Rectal cancer refers to cancer between the dentate line and the junction of rectosigmoid colon, which is one of the most common malignant tumors of the gastrointestinal tract. The location of rectal cancer is low, because of its location deep into the pelvis and complex anatomical relationship, the surgery is not easy to be complete and the recurrence rate after surgery is high. Let’s take a look at what are the early symptoms of rectal cancer? 1. Indigestion: indigestion in early stage of rectal cancer is a very critical thing, and indigestion can cause a series of adverse reactions. For example, patients with dyspepsia will suffer from weight loss, decreased body mass, decreased resistance and immunity, and secondary infections will occur along with these conditions. 2.Blood in stool: Blood in stool is one of the common symptoms of rectal cancer, and more than half of the patients will have blood in stool at the beginning of the disease, but the amount of bleeding at the beginning is usually small and easy to be ignored. The blood is usually attached to the surface of stool, and may be accompanied by abdominal pain and vague pain, and if it is combined with infection, pus and blood stool may appear. 3.Metastasis symptoms: Rectal cancer can metastasize, and the common metastatic sites are liver, lung and bone, which can lead to the corresponding symptoms. When liver metastasis occurs, symptoms such as hepatomegaly, ascites and jaundice may occur; when lung metastasis occurs, symptoms such as cough, hemoptysis and chest pain may occur; when metastasis occurs to the bladder, symptoms such as frequent urination, difficulty in urination and painful urination may occur. 4.Other symptoms: Rectal cancer may also lead to loss of appetite, emaciation, general weakness, anemia, weight loss and other symptoms, and in serious condition, it may be cachectic. 5. Change of stool habit: Generally, after rectal cancer occurs, stool is mainly diluted stool, bloody stool and mucus stool. Blood stool is the most frequent phenomenon in early stage of rectal cancer, and about 90% of patients with early stage of rectal cancer may have the symptom of blood in stool. 6.Change of stool nature: In the early stage of rectal cancer, the cancer will cause irritation to the intestinal mucosa, resulting in the symptoms of thin stool, mucus stool and blood stool. (1) Stool examination: Although the fecal occult blood test is not specific for the diagnosis of this disease, it is a simple and easy method and can provide clues for early diagnosis. (2) rectal examination: most of the rectal masses can be palpated during rectal examination. (3) Colonoscopy: It can clearly observe the whole colon and can take suspicious lesions for pathological examination under direct vision, which is conducive to the detection and confirmation of early and microscopic colon cancer, and is the most important examination means of intestinal cancer. (4) Barium enema: if the lesion is in the upper part of sigmoid colon or higher, barium enema X-ray should be performed. (5) Carcinoembryonic antigen (CEA) determination: carcinoembryonic antigen (CEA) can be detected in the serum of patients with intestinal cancer, but this glycoprotein is not a specific antigen related to intestinal cancer, so serum CEA determination is not specific for the diagnosis of intestinal cancer. (6) Other examinations: endorectal ultrasound scan can clearly show the scope, size, depth and surrounding tissues of rectal masses, and can distinguish the microstructure of each layer of rectal wall, which is a simple examination method and can provide images rapidly, which is helpful for selecting surgical methods and postoperative follow-up.