What are gastrointestinal complications during cancer treatment?

Quick Answer
Nausea and vomiting, decreased appetite, mouth sores or inflammation, thrush, diarrhea, constipation, fecal impaction, bowel obstruction, and radiation enteritis.
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Related conditions: Nausea, vomiting, oral mucositis, diarrhea, constipation, impaction, bowel obstruction, radiation enteritis

Definition: Upper gastrointestinal complications of cancer treatment include nausea and vomiting, decreased appetite, mouth sores or inflammation (mucositis), and thrush (yeast infection of the mouth). Lower gastrointestinal complications of cancer treatment include diarrhea, constipation (infrequent passage of dry, hard stools), fecal impaction (accumulation of dry, hardened feces in the rectum or colon), bowel obstruction (blockage), and radiation enteritis (inflammation of the bowel lining due to radiation therapy).

Risk factors: Upper and lower gastrointestinal complications may occur as a result of cancer treatment, such as chemotherapy or other medications given to treat cancer, radiation therapy to the pelvis or abdomen, or surgery. These symptoms also may be the result of an underlying condition, including cancer, central nervous system disorders, bowel obstruction, diverticulitis (outpouchings of the colon), and hernia.

Upper gastrointestinal symptoms may occur as signs or symptoms of esophageal, laryngeal, and other cancers. Lower gastrointestinal symptoms may occur as signs or symptoms of gastric cancer, colon cancer, rectal cancer, bowel cancer, and other cancers. These symptoms also may occur upon the growth or spread of these types of cancer.

Anxiety about cancer or cancer treatment can contribute to the development of gastrointestinal symptoms. In addition, a history of lactose intolerance can increase the patient’s risk of developing lower gastrointestinal complications associated with cancer treatment. Aging and declining health are other contributing factors.

Etiology and the disease process: Chemotherapy and radiation therapy can cause changes in the function of the intestines, including increased or decreased peristalsis (the wavelike contraction of the muscles to propel contents through the digestive tract). An increase in peristalsis can cause stool to move more quickly through the intestines, leading to diarrhea and cramping. A decrease in peristalsis can cause stool to move more slowly through the intestines, leading to constipation, difficulty passing stool, and, in severe cases, fecal impaction, a condition requiring emergency attention. Chemotherapy can also change the normal bacteria in the intestines, causing abdominal pain, cramping, or gas. Fungal, parasitic, or viral pathogens also may contribute to diarrhea.

Partial or complete intestinal or bowel obstructions may occur as the result of a tumor, postoperative adhesion, or a hernia.

Nausea is controlled by part of the central nervous system, and vomiting is a reflex controlled by the brain and stimulated by various triggers, including inflammation in the body. Chemotherapy drugs as well as radiation therapy directed to the gastrointestinal tract, liver, or brain can cause nausea and vomiting. Nausea can also be caused by constipation.

Incidence: Gastrointestinal complications are very common among patients undergoing cancer treatments. The rate of gastrointestinal complications is variable, depending on the type of cancer as well as the extent of the treatment. Side effects may not be the same for each patient or even for patients having the same treatments. In addition, a patient’s side effects may change from one treatment session to the next. The National Cancer Institute reports that 70 to 80 percent of patients undergoing cancer treatment experience nausea and vomiting, and 25 percent of patients experience severe diarrhea.

Symptoms: Gastrointestinal symptoms range from moderate to severe and vary among patients. Symptoms can impede cancer treatment, resulting in a delay, dose reduction, or discontinuation of therapy.

Symptoms of nausea and vomiting may occur during chemotherapy treatment and last a few hours to a few days after treatment. If vomiting occurs for more than twenty-four hours, it is important for patients to notify their physician right away, especially if it is accompanied by abdominal pain or cramping.

Changes in stool frequency, consistency, or volume, or the presence of blood, mucus, or pus in the stool may indicate an underlying disease. If diarrhea occurs more than six times a day or does not resolve within twenty-four hours after taking prescribed antidiarrheal medications, patients should call their physician.

Screening and diagnosis: A thorough review of the patient’s medical history and a physical exam are performed to diagnose gastrointestinal problems. Blood tests can be performed to identify neutropenia, electrolyte imbalances, and renal insufficiency. Stool tests can be performed to identify blood and bacterial, fungal, parasitic, or viral pathogens. Diagnostic tests include upper endoscopy, upper gastrointestinal series (barium swallow), abdominal x-rays, sigmoidoscopy, and colonoscopy.

Treatment and therapy: Symptom management is critical to avoid an interruption in the delivery of cancer treatment. A registered dietitian can provide nutritional therapy to help patients develop eating plans that meet dietary requirements while reducing upper and lower gastrointestinal side effects, helping to make treatment more tolerable. In some cases, antinausea or antidiarrheal medications may be prescribed to help prevent or reduce these troublesome side effects. It is important for patients to ask their physician first before self-treating these side effects, as some over-the-counter remedies could interfere with cancer treatment.

Conservative self-management techniques can be used to manage gastrointestinal complications in many cases. Techniques to manage nausea, vomiting, and diarrhea include the following:

  • Increasing fluid intake to prevent dehydration
  • Eating bland foods in small amounts
  • Following a clear liquid diet of juices and broth until symptoms subside
  • Avoiding spicy, high-fat, and sugary foods
  • Eating small, frequent meals
  • Eating slowly and chewing food completely before swallowing
  • Drinking cool beverages after meals
  • Taking medication with food, unless advised otherwise
  • Eating foods at room temperature

Many of these guidelines are also helpful in managing decreased appetite. Nutritional supplements may be recommended to ensure sufficient caloric and nutrient intake.

Additional tips for managing diarrhea include avoiding high-fiber foods, dairy products, caffeine, and alcoholic beverages and including high-potassium foods, as advised by the doctor.

Techniques for managing abdominal pain include avoiding aspirin and other nonsteroidal anti-inflammatory drugs, unless prescribed; avoiding alcohol and nicotine; and limiting caffeine. Techniques for managing constipation include exercising and increasing consumption of fluids and high-fiber foods.

In addition to these recommendations, relaxation techniques such as deep breathing and guided imagery may help. Patients should follow their physician’s specific guidelines for managing treatment side effects and should call the doctor when symptoms are severe or persist for more than twenty-four hours.

Hospitalization is recommended for patients with dehydration, fever, neutropenia, bowel obstruction, fecal impaction, and nausea, vomiting, or diarrhea that results in the inability to maintain adequate hydration or nutrition. Hospitalization is also recommended for patients with chronic diarrhea that does not resolve within twenty-four hours after taking prescribed antidiarrheal medications. Intravenous fluids can be given, and the patient can be closely monitored in the hospital.

Treatment for a bowel obstruction includes surgical removal, a nasogastric tube to relieve a partial obstruction, or a gastrostomy tube to relieve fluid and air buildup. In some cases, an ileostomy or a colostomy may be recommended.

Prognosis, prevention, and outcomes: Gastrointestinal symptoms can be effectively managed with conservative treatments and medications, and they are generally relieved when cancer treatments are completed. There usually are no long-term effects of gastrointestinal symptoms that are properly managed, according to the American Cancer Society.

Left untreated, chronic gastrointestinal symptoms, particularly diarrhea and vomiting, can cause significant morbidity and mortality due to nutritional deficiencies and fluid and electrolyte imbalances that may result in life-threatening dehydration or impaired kidney function. Constipation can lead to fecal impaction, which can be a life-threatening condition requiring immediate medical attention.

Although cancer treatments can create gastrointestinal complications that are temporarily unpleasant to the patient, the potential side effects should be measured against the cancer-fighting benefits of a particular treatment.


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