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Cancer Health Center

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Fatigue (PDQ®): Supportive care - Patient Information [NCI] - Causes of Fatigue in Cancer Patients

Fatigue in cancer patients may have more than one cause.

Doctors do not know all the reasons cancer patients have fatigue. Many conditions may cause fatigue at the same time.

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General Information About Pancreatic Cancer

This summary provides information about the treatment of exocrine pancreatic cancer. Other PDQ summaries containing information related to cancer in the pancreas include the following: Pancreatic Neuroendocrine Tumors (Islet Cell Tumors) Treatment. Unusual Cancers of Childhood Treatment (pancreatic cancer during childhood). Incidence and Mortality Estimated new cases and deaths from pancreatic cancer in the United States in 2014:[1] New cases: 46,420. Deaths: 39,590...

Read the General Information About Pancreatic Cancer article > >

Fatigue in cancer patients may be caused by the following:

Fatigue is common in people with advanced cancer who are not receiving cancer treatment.

How cancer treatments cause fatigue is not known.

Doctors are trying to better understand how cancer treatments such as surgery, chemotherapy, and radiation therapy cause fatigue. Some studies show that fatigue is caused by:

  • The need for extra energy to repair and heal body tissue damaged by treatment.
  • The build-up of toxic substances that are left in the body after cells are killed by cancer treatment.
  • The effect of biologic therapy on the immune system.
  • Changes in the body's sleep-wake cycle.

When they begin cancer treatment, many patients are already tired from medical tests, surgery, and the emotional stress of coping with the cancer diagnosis. After treatment begins, fatigue may get worse. Patients who are older, have advanced cancer, or receive more than one type of treatment (for example, both chemotherapy and radiation therapy) are more likely to have long-term fatigue.

Different cancer treatments have different effects on a patient's energy level. The type and schedule of treatments can affect the amount of fatigue caused by cancer therapy.

Fatigue caused by chemotherapy

Patients treated with chemotherapy usually feel the most fatigue in the days right after each treatment. Then the fatigue decreases until the next treatment. Fatigue usually increases with each cycle. Some studies have shown that patients have the most severe fatigue about mid-way through all the cycles of chemotherapy. Fatigue decreases after chemotherapy is finished, but patients may not feel back to normal until a month or more after the last treatment. Many patients feel fatigued for months or years after treatment ends.

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