Redefining cancer-related asthenia-fatigue syndrome

Asthenia fatigue syndrome (AFS) is a common symptom perceived by patients with cancer and consists of reported pathologic fatigue, poor endurance, and impaired motor and cognitive function.

The purpose of this study was to examine the relationship between a traditional measure of AFS, visual analogue scale (VAS) fatigue ratings, and a set of more objective functional and physiologic measures (Dietz oncology classification, C-reactive protein, serum albumin, hemoglobin, body mass index [BMI]), Motor Functional Independence Measure (FIM) Score, Cognitive FIM Score. We hypothesized a relationship could suggest the utility of alternative means of assessing and addressing AFS.

We retrospectively examined the records of 131 patients admitted to our facility for inpatient rehabilitation because of disability-causing cancer or its treatment.

Of our sample, 94.7% (124 cases) indicated at least mild fatigue and 97.7% (128 cases) showed abnormal serum albumin, C-reactive protein, hemoglobin, or BMI. We used multiple regression analysis to examine the relationship between VAS fatigue ratings and the aforementioned set of functional and physiologic variables. The regression explained a significant proportion of the variability in VAS fatigue ratings (F = 2.25, df = 7,123, p = 0.03, R = 0.34, R(2) = 0.11). However, only Motor FIM Score accounted for a significant independent contribution to the variability in VAS fatigue ratings.

The data indicate physiologic and functional variables may provide an alternative, objective, and reliable operational definition of AFS. Specifically, using Motor FIM Score, as a surrogate for VAS fatigue ratings may be used to measure the efficacy of AFS treatment.