1.The clinical manifestation of left hemicolectomy is mainly acute and chronic intestinal obstruction; right hemicolectomy is not easy to occur intestinal obstruction. Explanation: the intestinal cavity of the left hemicolectomy is thin, the stool in the intestine becomes dry and hard due to water absorption, and most of the left hemicolectomy is infiltrative type, which often causes annular stenosis, so the clinical manifestation of the left hemicolectomy is mainly acute and chronic intestinal obstruction; the intestinal cavity of the right hemicolectomy is larger, the intestinal wall is thin and easy to expand, the physiological function is to absorb water, electrolytes and some glucose, and the intestinal contents are mostly liquid or semi-liquid, so the right hemicolectomy is not easy to occur 2. Left hemicolectomy is less likely to break and bleed (even if it bleeds, the amount is generally less, and the blood is mixed with stool, with dark red or bright red color, and heavy bleeding is rare); right hemicolectomy is prone to ulceration and bleeding. Explanation: the volume of left hemicolectomized colon cancer mass is generally smaller, and the blood supply of left hemicolectomized colon is not as rich as that of right hemicolectomized colon, so it is less likely to ulcerate and bleed; the right hemicolectomized colon is rich in blood supply, the colon cancer tumor grows fast, the tumor is large, and because the cancer invades blood vessels, central ischemic necrosis often occurs, resulting in ulceration and bleeding, which is manifested as occult blood in stool when there is not much bleeding in early stage, and later bleeding gradually increases and the stool is dark red or sauce color. 3.Left colon cancer is not easy to find the mass, while right colon cancer can often palpate the mass. Explanation: Left hemicolectomized colon cancer mass is small in volume, so it is not easy to find the mass; right hemicolectomized colon cancer mass grows fast and is large, so 80% of patients can find the mass in the right abdomen, and the ileocecal mass is especially common. 4. Left hemicolectomized colon cancer rarely has anemia, emaciation, cachexia and other phenomena; right hemicolectomized colon cancer mostly has the above mentioned manifestations. Explanation: Left hemicolectomized colon cancer is smaller in size, less collapse and bleeding, and generally no toxin absorption, so anemia, emaciation, cachexia and other phenomena are rare; right hemicolectomized colon cancer is more likely to have central necrosis, collapse and bleeding, and it is easy to have secondary infection and significant toxemia symptoms, which are often manifested clinically as emaciation, weakness, loss of appetite, fever and other systemic toxic symptoms. 5.Left hemi-colon cancer is easy to metastasize to left hemi-liver; right hemi-colon cancer is easy to metastasize to right hemi-liver. Explanation: The left hemicolectomy occurs in the post-embryonic protointestine, blood is supplied by the inferior mesenteric artery, and venous blood enters the splenic vein through the inferior mesenteric vein, and then goes to the left half of the liver through the portal vein, so the left hemicolectomy is more likely to metastasize to the left half of the liver. Therefore, the left hemicolectomy is more prone to metastasis to the left hemicolectomy, while the right hemicolectomy occurs in the embryonic mesocolon, blood is supplied by the superior mesenteric artery, and venous blood flows back to the right hemicolectomy mainly through the superior mesenteric vein. 6.The early diagnosis rate of left hemicolectomy cancer is higher; the early diagnosis of right hemicolectomy cancer is easy to be misdiagnosed. Explanation: Left hemicolectomy cancer can show stool change and obstruction symptoms in early stage, and it is about 1 times more than right hemicolectomy cancer, so such patients are often diagnosed earlier than right hemicolectomy; 70%-80% of patients in early stage of right hemicolectomy cancer often have vague pain and distension in the right side of abdomen after meals, which is aggravated by activities and occasionally paroxysmal, and appears similar to chronic cholecystitis or gastroduodenal ulcer, chronic appendicitis and other symptoms, which is easy to cause misdiagnosis.