Fatigue is the most common side effect of cancer treatment.

Cancer treatments such as chemotherapy, radiation therapy, and biologic therapy can cause fatigue in cancer patients. Fatigue is also a common symptom of some cancers. Patients describe fatigue as feeling tired, weak, worn-out, heavy, slow, or that they have no energy or get-up-and-go. Fatigue in cancer patients may be called cancer fatigue, cancer-related fatigue, and cancer treatment-related fatigue.

Fatigue related to cancer is different from fatigue that healthy people feel.

When a healthy person is tired by day-to-day activities, their fatigue can be relieved by sleep and rest. Cancer-related fatigue is different. Cancer patients get tired after less activity than people who do not have cancer. Also, cancer-related fatigue is not completely relieved by sleep and rest and may last for a long time. Fatigue usually decreases after cancer treatment ends, but patients may still feel some fatigue for months or years.

Fatigue can decrease a patient's quality of life.

Fatigue can affect all areas of life by making the patient too tired to take part in daily activities, relationships, social events, and community activities. Patients may miss work or school, spend less time with friends and family, or spend more time sleeping. In some cases, physical fatigue leads to mental fatigue and mood changes. This can make it hard for the patient to pay attention, remember things, and think clearly. Money may become a problem if the patient needs to take leave from a job or stop working completely. Job loss can lead to the loss of health insurance. All these things can lessen the patient's quality of life and self-esteem.

Getting help with fatigue may prevent some of these problems and improve quality of life.