Diarrhea can be one of the most distressing side effects of cancer treatment. Cancer patients are at increased risk of diarrhea because of several factors, including side effects from cancer drugs, radiation, stress, infection, and antibiotics. For appropriate management, the cause of diarrhea should be diligently investigated.
Chemotherapy drugs target rapidly dividing cells in the body, including cancer cells and cells lining the intestinal tract (mucosa). Chemotherapy-induced diarrhea is caused by decreased absorption of fluids due to damage to the intestinal mucosa. However, not all chemotherapy drugs are likely to cause diarrhea. Regimens that contain fluoropyrimidines (like 5-FU and Capecitabine) and irinotecan are more likely to cause diarrhea. Radiation therapy to the abdomen and pelvis can also cause diarrhea by causing damage to the mucosal cells of the gastrointestinal tract.
In recent years, oral targeted cancer drugs, such as tyrosine kinase inhibitors (TKI), have become the backbone of treatment of many different cancers. Though TKIs are generally considered more tolerable than chemotherapy, diarrhea and rash are significant side effects of TKIs.
Patients on immunotherapy medicines like Pembrolizumab and Nivolumab can develop immune-mediated diarrhea, which has a distinct mechanism and treatment approach. Immunotherapy drugs activate the immune system against cancer. However, the body itself can come under attack from its own immune system, causing inflammation in organs like colon, lungs, and skin. Immunotherapy mediated colitis can be life-threatening and may need prompt treatment with drugs that suppress the immune system.
Patients receiving cancer treatment may be at an increased risk of infection. Many viruses, bacteria, parasites, and fungi are known to cause diarrhea. Clostridium difficile (C-diff) is one of the most dreaded causes of health-care associated diarrhea. Cancer patients may be at a particularly high risk of C-diff due to recurrent hospital stays and immunosuppression.
We recommend many evidence-based interventions for patients who experience cancer treatment-induced diarrhea. For mild cases of diarrhea, the BRAT diet, consisting of bananas, rice, applesauce, and toast, helps to reduce the frequency of stools. Patients should maintain intake of clear liquid up to 2-3 liters a day. Other helpful measures include eating small frequent meals and avoiding spicy foods, caffeinated or alcoholic beverages, and foods that are high in fat and fiber. Sometimes drugs like stool softeners and antibiotics, and dairy, may trigger the onset of diarrhea. A dietician can assist patients in choosing the right foods and customize a personalized diet to maintain adequate nutrition and hydration. Some patients may benefit from a clear liquid diet to help with the recovery of bowel function. Fluids rich in salt and sugar, like Gatorade, are preferable to plain water. It is advisable to avoid herbs and supplements like milk thistle, aloe, saw palmetto, Vitamin C, and green tea.
So what happens when non-pharmacologic interventions fail? The supportive care team would generally recommend pharmacologic therapy and supportive care. The “go to” anti-diarrheal meds include Loperamide, Diphenoxylate-Atropine, and Octreotide. Evidence regarding the use of Glutamine and Probiotics is mixed; therefore, at this time, we do not recommend the use of probiotics for the prevention and treatment of diarrhea for all patients. In severe cases, dehydration and electrolyte derangements can occur, requiring IV fluid hydration. We educate patients and caregivers on “alarm symptoms” that indicate the need for prompt evaluation and treatment. Patients experiencing four or more loose bowel movements a day, increased fatigue, dry mouth, low blood pressure, and high pulse are at increased risk for complications from diarrhea.
In our practice, we enlist our patients and families as active partakers in the prevention and management of diarrhea. Our nurses and nurse navigators play a critical role in providing education and support. Although seemingly trivial, simple interventions to prevent and manage diarrhea at home can go a long way in maintaining optimal nutrition, avoiding treatment delays, and optimizing quality of life!
Recent Comments