Constipation and diarrhea in patients with cancer.

Constipation and diarrhea are both common problems in patients with advanced cancer. They are source of major morbidity and distress. Constipation is, overall, more common that diarrhea. Diarrhea may be severe and, in some cases, associated with life-threatening dehydration and electrolyte abnormalities. Indeed, with some of the newer chemotherapy agents, this is a problem seen with increasing frequency. Oncologists must be familiar with the common causes of constipation and diarrhea in cancer patients and the strategies to evaluate and manage these common and distressing symptoms. Both with constipation and diarrhea, there is a differential diagnosis. In many cases, management can be complex and challenging. Approaches to diagnosis, evaluation, and management are reviewed.