Clinical manifestations.
1.Symptoms
(1) Blood in stool The early lesions of colorectal cancer are limited to mucous membrane, so there may be no symptoms or only changes in bowel habits. When the tumor grows to a certain extent, blood in the stool will appear, and the blood will be light in color and adhere to the surface of the stool. When the size of tumor is small, the mucous membrane is still intact, so bleeding usually does not occur. As the size increases, due to inflammation, blood flow disorder, mechanical stimulation and other reasons, the mucous membrane becomes erosion, ulceration, or even tumor rupture and bleeding occurs. When there is a small amount of bleeding, it is not easy to be detected by naked eyes, while fecal microscopy can find red blood cells and positive fecal occult blood test. When the bleeding is large, it may appear as blood in the flesh. The color of bleeding in colorectal cancer is mostly dark red, and the closer the location is to the anus, the brighter the color is. Some patients may also have tarry stools similar to those formed by upper gastrointestinal bleeding because the cancer focus is located in the right hemicolectomy or near the ileocecal region and the blood stays in the intestine for a longer period of time. The amount of bleeding is not proportional to the size of the cancer, and it is not certain that it is due to cancer. Some non-malignant diseases such as intestinal tuberculosis and chronic enteritis also show blood in stool, while colorectal cancer may only have positive fecal occult blood without visual blood in stool. Because of the poor prognosis of malignant tumors, early detection can significantly improve the prognosis. Therefore, patients with bloody stools or persistent positive fecal occult blood should first be considered as possible colorectal tumors and should undergo further relevant examinations.
(2) Mucus stool and pus-blood stool.
(3) Change of defecation habit, including constipation, diarrhea or both, incomplete defecation, difficult defecation, etc. When rectal tumor grows to a certain size, it often changes the shape of stool, which is manifested as thin and deformed stool.
(4) Abdominal pain and abdominal distension are other common clinical manifestations of colorectal cancer patients, such as abdominal pain and abdominal distension. Among them, the incidence of abdominal pain is higher than that of abdominal distension. The nature of pain can be divided into vague pain, dull pain and colic.
2.Signs
(1) Anemia and wasting As the disease progresses, patients may develop chronic wasting symptoms, such as anemia, wasting, weakness and fever, and even cachexia. This is associated with blood in stool, insufficient intake and excessive consumption.
(2) Abdominal mass is one of the main manifestations of colorectal tumor. Its incidence is 47%-80%. It is the most common symptom of right hemicolectomy cancer, accounting for about 80% of patients; left hemicolectomy cancer accounts for about 20%-40%. When the tumor is confined to the intestinal wall and has no adhesion with other organs or tissues, the mass can still be pushed, or change with the body position. When the tumor invades and adheres to other tissues, the mass is often more fixed.
(3) Rectal tumor can be found in the rectal cavity with unsmooth surface, brittle and bleeding masses or ulcers, and dark brown blood stain in the finger sleeve.
3.Special manifestation of tumor in different parts
In addition to the above symptoms, the clinical manifestations are different according to the different parts of cancer. Colon cancer occurs most often in the rectum and sigmoid colon, followed by cecum and ascending colon, transverse colon, splenic flexure and hepatic flexure.
(1) Right hemi-colon cancer Right hemi-colon cancer often shows symptoms such as abdominal mass, anemia, abdominal pain, general weakness and emaciation. Abdominal pain is also one of the main symptoms of right hemicolectomy patients. Blood in stool and anemia are the more common symptoms of right hemicolectomy cancer. Anemia is the third common symptom of right hemicolectomy cancer, and the same stool occult blood test is often positive, which may appear as the first symptom.
(2) Blood in stool of left colon cancer is the most common symptom of left colon cancer, accounting for about 75%. It is often manifested as dark red blood on the surface of stool, which is easily detected by patients and attracts attention. Mucus stool or mucopurulent stool may also appear.
(3) Rectal cancer is mainly manifested by blood in stool and change of bowel habit. Blood in stool is the most common symptom of rectal cancer patients, mostly in the form of fresh blood or dark red blood, which is not confused with stool, while massive bleeding is rare. Sometimes the blood in stool contains blood clots and detached necrotic tissue. Change in bowel habit is also one of the main clinical symptoms of rectal cancer patients. The main symptom is the increase of stool frequency, from several to ten times a day, or even dozens of times a day, with only a small amount of blood and mucus in each stool, accompanied by persistent anal swelling and the feeling of incomplete defecation. The stool often becomes thin and deformed, and there is even difficulty in defecation and stool closure.
(4) Bleeding and pain are the main manifestations of anal canal cancer and anal cancer. In early stage, the tumor of anal cancer can invade the nerve and cause pain, especially when defecating, the pain is obviously intensified, so patients are afraid of defecation and cause constipation.
4.Common complications
(1) Intestinal obstruction can be caused by the enlargement of tumor, which can narrow the intestinal lumen and obstruct the passage of intestinal contents, resulting in mechanical intestinal obstruction. When the tumor grows to a certain size, it can block the intestinal lumen and cause complete or incomplete obstruction symptoms. It is characterized by progressive aggravation and difficult to be relieved by non-surgical methods.
(2) Intestinal perforation has typical clinical manifestations of acute abdomen, abdominal muscle tension, pressure pain, rebound pain, and crescentic free gas under the septum as seen in X-ray plain film, which can make the preliminary diagnosis. Acute colon perforation and peritonitis are reported to account for about 6% of colon cancer combined with colon perforation.
(3) Acute hemorrhage is a rare complication of colorectal cancer.