More on Diarrhea and Cancer

Patient Expert

Diarrhea can be one of the more uncomfortable and embarrassing complications of cancer. We've all had it - enough said. People with cancer are prone to frequent loose or watery stools for many reasons. Chemotherapy, radiation, surgery, bone marrow transplant, and stress can all lead to diarrhea, and certain types of cancer can cause diarrhea directly. In addition to causing social and physical discomfort, uncontrolled diarrhea can be a serious health threat. Though the condition is not typically preventable, there are some ways to find relief.

A number of cancer treatments can lead to diarrhea. Chemotherapeutic agents target fast - growing cells, which is why these medications kill cancer cells. Unfortunately these agents can also damage the intestinal lining, which is filled with fast-growing cells, leading to diarrhea and other complications. In a similar fashion, radiation therapy directed at the abdomen or pelvis can lead to diarrhea by killing the rapidly-growing cells of the bowel lining, and also by damaging the bowel's blood supply. Patients undergoing bone-marrow transplant may experience diarrhea from high dose radiation or chemotherapy prior to cell transfer, and they may also develop a complication called graft-versus-host disease in which the transplanted cells attack the GI tract and other organs. Surgery involving removal of some bowel can lead to diarrhea by altering the intestines' ability to absorb nutrients or fat, leading to an osmotic pull of water into the bowel.

While diarrhea in cancer patients is typically related to treatment, some malignancies can directly cause frequent loose or watery bowel movements. These include colon cancer, neuroendocrine tumors, lymphoma, medullary carcinoma of the thyroid, pancreatic cancer, and bile duct or gallbladder cancer. Some patients with colon cancer present with diarrhea prior to diagnosis. In these cases water is often being secreted behind a tumor that is blocking the intestine. Frequent watery or loose stools result from secretions leaking around the tumor. In contrast, neuroendocrine tumors actually produce hormones that cause diarrhea by stimulating the bowel and bowel secretions.

Though diarrhea is common in cancer patients, uncontrolled diarrhea can cause weight loss, dehydration, and fatigue, and in some cases can be life-threatening. Some helpful measures include avoiding high-fat foods, high-fiber foods, and carbonated beverages.

Drink plenty of fluids

Clear liquids like water, apple juice, clear broth and popsicles, are a great way to maintain hydration.

Eat low-fiber foods

Bananas, rice, applesauce, toast, canned peaches and pears, oatmeal, and  white rice may help.

Get enough potassium

Potassium is an important mineral often lost in diarrhea. Bananas, un-peeled potatoes, and sports drinks are rich in potassium.

Avoid irritating foods

Dairy products, greasy or spicy foods, alcohol, carbonated or caffeinated beverages, and foods high in fat can exacerbate symptoms. Sugar substitutes found in gum and candy can also make symptoms worse.

If dietary measures aren't helpful and diarrhea is severe, your doctor may reduce or hold the responsible treatment. Your physician may also try medications to slow bowel movements, including opioid pain medications, loperamide, bismuth subsalicylate (Pepto-Bismol), aspirin, steroids, and octreotide.

Though diarrhea seems like an embarrassing topic, it must be addressed and it's rare to find a doctor uncomfortable with conversation about bowel movements.   If you are suffering from diarrhea, discuss your symptoms with your medical care team so they can tailor management according to your type of cancer and symptoms.