Clinical Review

Clinical Assessment and Management of Cancer-Related Fatigue


 

References

From the University of Texas MD Anderson Cancer Center, Houston, TX.

Abstract

  • Objective: To review the evidence on interventions for managing cancer-related fatigue (CRF) and provide evidence-based guidance on approaches to its management.
  • Methods: Nonsystematic review of the literature.
  • Results: Several theories have been proposed to explain the biology of CRF, but there is no single clear mechanism that can be targeted for therapy. The approach to patients begins with screening for fatigue and assessing its intensity, followed by a thorough history and examination to determine whether any reversible medical conditions are contributing to fatigue. Management of underlying medical comorbidities may help some patients. For patients whose fatigue persists, pharmacologic and nonpharmacologic treatment options are available. Pharmacologic options include psychostimulants, such as methylphenidate and modafinil, and corticosteroids. Nonpharmacologic approaches include exercise, cognitive behavior therapy, yoga, acupuncture, and tai chi.
  • Conclusion: We recommend an individualized approach, often with a combination of the available options. Patients need to be evaluated periodically to assess their fatigue, and since cancer-related fatigue affects survivors, long-term follow-up is needed.

Key words: fatigue; cancer; pro-inflammatory cytokines; nonpharmacologic; psychostimulants.

Fatigue is a common distressing effect of cancer [1].It impairs the quality of life of patients undergoing active cancer treatment and of post-treatment survivors. The National Comprehensive Cancer Network (NCCN) defines cancer-related fatigue (CRF) as “a distressing, persistent, subjective sense of physical, emotional and/or cognitive tiredness related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning [2].” Differences between CRF and fatigue reported by individuals without cancer are that CRF is more severe and is not relieved by rest. The prevalence of CRF in cancer patients and survivors is highly variable, ranging between 25% and 99% [2,3]. This variability may be secondary to methods used for screening fatigue and characteristics of the patient groups. In this article, we discuss recognition of CRF and approaches to its management.

Pathophysiology

The specific pathophysiologic mechanism underlying CRF is unknown, making targeted treatment a challenge. The multidimensional and subjective nature of CRF has limited the development of research methodologies to explain this condition. However, research has been done in both human and animal models, and several theories have been proposed to explain the pathophysiology of CRF. While pro-inflammatory cytokines remain the central factor playing a significant role at multiple levels in CRF, there may be a complex interplay of more than 1 mechanism contributing to fatigue in an individual patient.

Central Nervous System Disturbances

The basal ganglia are known to influence motivation. Lack of motivation and drive may cause failure to complete physical and mental tasks, even with preserved cognitive ability and motor function. In a study of melanoma patients receiving interferon, increased activity of the basal ganglia and the cerebellum resulted in higher fatigue scores [4]. Higher levels of cytokines may alter blood flow to the cerebellum and lead to the perception of fatigue. In a study of 12 patients and matched controls, when patients were asked to perform sustained elbow flexion until they perceived exhaustion, CRF patients perceived physical exhaustion sooner than controls. In CRF patients in this study, muscle fatigue measured by electromyogram was less than that in healthy individuals at the time of exhaustion, suggesting the role of the central nervous system in CRF [5]. However, there is not enough evidence at this time to support central nervous system disturbance as the main contributing factor to fatigue in cancer patients.

Pages

Next Article: