What are the types of colon cancer

Colon cancer is a common malignant tumor of the digestive tract that occurs in the colon, and ranks third among gastrointestinal tumors. The most common sites are the rectum and the junction of the rectum and the sigmoid colon, and the disease often occurs after the age of 40. The highest incidence rate is in the 40-50 age group. According to the world epidemiological survey, the incidence rate of colon cancer is highest in North America, Western Europe, Australia, New Zealand and other places, ranking first and second among visceral tumors, but the incidence rate is very low in Asia, Africa, Latin America and other places.

The incidence and mortality rate of cancer in my country are lower than those of common malignant tumors such as gastric cancer, esophageal cancer, and lung cancer. Data from various regions show that with the improvement of people's living standards and changes in dietary structure, the incidence rate has been increasing year by year.

(I) Gross morphology

Based on the gross morphology, colon cancer can be divided into three types: mass-forming, invasive, and ulcerative:

1. Mass type: The tumor grows into the intestinal cavity, with a hemispherical or spherical protrusion and a soft texture. The tumor is large and prone to ulceration and bleeding and secondary infection and necrosis. This type of colon cancer often occurs in the right colon, most of which are highly differentiated, less invasive, and grow slowly.

2. Infiltrative type: The tumor infiltrates around the intestinal wall and grows along the submucosal membrane. It is hard in texture and easily causes intestinal stenosis and obstruction. This type of colon cancer has a low degree of cell differentiation, a high degree of malignancy, and metastasis occurs earlier. It often occurs in the large intestine outside the right colon.

3. Ulcerative type: This is the most common type of colon cancer, which is more likely to occur in the left colon and rectum. The tumor grows deep into the intestinal wall and invades the outside of the intestinal wall. Ulcers may appear in the early stage, with raised edges and deep bottoms. It is easy to bleed, get infected, and penetrate the intestinal wall. This type of cell has a low degree of differentiation and metastasis occurs earlier.

(II) Histological classification

Based on histological characteristics, colon cancer can be divided into three categories: adenocarcinoma, mucinous carcinoma, and undifferentiated carcinoma:

1. Adenocarcinoma: Most colon cancers are adenocarcinomas, and adenocarcinoma cells are arranged in glandular tubules or alveoli. According to the degree of differentiation, they are divided into grades I to IV according to the Broder method, namely low-grade malignancy (well-differentiated), intermediate-grade malignancy (moderately differentiated), high-grade malignancy (poorly differentiated) and undifferentiated cancer.

2. Mucinous carcinoma: Cancer cells secrete a lot of mucus, which can be found in the extracellular matrix or accumulated inside the cells to push the nucleus to the edge. Cells with more mucus have a poor prognosis.

3. Undifferentiated cancer: The cells of undifferentiated cancer are small, round or irregular in shape, and arranged in irregular sheets. They are poorly differentiated, highly invasive, and easily invade small blood vessels and lymphatic vessels, with a poor prognosis.