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There are many causes of fatigue and knowing about them may help you to cope with your fatigue a bit better.
Following surgery|, many people feel tired and need to take things easy for a while. This effect is usually temporary. However, some types of surgery may cause continuing problems with fatigue (for example, if surgery to the stomach leads to problems with absorbing food).
Fatigue caused by chemotherapy| or radiotherapy| usually improves after treatment, but sometimes it can be more of a long-term problem. Many people find their normal levels of energy will return within six months to a year of the treatment ending. However, some people find they still feel tired and have low energy levels a year or so after the treatment has ended. Others still feel tired two years or more after their cancer treatment.
Hormonal therapies| are treatments that can stop or slow the growth of some cancer cells. They either alter the levels of particular hormones in the body or prevent the hormones from being taken up by cancer cells. These are often given for several years. Some but not all hormonal therapies cause fatigue.
Biological therapies| use substances that target the growth of cancer cells. Some but not all biological therapies cause fatigue.
Anaemia is a shortage of haemoglobin in the blood. It is a common cause of fatigue in people with cancer and can be a side effect of cancer treatments.
Haemoglobin, which is found in red blood cells, is the chemical that carries oxygen around the body. As red blood cells circulate in the body, they give energy by carrying oxygen to all the cells of the body.
If the number of red blood cells is low, they can’t carry much haemoglobin around the body, so less oxygen reaches the cells of the body. Haemoglobin is measured in grammes per 100 millilitres (g/dl). The normal range of haemoglobin is 13.5–18 g/dl for a man and 11.5–16.5 g/dl for a woman. If the level of haemoglobin in the blood drops below the normal range, people feel much more tired, and they have less energy.
People who have anaemia may also find that they:
Doctors always keep a check on the levels of blood cells in people who have cancer and cancer treatments.
Cancer treatments may cause anaemia. Chemotherapy reduces the production of red blood cells and is a common cause of anaemia. Radiotherapy can also cause anaemia if it’s given to an area of the body that contains bone marrow. The bone marrow is where red blood cells are produced. Radiotherapy given to the breastbone (sternum), the hip bones or the long bones of the arms and legs is most likely to reduce the production of red blood cells in the bone marrow and cause anaemia.
Anaemia can also occur if a cancer has caused an ulcer (an area that won’t heal) somewhere in the body, such as the stomach or bowel lining. This is because ulcers frequently bleed small amounts.
If you’re having cancer treatment, you may find it helpful to write down your haemoglobin levels in a fatigue diary [PDF 59kb]|. This may help you to see how they affect your everyday life and your level of fatigue. It’s important to let your doctor know if you think your haemoglobin level is making you feel tired. If you are anaemic your doctor may be able to give you treatment, which will make you feel better.
Treatment for anaemia depends on the cause. The main treatment is a blood transfusion|, which involves a drip (transfusion) of red blood cells given directly into the blood stream. It can quickly raise the number of circulating red blood cells.
If you are feeling sick (nausea)|, you may not be getting enough energy from food because you are likely to be eating less. If you’re actually being sick (vomiting), your body doesn’t absorb the food and essential nutrients it needs so this can also make you feel weak and tired. If you have nausea or vomiting, your doctor can prescribe anti-sickness drugs (anti-emetics), which are usually very effective. They should be taken regularly so that the sickness does not come back.
Chemotherapy| can cause changes in appetite| and taste|, which may cause you to eat less. If you are eating less you will also have less energy. If you find that some foods no longer appeal to you, try something different. Your doctor, nurse or hospital dietitian may be able to help.
It can help to get someone else to prepare food for you. Otherwise you may find that you use all your energy to cook the food and then feel too tired to eat it by the time it’s ready. You may also choose to buy ready-made meals from a local shop or place an order with an organisation that delivers ready-made meals to your home. You can also contact your council’s social services department to find out if you qualify for their Meals on Wheels service.
If you don’t feel like eating, you could try ready-made, high-calorie drinks|. These are available from any chemist and some are available on prescription. Unflavoured high-energy powders, which add calories to food without adding bulk, are also available on prescription.
Our eating well| section has more information on coping with eating difficulties| caused by cancer or its treatment.
Many people with cancer don’t have pain, but it can cause fatigue in those who do. Painkillers and other therapies, such as relaxation and acupuncture, can help to relieve pain and so reduce fatigue.
We have more information on controlling cancer pain| which you may find helpful.
Other symptoms such as breathlessness| or fluid-retention are also common causes of fatigue. If you have an infection or fever (high temperature), your body needs more energy and this may lead to fatigue. Treating the different symptoms that are causing your fatigue can often help to relieve it, so let your doctor or nurse know about any symptoms that you have.
We have more information about controlling the symptoms of cancer |which you may find helpful.
Other medical problems, for example diabetes or low thyroid function, that weren’t obvious before the cancer was diagnosed, may come to light during or after cancer treatment. These medical conditions may also make the symptoms of fatigue worse.
Cytokines are proteins produced by the body. They act as chemical messengers and help to regulate a wide variety of functions in the body. Studies have shown that cytokine levels are often raised in people with cancer-related fatigue, and these high levels may actually cause some of the symptoms people experience. Research is currently underway to find out more about the role of cytokines in cancer-related fatigue.
Anxiety|, depression|, stress and tension as well as a poor sleeping pattern can all contribute to fatigue. It’s common for people to have anxiety or depression when they are first diagnosed with cancer. However, these feelings generally get easier to manage as you come to terms with what has happened.
You may find it helpful to discuss how you feel with your partner, another family member or a close friend.
Some people also find it helpful to talk to others at a local support group or join our online community| to meet other people affected by cancer.
If you find that your mood is low and continues to be low most of the time, you may have depression|. If you have depression, your GP will discuss possible treatments with you. They can refer you to a counsellor and can also prescribe medicines to help if necessary.
We have more information about the emotional effects of cancer| which you may find helpful
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Content last reviewed: 1 February 2011
Next planned review: 2013
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
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© Macmillan Cancer Support 2013
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