The most common causes of fecal incontinence are neurological dysfunction or relaxation of the local anal sphincter. In some cases of advanced rectal cancer, excessive tumor growth can enlarge the local intestinal contents, leading to involuntary expulsion of feces. Diagnosis involves further examination using electronic colonoscopy, digital anal examination, and assessment of neurological function. If the cause is related to a neurological disorder, treatment by a neurologist is required. If the cause is relaxation of the anal sphincter, then anal sphincter tightening surgery may be considered. In cases where fecal incontinence is caused by an intestinal tumor, surgery to remove the tumor is recommended, along with radiation or chemotherapy.