Fatigue is one of the most prevalent and challenging side effects that people with cancer experience. Commonly known as cancer-related fatigue (CRF), the National Comprehensive Cancer Network defines it 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.” CRF affects 50%–90% of patients and can diminish quality of life, lead to functional impairment, and is associated with significant morbidity. Although it improves in many patients the year following treatment, CRF may persist over a much longer period in some.
