Determinants of functional disability in stage IV breast cancer

Abstract

9567 Background: Functional disability degrades cancer patients' quality of life, exhausts caregivers and incurs significant expense yet little is know of the factors that contribute to disablement or whether the impact of these factors differs across functional domains. Better understanding of the influence that symptoms, physical impairments, and disease characteristics exert on disablement is needed in order to develop service delivery models that preserve function. Methods: To identify factors that influence functional performance in community dwelling people with stage IV breast cancer we conducted a cross-sectional study in a tertiary medical center outpatient cancer clinic. A consecutive sample of 163 community-dwelling patients with stage IV breast cancer were administered self- and clinician-rated functional metrics covering multiple domains including overall functioning, mobility, and self care. Self report measures included the Medical Outcomes Study Physical Function Subscale (PF-10) and the Older Americans Resource Study (OARS) Activities of Daily Living (ADL) and Instrumental ADL (IADL) subscales, and clinician report measures included the Karnofsky Performance Scale (KPS) and the Functional Independence Measure (FIM) Total and Mobility scores. Pain and mental health were assessed through administration of the Brief Pain Inventory (BPI) and Mental Health Inventory-17 (MHI-17), respectively. Electronic medical record review provided cancer-related and demographic information. The presence of physical impairments was determined through a comprehensive musculoskeletal and neurological physical examination including the 6 minute walk test. Linear and ordinal logistic regression models were constructed with function metrics as dependent variables. Results: Total number of physical impairments, BPI scores, and the presence of pleural effusions were highly significant in all models (p<0.01). Exertional intolerance and age were associated with PF-10 and OARS-ADL scores (p<0.01), while the presence of a pre-morbid disability was associated compromised mobility. Conclusions: Potentially remediable factors; pain intensity, cumulative impairment burden and pleural effusions, degrade all functional domains in patients with stage IV breast cancer. No significant financial relationships to disclose.