fatigue in cancer

Thesis (Ph.D.)--St George's, University of London, 2012.

Includes bibliographical references.

Background: 30-40% of women successfully treated for breast cancer experience chronic fatigue for up to five years after the end of therapy. They experience a number of associated problems including reduced quality of life, lower mood and concentration difficulties. The causes of these problems and the underlying biological pathogenesis of these symptoms are unclear. The primary objective of this research was to identify whether there were differences in objective activity, cognitive function and inflammatory cytokines between fatigued and non-fatigued women post-treatment. Methods: This was a cross-sectional observational study. Women were recruited from a nurse-led follow-up clinic at St George's hospital over a two-and-a-half-year period. These women were categorised on the basis of a semi-structured interview as to whether they met the criteria to be a case of cancer-related fatigue syndrome (CRFS) or acted as a control. All participants completed a set of questionnaires, activity recording, cognitive testing and had blood taken for analysis. Samples were sent to a commercial company for analyte panel testing (88 markers) and were also analysed using proteomic techniques (including mass spectrometry) to identify any differences in plasma proteins between groups. Results: 114 women were recruited; 45 cases and 69 controls. A between group analysis demonstrated statistically significant differences in sleep quality (p=0.02) and daytime activity (p=0.03) on activity recording, and slower processing speed (p=0.009) and impaired verbal memory (p=0.03) on cognitive testing. Blood analysis demonstrated statistically significant differences (p<0.03) with raised inflammatory cytokines on commercial testing (interleukin 18, vascular endothelial growth factor and macrophage inflammatory protein 1) and increased non-specific inflammatory markers on an exploratory proteomic analysis (serum amyloid A and collectin). Conclusions: Statistically significant differences in subjective symptoms, e.g. difficulty concentrating, and linked objective data, e.g. reduced cognitive processing speed, were identified. These differences were associated with evidence of an underlying prolonged inflammatory response (indicated by raised cytokine levels) in the CRFS group. Future work should examine these observed differences prospectively before, during and after treatment.