Cancer-Related Fatigue Is Associated With Objective Measures of Physical Function in Survivors of Cancer

Abstract

Purpose: Cancer-related fatigue (CRF) is a common and limiting symptom reported by survivors of cancer and may have a negative impact on functional activities. The purpose of this study was to investigate the relationships between CRF and objective measures of physical function in survivors. Methods: A retrospective analysis was performed on 428 survivors initiating a clinical exercise oncology program. A physical assessment was performed prior to program start and included a six-minute walk test (6MWT), handgrip strength assessment, and a 10 m walk test to measure both usual and fast gait speed. CRF was measured with the Functional Assessment of Chronic Illness Therapy Fatigue scale (FACIT-Fatigue), a commonly used 13-item questionnaire, with scores ranging from 0–52. Lower scores indicate greater CRF. Participant demographics, cancer diagnosis, and treatment information were self-reported at program start. Four multiple linear regression analyses were performed, with 6MWT, handgrip strength, usual gait speed, and fast gait speed as the dependent variables. In each model, FACIT-Fatigue was entered as a predictor and covariates were age, gender, cancer diagnosis, and cancer treatment (currently receiving chemotherapy or radiation or not). Results: Participants were on average 55.2 (SD = 14.1) years old, majority women (64%) and breast cancer survivors (30.5%). Approximately half were currently receiving cancer treatment (48%). The means (SD) of measures of physical function were: 6MWT = 582 (120) m; grip strength = 32.7 (10.5) kg; usual gait speed = 1.36 (0.25) m/s; and fast gait speed = 1.9 (0.38) m/s. The mean (SD) FACIT-Fatigue score was 33.7 (10.8). All regression models were significant (P < 0.01). FACIT-Fatigue was significantly associated with 6MWT (Î2 = 3.39, P < 0.01), handgrip strength (Î2 = 0.13, P < 0.01), usual gait speed (Î2 = 0.005, P < 0.01), and fast gait speed (Î2 = 0.009, P < 0.01). Conclusions: Findings demonstrated that higher CRF was significantly associated with reduced performance on objective measures of physical function, providing insight on how CRF may contribute to limitations of functional day-to-day activities. Future studies should investigate whether reductions in CRF mediate the improvements in physical function seen after participation in exercise programs.