Fatigue is one of the most common side effects of cancer and cancer treatment. There are many factors that contribute to fatigue, such as anemia, poor nutrition, inadequate rest, infection, stress, and others. Likewise, successful treatment of fatigue may require several approaches. For these reasons, it is important to tell your doctor if you have fatigue or if your fatigue is worsening so that you have the best chance of getting a treatment plan that will work for you.
What is fatigue?
Fatigue is a general tiredness or an overwhelming lack of energy. It may be associated with an increasing need for rest, an inability to regain energy with rest, difficulty concentrating, or a disinterest in activities or events.
Compared with symptoms such as nausea or pain, fatigue can be very difficult to identify and discuss. Sensations such as weakness, dizziness, difficulty thinking, and tiredness may be part of the feeling. People sometimes think they are just being lazy or depressed. They may tell themselves, “I can snap out of this if I really try.” Sudden changes in feelings of fatigue may mean there is a serious problem. Slower, gradual development of fatigue may lead to a decreased ability to perform everyday activities. There are no medical tests to measure fatigue; however, fatigue can be treated in many circumstances. Patients experiencing fatigue should report this feeling to their nurse or physician in order to determine whether a treatable cause of fatigue exists and to develop a strategy to reduce the amount of fatigue.
What causes fatigue?
The reasons that patients experience fatigue are many and complex. In fact, fatigue often results from more than one cause and may require the use of many strategies for effective treatment. All of the factors listed below can contribute to fatigue by decreasing the body’s ability to produce energy or by consuming the limited energy produced.
Anemia: Anemia is an inadequate supply of red blood cells, resulting in a decrease in the oxygen-carrying capacity of the blood. A common reason that cancer patients experience anemia is as a side effect of chemotherapy. Anemia is important because it may cause unwanted symptoms, such as fatigue, tiredness or shortness of breath, and may exacerbate or cause other medical problems, such as a heart condition. Fortunately, anemia can be managed. Treatment of anemia may involve the use of red blood cell boosters such as Procrit® (epoetin alfa) or Aranesp® (darbepoetin alfa), a longer-acting form of erythropoietin that allows patients to receive fewer injections. Patients should discuss the risks and benefits of treatment with a red blood cell booster or blood transfusion with their doctor.
Infection: When you have an infection, the body utilizes extra energy to fight the infection, which can contribute to fatigue.
Cancer medications or medical treatments: Many drugs, including those used for the treatment of nausea (antiemetics), pain (analgesics), anxiety (anti-depressants), and other conditions, can cause fatigue as a side effect.
Inadequate nutritional intake: Cancer or cancer treatments may also cause your to lose your appetite, or feel full early (Early satiety). Insufficient intake of calories and vitamins reduces the body’s ability to produce energy and may cause anemia.
Imbalance between rest and activity: Since the 1950’s, space program researchers have studied bed rest as a way of better understanding the effect of a weightless environment on the body. These studies have shown that bed rest or even restriction of activity for 1 or 2 days can decrease the body’s ability to produce energy. Researchers have not identified how much rest is required for recovery versus how much rest contributes to low energy production. However, it appears that extended rest may contribute to fatigue and modest amounts of activity and movement can improve fatigue.
Stress: Pain, anxiety, or depression can cause stress or result in sleep deprivation, causing increased fatigue.
Other medical conditions: Fatigue may be a symptom of other medical problems. Diabetes, heart disease, kidney failure, thyroid dysfunction, and hypercalcemia are common medical problems that can cause fatigue.
What are the symptoms of fatigue?
Compared with symptoms such as nausea or pain, fatigue can be very difficult to identify and discuss. Symptoms may include:
- Difficulty thinking
You may sometimes think that you are just being lazy or depressed. Or, you may tell yourself, “I can snap out of this if I really try.” Symptoms usually start out mild and become progressively worse so that you are unable to perform everyday activities. Sudden changes in feelings or fatigue may mean there is a serious problem.
There are no medical tests to measure fatigue; therefore, it is important that you report any new or worsening symptoms of fatigue to your doctor or nurse.
How can fatigue be managed?
Fatigue has so many different causes and patterns and it may require the use of many strategies for effective treatment. For these reasons, it is important that you discuss your symptoms with your nurse or physician in order to devise an individual plan that will work. While there are no standard medical treatments for fatigue, new tools exist for evaluating and coping with fatigue. The following suggestions may also help you to cope with fatigue and have more energy:
Treat anemia: Anemia is the most common cause of fatigue in cancer patients. It is also very treatable. Learn more about the diagnosis and treatment of Anemia.
Maintain good nutrition: Maintaining good nutritional intake during treatment is especially important because cancer treatments increase the nutritional demands of the body. However, treatments may also cause you to lose your appetite, or feel full early (Early satiety). Work with a dietician or nutritional specialist to ensure that you are getting proper nutrition.
Conserve energy: Try to be realistic about how much energy you have and what you can and can’t do. Only do the things that are most important and ask friends or family for help. It is important to recognize which activities create the most fatigue and also note the frequency, degree, and duration of fatigue so that you can report these to your doctor. If you’re having difficulty managing fatigue, you may wish to ask your nurse or doctor to help family members understand how they can help.
Maintaining normal rest and sleep patterns is important for ensuring quality rest. Plan your daily activities carefully, and schedule rest times between activities throughout your day. Try to rest when you feel the worst and do your activities when you feel better.
Evaluate medications: Review your medications with your doctor, pharmacist, or nurse to ensure that the medications are not causing or contributing to your symptoms.
Exercise: While conserving energy is important, it is equally important to understand that too much rest or inactivity can actually decrease the body’s ability to produce energy and can worsen fatigue. Moderate daily exercise, such as walking, may help to increase your energy level.
Manage stress: Counseling, support services, and medications can all play a role in reducing stress and thereby alleviating fatigue.
 Dunphy FR, Harrison BR, Dunleavy TL, et al. Erythropoietin reduces anemia and transfusions:a randomized trial with or without erythropoietin during chemotherapy. Cancer. 1999;86:1362-1367.
 Glaspy JA, Jadeja J, Justice G. Optimizing the management of anemia in patients with cancer: a randomized, active-controlled study investigating the dosing of darbepoetin alfa (abstract). Proceedings of the American Society of Clinical Oncology 38th annual meeting; May 18-21, 2002. Abstract 1446.
 Kotasek D, Albertson M, Mackey J. Randomized, double-blind, placebo-controlled, dose-finding study of darbepoetin alfa administered once every 3 (Q3W) or 4 (Q4W) weeks in patients with solid tumors [abstract]. Proceedings of the American Society of Clinical Oncology 38th annual meeting; May 18-21, 2002. Abstract 1421.