The life expectancy of rectal cancer patients is related to the stage of the disease. Generally speaking, after treatment, the five-year survival rate ranges from 10% to 90%, and the clinic often doesn’t take the specific life expectancy as a condition for judging the prognosis. Rectal cancer is a malignant tumor caused by gene mutation, bad dietary habits and other factors, and the treatment for the disease is a comprehensive treatment based on surgical resection. After treatment, the prognosis of patients is more related to the stage of the disease, i.e., TNM stage according to the primary tumor, the degree of lymph node metastasis, and whether distant metastasis occurs. It can often be divided into four stages, of which the five-year survival rate of stage I is about 90%; stage II is about 70%; stage III is about 40%; and stage IV is about 10%~15%. In short, the earlier the stage, the better the prognosis and the longer the survival time.