Fatigue and Dyspnea

Fatigue and dyspnea are two of the most common symptoms associated with advanced cancer. Fatigue is also commonly associated with cancer treatment and occurs in up to 90% of patients undergoing chemotherapy. Both symptoms have many possible underlying causes. In most patients, the etiology of fatigue or dyspnea is multifactorial, with many contributing interrelated abnormalities. In one study of patients with advanced cancer, fatigue was found to be significantly correlated with the intensity of dyspnea. This chapter will discuss the mechanisms, clinical features, assessment, and management of both of these troublesome and often undertreated symptoms in cancer patients.

Fatigue

Cancer-related fatigue is defined by the National Comprehensive Cancer Network 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.” In cancer patients, fatigue is often severe; has a marked anticipatory component; and results in lack of energy, malaise, lethargy, and diminished mental functioning that profoundly impairs quality of life. It may be present early in the course of the illness, may be exacerbated by treatments, and is present in almost all patients with advanced cancer.

Fatigue is sometimes referred to as asthenia, tiredness, lack of energy, weakness, and exhaustion. Not all of these terms have the same meaning to all patient populations. Moreover, different studies of fatigue and asthenia have looked at different outcomes, ranging from physical performance to the purely subjective sensation.

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