What causes cancer fatigue?

What causes cancer fatigue?

Cancer treatments, including chemotherapy, radiation therapy, immunotherapy and surgery, can cause fatigue. These treatments can:

• Change how cells work.
• Cause inflammation.
• Make you nauseated and dehydrated.
• Change hormone levels.
• Damage tissues and cells.
• Reduce blood counts, leading to anemia.
• Stimulate the production of cytokines (toxic cell proteins).

The exact reason for cancer fatigue is unknown. Cancer fatigue may be related to both the disease process and treatments, including surgery, chemotherapy, radiation therapy and immunotherapy. Cancer treatments commonly associated with cancer fatigue are:

• Chemotherapy. Any chemotherapy drug may result in fatigue. This may vary from person to person. Some people say it lasts only a couple of days. Others feel the fatigue persists through and beyond the completion of treatment. Drugs such as vincristine, vinblastine, and cisplatin often cause cancer fatigue.
• Radiation therapy. Radiation therapy can cause cumulative fatigue (fatigue that increases over time). This can occur regardless of treatment site. Cancer fatigue usually lasts from 3-4 weeks after treatment stops, but can continue for up to 2-3 months.
• Immunotherapy. Immunotherapy stimulates your immune system to fight cancer. The treatment is also sometimes called biological therapy.
• Bone marrow transplant. This aggressive form of treatment can cause cancer fatigue that lasts up to one year.
• Biologic therapy. Cytokines are natural cell proteins, such as interferons and interleukins, which are normally released by white blood cells in response to infection. These cytokines carry messages that regulate other elements of the immune and endocrine systems. In high amounts, these cytokines can be toxic and lead to persistent fatigue.

Cancer and its treatment can also make you prone to these issues that may contribute to cancer fatigue:

• Anemia. Anemia can result from blood counts that are reduced by treatment. These lowered blood counts reduce the oxygen-carrying ability of the blood (hemoglobin). About 7 in 10 patients experience anemia during chemotherapy.
• Combination therapy. People experiencing more than one treatment at the same time or one after the other may experience more cancer fatigue.
• Tumor-induced "hypermetabolic" state. Tumor cells compete for nutrients, often at the expense of the normal cell's growth and metabolism. Weight loss, decreased appetite and fatigue are common results.
• Decreased nutrition from the side effects of treatments (such as nausea, vomiting, mouth sores, taste changes, heartburn and diarrhea).
• Hypothyroidism. If the thyroid gland is underactive, your metabolism may slow so that your body doesn't burn food fast enough to provide adequate energy. This is a common condition in general but may happen after radiation therapy to the lymph nodes in your neck.
• Medications used to treat side effects such as nausea, dehydration, pain, depression, anxiety and seizures can contribute to cancer fatigue.
• Pain. Research shows that chronic, severe pain increases fatigue.
• Daily routine. Many people try to maintain their normal daily routine and activities during treatments. You may need to modify your routine to conserve energy.
• Stress can worsen feelings of fatigue. This can include any type of stress, from dealing with the disease and the unknowns to worrying about daily accomplishments or worrying about not meeting the expectations of others.
• Depression and fatigue often go hand in hand. It may not be clear which started first. One way to help sort this out is to try to understand how your feelings of depression. Are you depressed all the time? Were you depressed before your cancer diagnosis? Are you preoccupied with feeling worthless and useless? If the answers to these questions are yes, you may need treatment for depression.
• Insomnia. Inability to sleep eight hours a night will cause both mental and physical fatigue.