It is possible for cancer to grow on the outer wall of the rectum. Rectal cancer is a common intestinal malignant tumor disease. Patients usually have abdominal distension and pain, change of stool trait, some patients will have anal swelling, and with the development of disease, patients with serious condition will have symptoms such as blood in stool and weight loss. Rectal cancer tissues will keep growing and there will be metastatic spread, resulting in tumors on the outer wall of rectum. Tumors on the outer wall of rectum are usually examined by abdominal enhanced CT and colonoscopy. Patients are recommended to go to regular hospitals for relevant examination to make clear diagnosis and be given surgical resection treatment under the assessment and guidance of professional doctors to achieve ideal treatment effect as far as possible. Rectal cancer is easy to diagnose through rectal finger examination and sigmoidoscopy if its location is low. However, due to its deep location in the pelvis and complex anatomical relationship, the surgery is not easy to complete and the recurrence rate after surgery is high. Therefore, rectal cancer, regardless of whether the tumor tissue grows in the inner or outer wall, should be treated as early as possible and thoroughly once it is found in order to avoid the aggravation of the disease development.