(1) For carcinoma in situ confined to the mucous membrane layer, local excision can be used. (2) Malignant lesion of polyp: when the cancer invades the mucous membrane and submucous layer, but has not yet penetrated the submucous layer, local excision can be used, and the excised specimen should be sent for rapid pathological examination during the operation, and attention should be paid to the periodical rechecking after the operation. (3) Invasive carcinoma: when the carcinoma has penetrated the submucosal layer, the treatment opinions are different. (2) Local excision is feasible if the polyp is cancerous with the following four characteristics: (1) complete excision of the polyp is confirmed by colonoscopy and pathological examination; (2) well-differentiated cancer cells; (3) no cancer at the margin of the incision; (4) no blood vessels and lymphatic vessels are involved. 3.Only polyps that are cancerous with one of the following four items need to undergo colectomy: (1) invasive carcinoma in the head of pedunculated polyps and poorly differentiated; (2) invasion of carcinoma cells into submucosal lymphatic ducts or veins; (3) carcinoma in the margins of the incision; (4) invasive carcinoma in widely based polyps.