Diarrhea

Diarrhea in cancer patients has diverse etiologies: paraneoplastic syndromes, cancer treatment-induced adverse effects, and infections. Malignant diseases, such as neuroendocrine tumors (VIPoma, gastrinoma, medullary thyroid carcinoma, carcinoid tumors), may cause paraneoplastic syndromes with severe secretory diarrhea. Treatment-induced diarrhea can result from cytotoxic chemotherapy agents such as fluorouracil, capecitabine, irinotecan, paclitaxel, docetaxel, and vinorelbine. Exposure of the gastrointestinal tract to radiation during radiotherapy may cause diarrhea. Surgical resection of bowel can cause a short bowel syndrome. Immune-mediated diarrhea and colitis can result from graft-versus-host disease after allogenic stem cell transplant or colitis after cancer immunotherapy with immune checkpoint inhibitors. In addition to food poisoning and infectious gastroenteritis (including Clostridium difficile), immunocompromised neutropenic cancer patients are at risk for ileitis, typhlitis, and colitis that are potentially life threatening. In addition to supportive clinical management, diagnosis of the cause of diarrhea is very important in order to safely apply the appropriate therapy.