Most of the erosions of the sigmoid colon are obtained by colonoscopy and are not considered to be cancerous lesions. Because the sigmoid colon is relatively curved, most of the erosions in this case are due to local impact on the mucosa, resulting in mucosal congestion, edema and damage. This is a relatively common manifestation, mostly due to poor digestion or prolonged constipation and chronic enteritis. Most cancers are characterized by ulcers or atypical hyperplasia with localized mucosal elevation or irregular lesions, most of which are accompanied by positive fecal occult blood and a state of wasting, general weakness or cachexia. Therefore, erosion of the sigmoid colon is only a manifestation of inflammation, not a characteristic of cancer.