Purpose: Fatigue is a prevalent, distressing side effect of cancer and cancer treatment which commonly coexists with insomnia. Cognitive behavioral therapy for insomnia (CBT-I) has been shown to improve insomnia in cancer patients, but less is known about its ability to impact fatigue. This work is the analysis for a secondary aim of a four-arm randomized controlled trial (RCT) study assessing the combined and comparative effect of CBT-I and a wakefulness-promoting agent, armodafinil (A), to improve sleep and daytime functioning in cancer survivors. Herein, we examine the effect of CBT-I, with and without A, on fatigue in cancer survivors.
Patients and methods: This study was a four-arm factorial study with CBTI-I (yes/no) versus A (yes/no). It consisted of 96 cancer survivors (average age 56 years; 88 % female; 68 % breast cancer). Fatigue was assessed by the brief fatigue inventory (BFI) and the FACIT-Fatigue scale. The analysis assessed the additive effects of CBT-I and A and possible non-additive effects where the effect of CBT-I changes depending on the presence or absence of A.
Results: Analyses adjusting for baseline differences showed that CBT-I improved fatigue as measured by two separate scales (BFI: P = 0.002, Std. error = 0.32, effect size (ES) = 0.46; FACIT-Fatigue: P < 0.001, Std. error = 1.74, ES = 0.64). Armodafinil alone did not show a statistically significant effect on fatigue levels (all Ps > 0.40) nor did the drug influence the efficacy of CBT-I. Structural equation analysis revealed that reductions in insomnia severity were directly responsible for improving cancer-related fatigue.
Conclusions: CBT-I with and without armodafinil resulted in a clinically and statistically significant reduction of subjective daytime fatigue in cancer survivors with chronic insomnia. Armodafinil did not improve cancer-related fatigue (CRF) and did not change the efficacy of CBT-I. Patients reporting CRF should be screened and, if indicated, treated for insomnia as part of a comprehensive fatigue management program.
Keywords: Armodafinil; CBT-I; Cancer; Cancer-related fatigue.