Constipation, ASCO's curriculum

This section has been reviewed and approved by the PLWC Editorial Board, 05/05

Constipation is the infrequent or difficult passage of stool. About 40% of people receiving palliative care (care given to improve a personís quality of life) and 90% of people taking opioid medications experience constipation. It includes fewer bowel movements, stools that are abnormally hard, discomfort, or a feeling of incomplete rectal emptying.


People with constipation may experience the following symptoms:

  • Pain
  • Swelling in the abdomen
  • Appetite loss

  • Nausea and vomiting

  • Inability to urinate
  • Confusion


Constipation can result when the body begins absorbing more water or begins signaling food to move through the bowel system more slowly. The following cancer-related factors and cancer treatments might also cause constipation:

  • Medications, including antacids; some drugs to treat nausea and vomiting, seizures, depression, diarrhea, or blood pressure; iron supplements; some chemotherapy drugs; and pain medications
  • Eating less food
  • Bowel obstruction
  • Dehydration
  • Immobility (lack of movement)
  • Tumor compression (cancer pressing on the spinal cord)
  • High levels of calcium in the blood
  • Low potassium levels
  • Thyroid problems
  • Diabetes


In planning treatment for constipation, the doctor may do a rectal examination to make sure you don't have a tumor obstructing your rectum and to determine whether there is hard stool in your rectum. The doctor may also ask you about the following:

  • Your bowel habits, before the cancer and now
  • Use of medications that may cause constipation
  • Recent food and fluid intake
  • Other diseases or illnesses


It is very important to treat constipation properly. If it is left untreated, constipation can cause internal damage to the intestine or rectum, dehydration, or bowel obstruction. It can also slow the body's absorption of medications taken by mouth. The following suggestions can help control constipation:

  • Drink more fluids.
  • Take laxatives, given either by mouth or through the rectum.
  • Change the dose or stop medications that cause constipation (under the supervision of your doctor).
  • Eat more fiber or take psyllium or methylcellulose to add fiber to your diet.
  • Increase physical activity, if possible.
  • Have an enema or rectal suppository.

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