BACKGROUND: Two interventions for fatigue were given during curative cancer 
treatment. The aim of this multicenter randomized controlled trial (RCT) with 
three conditions was to demonstrate the efficacy and to determine the 
contribution of physical activity.
METHODS: Recruited from seven hospitals, 220 patients with various malignancies 
participated in a RCT. The brief nursing intervention (BNI) consisted of two 
1-hour sessions, 3 months apart, given by 12 trained nurses, focusing only on 
physical activity. Cognitive behavior therapy (CBT) consisted of up to ten 
1-hour sessions, within 6 months, provided by two therapists, focusing on 
physical activity and psychosocial elements. The control group received only 
usual care (UC). Assessments took place before and at least 2 months after 
cancer treatment, when patients had recovered from acute fatigue. Fatigue was 
the primary outcome. Efficacy was tested using analyses of covariance. A 
nonparametric bootstrap approach was used to test whether the effect on fatigue 
was mediated by physical activity.
RESULTS: The CBT group was significantly less fatigued than the UC group. 
Between the BNI and the UC groups, no significant difference was found in 
fatigue. The mediation hypothesis was rejected.
DISCUSSION: CBT given during curative cancer treatment proved to be an effective 
intervention to reduce fatigue at least 2 months after cancer treatment. The BNI 
was not effective. Contrary to what was expected, physical activity did not 
mediate the effect of CBT on fatigue. Thus, the reduction in fatigue elicited by 
CBT was realized without a lasting increase in physical activity.