descriptive and parametric statistical methods, the qualitative data was explorative using an interpretive descriptive analysis.

The results indicate that patient with advanced cancer experienced fatigue more intensively than did patients earlier in the cancer trajectory, receiving curative cancer therapy. Our results confirm the multidimensionality of fatigue in patients with cancer. At different stages fatigue was most often experienced as a bodily sensation: as an overall feeling of tiredness, tiring easily, not feeling fit or rested, and lack of energy. Mental aspects of fatigue including ability to concentrate, making plans and do things had less of an impact. Being married or cohabiting was found to be related to higher levels of reported fatigue, which contradicts earlier findings. Forty-four percent of the patients with advanced cancer could be classified as depressed, as compared to about 17% of the patients receiving radiotherapy. There is a common agreement that fatigue negatively influences quality of life. It was shown that the relationship between fatigue and emotional functioning, and with quality of life, varies during the palliative care trajectory, and that the relation decreases in the last month of life. This may reflect that other symptoms and aspects of life become more important when patients are getting closer to death. These correlations were strongest for the group of patients who lived between 61 to 120 days.

These findings may be interpreted that the fatigue experience may change at the end of life. We have shown clinical difficulties in making an assessment of quality of life and fatigue with a standardised measurement. This reflects the difficulties to perform these procedures both clinically and for research purposes in palliative care. However, this thesis also demonstrates that fatigue specific instruments are helpful in assessment of fatigue and that patients were able to answer different instruments even very close to death. Future research about fatigue is needed in this group of frail patients comprising physical, psychological, social and existential aspects of fatigue, as well as changes and meaning of fatigue over time.