Fatigue from cancer surgery can last for weeks or months, and may be caused by anxiety as patients prepare for surgery, as well as the pre-admission testing for surgery. Pain after surgery, the effects of anesthesia, sedatives, or analgesics may also cause fatigue. Fatigue from chemotherapy affects most patients, lasting for one to two weeks following treatment then decreasing gradually. Fatigue as a result of radiation therapy affects almost all patients and may worsen during the course of treatment, peaking at 4-6 weeks. Fatigue may lessen after radiation therapy is completed but still continue for weeks or even months.
Many patients undergoing interferon or interleukin therapy also experience fatigue.
Patients may discuss adjusting therapeutic regimens with their doctors to relieve fatigue symptoms. Delaying chemotherapy treatments for 1 or 2 days to attend important life events, or changing the time of their treatment, may be considered. While rest may lessen fatigue associated with a medical illness, it often does not relieve it. Although patients with cancer or other chronic diseases who experience fatigue may need rest or naps during the day, they should recognize that these activities will not eliminate the problem. Excessive bed rest can promote weakness or decreased energy levels and eventually increase fatigue.