Rectal cancer may not have any symptoms in the early stages. Some patients may experience symptoms such as changes in bowel habits, blood in the stool, and abdominal pain. Many rectal cancers do not cause any symptoms but are detected during routine screening tests. You need to be alerted to the presence of rectal cancer if you experience any of the following symptoms: changes in bowel habits, such as constipation or diarrhea, narrowing of the shape of the stool, or blood in the stool. Stomach pain and/or cramping, or painful bowel movements, may also be early symptoms of rectal cancer. There may also be pelvic or lower abdominal pain, unexplained weight loss, or feeling tired all the time. Patients should pay special attention when the above symptoms occur and are advised to go to the anorectal department of the hospital for timely examination to avoid delay. It is recommended that people after the age of 45 should do rectal cancer screening once a year for early detection and early treatment.