Many people with cancer undergo surgery for diagnosis or treatment. Fatigue is a problem following surgery, but fatigue from surgery improves with time. It can be made worse, however, when combined with the fatigue caused by other cancer treatments.
Anemia may be a major factor in cancer-related fatigue and quality of life in people with cancer. Anemia may be caused by the cancer, cancer treatment, or may be related to other medical causes.
Fatigue often occurs when the body needs more energy than the amount being supplied from the patient's diet. In people with cancer, 3 major factors may be involved: a change in the body's ability to process food normally, an increased need by the body for energy (due to tumor growth, infection, fever, or problems with breathing), and a decrease in the amount of food eaten (due to lack of appetite, nausea, vomiting, diarrhea, or bowelobstruction).
The moods, beliefs, attitudes, and reactions to stress of people with cancer can also contribute to the development of fatigue. Anxiety and depression are the most common psychologicaldisorders that cause fatigue.
Depression may be a disabling illness that affects approximately 15% to 25% of people who have cancer. When patients experience depression (loss of interest, difficulty concentrating, mental and physical tiredness, and feelings of hopelessness), the fatigue from physical causes can become worse and last longer than usual, even after the physical causes are gone. Anxiety and fear associated with a cancer diagnosis, as well as its impact on a person's physical, mental, social, and financial well-being are sources of emotional stress. Distress from being diagnosed with cancer may be all that is needed to trigger fatigue. Some patients report having more fatigue after cancer treatments than others do. Studies have found that patients who worry about or expect fatigue before, during, or after treatment may be more likely to report having fatigue. (Refer to the PDQ summaries on Depression and Adjustment to Cancer: Anxiety and Distress for more information.)
Mental ability factors
Decreased attention span and difficulty understanding and thinking are often associated with fatigue. Attention problems are common during and after cancer treatment. Attention may be restored by activities that encourage rest. Sleep is also necessary for relieving attention problems but it is not always enough.
Sleep disorders and inactivity
Disrupted sleep, poor sleep habits, less sleep at night, sleeping a lot during the day, or no activity during the day may contribute to cancer-related fatigue. Patients who are less active during the daytime and awaken frequently during the night report higher levels of cancer-related fatigue.
Poor sleep affects people in different ways. For example, the time of day that fatigue is worse may be different. Some patients who have trouble sleeping may feel more fatigue in the morning. Others may have periods of severe fatigue in both the morning and the evening.