There is no clinical term for the top 10 precursors of rectal cancer. Most rectal cancer patients do not have typical symptoms in the early stage of development. With the gradual development of the lesion, some patients may experience changes in bowel habits and stool traits, as well as local discomfort such as pain, urgency and heaviness, and systemic symptoms such as fever and fatigue when the tumor breaks down. 1. Changes in bowel habits and stool traits: usually the earliest symptom of rectal cancer, patients mostly show Increased number of bowel movements, diarrhea, constipation, difficulty in defecation, and even bloody stool, mucus stool and pus stool due to the continuous stimulation of rectum by the lesion; 2. Local discomfort: ulcerative tumor continuously stimulates the intestine and causes persistent hidden pain with unclear abdominal positioning. There is a feeling of incomplete defecation when defecating. In addition, there is sacral plexus nerve distribution near the rectum, and when the tumor lesion invades the nerve tissue, it will also cause severe pain in the lower abdomen; 3. Systemic symptoms: If the patient’s condition develops faster or the tumor breaks down, it will also cause systemic symptoms such as fever, fatigue, weakness and mental discomfort; 4. urinary frequency, urinary urgency, urinary pain, difficulty in urination and other urinary system symptoms. Invasion of presacral nerve will cause severe pain in sacrococcygeal area. Some patients may also find masses in the abdomen, and liver metastasis may cause ascites, jaundice, anemia and emaciation.