Clinical manifestations of colorectal cancer symptoms

The symptoms of colorectal cancer are not obvious. There may be no symptoms or only vague discomfort, indigestion, occult blood, etc. As the cancer progresses, the symptoms gradually become more obvious, manifested as changes in bowel habits, blood in the stool, abdominal pain, abdominal mass, intestinal obstruction, and systemic toxicity symptoms such as fever, anemia and weight loss. Tumor infiltration and metastasis may also cause changes in corresponding organs. Colorectal cancer presents different clinical signs and physical signs depending on its primary site.

1. Left-sided colon cancer

The prominent symptoms are changes in bowel habits, mucus and blood in the stool, intestinal obstruction, etc. The left colon cavity is narrow, and primary cancer often grows in a ring-shaped infiltration, which can easily cause intestinal constriction, so constipation is common. Subsequently, due to the increase in fluid accumulation in the upper intestinal cavity and hyperperistalsis, diarrhea may occur after constipation, and the two often appear alternately. Since the stool gradually changes from a paste to a clumpy state when entering the left colon, it is common to see blood in the stool caused by the friction of the stool with the lesion. Patients often seek medical treatment earlier, and anemia caused by long-term chronic blood loss is not as prominent as in the right colon. Intestinal obstruction caused by cancer infiltration around the intestinal wall and stenosis of the intestinal cavity is mostly chronic and incomplete. Patients often have long-term constipation and paroxysmal abdominal pain. Since the obstruction site is relatively low, vomiting is often not obvious.

2. Right colon cancer

The prominent symptoms are abdominal mass, abdominal pain, and anemia. Some patients may have mucus or mucus-bloody stools, frequent bowel movements, abdominal distension, intestinal obstruction, etc., but these symptoms are much less common than those of the left colon. The right colon has a wide intestinal cavity, and the primary cancer has often grown greatly by the time it is discovered. Ulcers and masses are common, and many patients can feel a mass in the right abdomen. Unless the tumor directly affects the ileocecal valve, intestinal obstruction is generally rare. Since the stool is still semi-fluid and thin in the right colon, the bleeding caused by the stool rubbing against the cancer is relatively small. Most bleeding is caused by necrotic ulcers of the tumor. Because the blood and fecal fluid are evenly mixed and not easy to detect, it can cause long-term chronic blood loss. Patients often seek medical treatment due to anemia. Abdominal pain is also common, often dull pain, mostly caused by the invasion of the tumor wall by the mass. Secondary infection of cancerous tumor ulcers can cause local tenderness and systemic toxemia.

3. Tumor Infiltration and Metastasis

Local extension is the most common form of infiltration of colorectal cancer. Tumor invasion of surrounding tissues often causes corresponding symptoms, such as rectal cancer invasion of the sacral plexus causing persistent pain in the lower abdomen and lumbosacral region, anal incontinence, etc. Due to the implantation and shedding of cancer cells, a mass may be palpated in the vesicorectal fossa or uterine rectal fossa during rectal examination. Ascites may occur in cases of extensive dissemination. Early cancer may also spread along the lymphatic spaces around the intestinal wall nerves, and then transfer to the lymph nodes through the lymphatic vessels. When cancer cells are transferred to the para-aortic lymph nodes and enter the chylous cisterna, they may metastasize to the left supraclavicular lymph nodes through the thoracic duct, causing enlargement of the lymph nodes there. In a small number of patients, the ascending lymphatic vessels are blocked by cancer thrombi, causing cancer cells to spread retrogradely, resulting in countless diffuse nodules in the perineum. In female patients, the tumor may metastasize to both ovaries, causing Kruken-berg's disease. Advanced colorectal cancer may also metastasize to the liver, lungs, bones, etc. through the blood.

4. Rectal cancer

The prominent symptoms are blood in the stool, changes in bowel habits, and concomitant symptoms caused by infiltration of advanced cancer. The site of carcinoma in situ is low, and the feces are hard. The tumor is easily rubbed by the feces and easily causes bleeding, which is mostly bright red or dark red, not mixed with formed feces or attached to the surface of the feces column and misdiagnosed as "hemorrhoidal bleeding". Due to the stimulation of the lesion and the secondary infection of the mass ulcer, the defecation reflex is constantly induced, which is easily misdiagnosed as "bacillary dysentery" or "enteritis". The ring-shaped growth of the tumor causes the intestinal cavity to narrow, which is manifested as deformation and thinning of the feces column in the early stage and incomplete obstruction in the late stage.

The above is an explanation of the clinical manifestations of colorectal cancer symptoms. We hope that it can help you and we feel very honored. The above content is for reference only and cannot be used as a basis for diagnosis and treatment. Because each person's physical constitution is different, the degree of disease and symptoms are different, so it is recommended that all diagnosis and treatment should follow the guidance of the doctor. If you have other questions, please consult our online experts for understanding.

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