Diarrhoea

Diarrhoea is an abnormal increase in the amount of fluid in the stool that lasts more than 4 days but less than 2 weeks. It may also be described as an abnormal increase in the amount of fluid in the stool and the passage of more than 3 unformed stools during a 24-hour period. Diarrhoea is considered a long-term problem when it lasts longer than 2 months.

During diarrhoea, food passes quickly through the bowel before your body has a chance to absorb enough vitamins, minerals, and water. This may cause dehydration, which means that your body does not have enough water to work well. Long-term or severe diarrhoea may cause absorption problems either of liquids and of nutrients.

In cancer patients, the most common cause of diarrhoea is cancer treatment (chemotherapy, radiotherapy, bone marrow transplantation or surgery).

  • undergoing surgery to the stomach and/or intestines can affect normal bowel function and cause diarrhoea,
  • some chemotherapy drugs cause diarrhoea by affecting how nutrients are broken down and absorbed in the small bowel,
  • radiotherapy to the abdomen and pelvis can cause inflammation of the bowel and giving problems digesting food, and experience gas, bloating, cramping, and diarrhoea.

Other causes of diarrhoea include infection and antibiotic therapy, stress and anxiety related to being diagnosed with cancer and undergoing cancer treatment. Infection may be caused by viruses, bacteria, fungi or other harmful micro-organisms. Antibiotic therapy can cause inflammation of the lining of the bowel, resulting in diarrhoea that often does not respond to treatment.

More causes of diarrhoea in cancer patients include:

  • the cancer itself,
  • physical reactions to diet or a specific intolerance to certain foods/food constituents,
  • medical problems and diseases other than cancer,
  • the laxative regimen,
  • bowel impaction with leakage of stool around the blockage.

Diarrhoea can occur at any time during cancer treatment. Although diarrhoea occurs less often than constipation, it can be physically and emotionally draining for patients who have cancer. Diarrhoea can cause:

  • changes in eating patterns,
  • fear of eating,
  • a loss of body fluids,
  • chemical imbalances in the blood,
  • impairments in physical function,
  • excessive tiredness,
  • skin problems,
  • a decrease in physical activity,
  • the patient to become house-bound,
  • problems that can be life-threatening in some patients.

These symptoms may last up to 8 to 12 weeks after therapy or may not develop for months or years.

Diarrhoea can often be controlled with appropriate treatments, which may include changes to the diet, medications or surgery.

Source: National Cancer Institute