The purpose of this research is to objectively assess activity behaviours (i.e., physical activity and sedentary behaviour) in patients with malignant pleural effusion. First, we aim to describe the physical activity and sedentary behavior of patients with MPE in Hong Kong. Secondarily, we aim to assess the relationships between activity behaviours and survival, quality of life, and respiratory symptoms e.g. shortness of breath.

The development of a malignant pleural effusion (MPE) can be a consequence of metastatic spread of any cancer, but most commonly lung, breast and gynecological cancers or from primary pleural neoplasms (e.g., mesothelioma). The presence of MPE represents incurable disease and median survival ranges from 3 to 12 months from first presentation. Breathlessness is a common and debilitating symptom reported by this patient group and interventions are aimed at managing symptoms for optimal quality of life.

Breathlessness and other symptoms that result from MPE are likely to limit a person's ability to be physically active. Activity behaviours encompasses physical activity behaviour (i.e., low intensity physical activity and moderate-to-vigorous physical activity) and sedentary behaviour (i.e., sitting or reclining activities low in energy expenditure) accumulated during waking hours. Performance status measures are routinely used in cancer populations and are largely based on self-reported activity behaviors. While performance status is a reliable predictor of survival in patients with MPE, such measures are subjective, broad and significantly, can differ between patients and clinicians. Measures of performance status may fail to detect small, but meaningful changes in activity behaviours. Objective assessment of activity behaviours using accelerometers could provide a more reliable and sensitive method to assess physical activity and sedentary behaviour, particularly in advanced cancer populations. Objective assessment of activity behaviours using accelerometers has been demonstrated to accurately measure physical activity when compared to oxygen consumption. Triaxial accelerometry is considered the most accurate assessment for physical activity in chronic disease populations.

Preliminary research in patients with MPE indicates that patients have very low activity levels. Participants with MPE spent more that 70% of waking hours sedentary (i.e., activities of very low energy expenditure, sitting or lying down). Those patients with MPE with the best performance status and longest survival were significantly more active and less sedentary than those with a poor performance status and limited survival. However, these preliminary results require replication. Further, it is not yet known if activity behaviours are associated with quality of life or symptoms such as dyspnea in this patient population. Evidence from other cancer survivor populations suggests that activity behaviours are linked to quality of life and symptoms. In patients with breast, colorectal, lung and ovarian cancer, those that are more physically active report better quality of life. In patients with lung cancer, symptoms such as breathlessness and fatigue appear to be associated with lower physical activity levels.

Inclusion Criteria:

• Patients with an MPE (i.e. one in which malignant cells are identified in the pleural fluid or pleural biopsy); or a large exudative pleural effusion without other causes in a patient with known disseminated extra-thoracic malignancy

Exclusion Criteria:

• Patients with Age <18 years; pleural infection; pregnant or lactating; inability to consent or comply with the protocol; anticipated pleural drainage procedure within one week subsequent to recruitment.

Patients with an MPE