Feasibility Study of Adjunctive Bright Light Therapy (BLT) for Amelioration of Fatigue in Chinese Cancer Patients Admitted to a Palliative Care Unit

Fatigue is the most common symptom in palliative care patients who have advanced cancer, ranging from 59% to 77% depends on the assessment method (1). There is limited local data on the prevalence of fatigue in cancer patients. A cross-sectional study by Dr KY Lam in 2009 (unpublished data) found 53% of 55 patients receiving palliative care suffered from severe fatigue. A cross-sectional symptom screening of all the patients in the palliative care ward in Shatin Hospital showed 22 out of 55 (40%) patients reported fatigue (unpublished data).

The fatigue experienced by cancer patients is multi-dimensional. The feeling may be a physical sensation (weakness, tiredness, exhaustion, unable to perform tasks), an affective sensation (low mood, lack of motivation), or a cognitive sensation (lack of concentration, difficulty thinking clearly). This phenomenon is also subject to cultural interpretation therefore there is a need to understand each subject's perception and experience of fatigue within his or her own cultural context (2, 3).

Fatigue is also one of the most under-reported hence under-treated symptoms. Patients may perceive it as a condition to be endured, whereas healthcare workers find it very challenging to assess and treat due to its subjective nature and multidimensional causes. The impairment in self-care capabilities and daily functioning lead to negative effects on desire to continue treatment thus affecting the functional recovery even in patients with a more stable disease status (3-5). The quality of life (QOL) of patients, which is our focus in palliative care service, is heavily reduced (6).

However, evidence-based practice to tackle this distressing problem is still inadequate, and that a one-size fit all approach is unrealistic (7). Various pharmacological options have been examined, but due to limited evidence, no specific drug could be recommended for the treatment of fatigue in palliative care patients in the latest Cochrane review in 2015 (8).

Latest development in management of fatigue includes non-pharmacological approach. Effect size in reducing fatigue in various treatments were summarised in a report by Bower (9). Exercise was more effective than control in reducing fatigue with a mean effect size of -0.27. Psychosocial intervention trials that included fatigue as a primary or secondary outcome have shown reductions in fatigue relative to control, with effective sizes ranging from -0.10 to -0.31. Psychostimulant trials, most of which were conducted among patients with advanced disease and used methylphenidate, suggested that psychostimulants were more effective than placebo in improving fatigue with an effect size of -0.28. Of note, two studies with larger sample size showed no benefit for methylphenidate vs. placebo for improving fatigue (10, 11). The application of non-pharmacological approach in our local patients was even more limited. A pilot study of 26 patients receiving palliative care in Shatin Hospital showed a mean change score of 0.5 (1.862) of improvement in Brief Fatigue Inventory (BFI) Q3 after two weeks of in-patient multidisciplinary care (unpublished data). The estimated effect size of the pilot study was 0.268 (mean change/SD = 0.5/1.863). Overall, these data suggest that non-pharmacological treatments (e.g. exercise, psychoeducation, support program, cognitive-behavioural therapy) have a mild to moderate effect on improving symptom of fatigue.