Survivorship: Fatigue, version 1.2014 - Clinical practice guidelines in oncology

NCCN defines cancer-related fatigue as “a distressing, persistent, subjective sense of physical, emotional, and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning.”1 Fatigue is a common symptom in patients with cancer and is nearly universal in those receiving cytotoxic chemotherapy, radiation therapy, bone marrow transplantation, or treatment with biological response modifiers.2–4 According to a survey of 1569 patients with cancer, the symptom is experienced by 80% of individuals who receive chemotherapy and/or radiotherapy.5,6 Cancer survivors report that fatigue continues to be a disruptive symptom after treatment ends,7–14 with studies showing that 17% to 29% of cancer survivors experience persistent fatigue for years after the completion of active therapy.15,16 Persistent cancer-related fatigue affects quality of life, because individuals become too tired to fully participate in the roles and activities that make life meaningful.9,17 Disability-related issues are also relevant for cancer survivors, because obtaining or retaining disability benefits from insurers is often difficult for patients with cancer-related fatigue. Identification and management of fatigue remains an unmet need for many cancer survivors. The specific mechanisms involved in the pathophysiology of cancer-related fatigue are unknown. Proposed mechanisms include proinflammatory cytokines, hypothalamic-pituitary-adrenal axis dysregulation, circadian rhythm desynchronization, skeletal muscle wasting, and genetic dysregulation.18–23 Several studies have focused on the cause of fatigue, especially in cancer survivors with no evidence of active disease, and have suggested that persistent immune system activation and chronic inflammatory processes may be involved.7,24–26 Evidence supporting these mechanisms is limited.