Sleep disturbance and its association with symptoms of fatigue, anxiety and depression in cancer patients

One-third of cancer patients experience significant sleep disturbance which is commonly associated with other symptoms like fatigue, anxiety and depression. This symptom cluster is highly prevalent (40-80%) across different tumour types and recent work suggests that each symptom maintains the others, further impairing quality of life. Interventions to treat insomnia in cancer patients yield improvements in these other symptoms suggesting shared common pathways. This study explores the association between disturbed sleep and symptoms of fatigue, anxiety and depression in a sample of cancer patients and investigates changes in these symptoms following Cognitive Behaviour Therapy (CBT) for insomnia. Methods: 150 individuals from four cancer groups (breast, prostate, colorectal and gynaecological) participated in the study. All had completed anti-cancer treatment and satisfied the diagnostic criteria for chronic insomnia. The mean age of the sample was 61 years and the mean duration of their insomnia was 53 months. A 2:1 randomisation process in favour of the intervention (100 in CBT and 50 in TAU) was in operation. Results: Baseline assessments indicate significant correlations (P < 0.05) between subjectively assessed sleep quality and physical quality of life (QOL) (r = 0.372), emotional QOL (r = 0.248), functional QOL (r = 0.398), fatigue interference (r = -0.199) and depression (r = -0.236) scores. For the CBT group, post treatment assessments indicated significant correlations between (a) reduction in time awake and (i) reduced depression (r = 0.263), (ii) improved physical QOL (r = -0.215), (iii) improved functional QOL (r = 0.367) and (b) improved sleep quality and (i) reduced fatigue interference (r = 0.198), (ii) reduced depression (r = 0.284), (iii) improved physical QOL (r = -0.309), (iv) improved functional QOL (r = 0.484). Comparisons on the same variables within the TAU group produced no significant associations.