Twenty things you need to know about colorectal cancer

Content Tip: Colorectal cancer refers to malignant lesions of the colon mucosal epithelium caused by multiple carcinogenic factors such as the environment or genetics. It has a poor prognosis and a high mortality rate. It is one of the common malignant tumors in my country. In view of the fact that the incidence of colorectal cancer in my country has continued to increase in recent years, while the cure rate has not improved significantly, we believe that it is very necessary to carry out scientific publicity on colorectal cancer prevention and treatment knowledge. The relevant publicity knowledge is listed here. I hope everyone can master the prevention knowledge of this disease and work with doctors to -

Colorectal cancer refers to a malignant lesion of the colorectal mucosal epithelium caused by multiple carcinogenic factors such as environmental or genetic factors. It has a poor prognosis and a high mortality rate. It is one of the common malignant tumors in my country.

In view of the fact that the incidence of colorectal cancer in my country has been increasing in recent years, while the cure rate has not improved significantly, we believe that it is very necessary to carry out scientific publicity on the knowledge of colorectal cancer prevention and treatment. The relevant publicity and education knowledge is listed here. We hope that everyone can master the prevention knowledge of this disease, work with doctors to prevent and treat colorectal cancer, and make some contributions to improving the health quality of the whole people.

1. Why are there more and more patients suffering from colorectal cancer? What is the reason?

Here are two sets of data: one is a comparison of the incidence of colorectal cancer in five provinces and cities over the past 20 years, and the other is a comparison of census figures in recent decades (plus two slides). These two figures show that the number of people suffering from colorectal cancer in my country is indeed on the rise. According to the research results of experts from various countries, most people believe that long-term high-protein, high-fat and low-fiber diets are conducive to the occurrence of colorectal cancer. Of course, it does not mean that long-term high-protein, high-fat and low-fiber diets will cause colorectal cancer. Other related factors, such as long-term unhealed ulcerative colitis; multiple family members suffering from colorectal cancer or polyposis; cholecystectomy for more than 10-20 years; lower abdominal radiotherapy; chronic schistosomiasis infection, etc. are also related to the incidence of colorectal cancer.

2. Some people say that "the better you eat, the more likely you are to get colorectal cancer." Is this true?

The incidence of colorectal cancer in different regions and countries around the world can differ by more than 10 times. The incidence of colorectal cancer in economically developed regions and countries, such as North America, Western Europe, Australia and New Zealand, exceeds 25-35/100,000. In the past 20 years, Japan, which was originally a high-incidence country, has seen an increase in the incidence of colorectal cancer as its economy has developed rapidly. According to statistics, from 1969 to 1981, the mortality rate of colorectal cancer in Japanese men increased by 44%, and that in women increased by 40%. On the contrary, the incidence rate in India is only 1-3/100,000, and the incidence rate in some African countries is even lower than 1/100,000. Statistics from the past 30 years in my country show that the incidence rate of colorectal cancer has increased from <10/100,000 in the 1960s to more than 20/100,000 in the 1980s. The mortality rate of colorectal cancer in Shanghai increased by 75% from 1972 to 1989. According to experts' estimates, after 2000, the number of cases of colorectal cancer will be 1.45 times higher than that in the 1980s. According to our survey data of more than a dozen towns in northern my country, the incidence of colorectal cancer in cities, especially large cities, is significantly higher than that in small towns and rural areas. In cities, the incidence of people with less physical activity is higher than that of people with more physical activity. From the results of various countries' research on the etiology of colorectal cancer, high-fat, high-protein diet, reduced exercise, environmental pollution and bad habits are all related to the incidence of colorectal cancer, and the emergence of the above social conditions is also related to economic development. Based on this, some people believe that the better you eat, the easier it is to get colorectal cancer. In fact, colorectal cancer, like other cancers, is the result of the interaction between environmental factors and genetic factors. As far as diet itself is concerned, a high-fat, high-protein, low-fiber diet may play a certain role in promoting colorectal cancer.

3. Since a diet high in fat, protein and low in fiber (whole grains, vegetables and fruits are high-fiber foods) is likely to cause colorectal cancer, what kind of diet is a "healthy diet"?

Recently, the U.S. Department of Agriculture recommended a "pyramid" food structure diagram, which they believe is conducive to the prevention of colorectal cancer. The bottom of the pyramid is composed of various grains, pasta, and rice, the middle of the pyramid is vegetables and fruits, the top of the pyramid is meat, poultry, aquatic products, eggs, beans and dairy products, and the top of the pyramid is high-fat food. In fact, this food structure is exactly the daily diet in Asia, especially in my country. From the perspective of preventing colorectal cancer, maintaining my country's traditional dietary structure is a "healthy diet."

4. Are people with this condition more likely to get colorectal cancer?

It refers to the symptoms of too few bowel movements, difficulty in defecation, and dry stool. Generally speaking, if you defecate once every 2-3 days, it cannot be called a bowel movement if the stool is smooth. Our feces contain a carcinogen, medically known as "secondary bile acid", which comes from the bile secreted by the liver. When we eat, especially when we eat oily foods, the gallbladder contracts and discharges the stored bile to help digestion. The bacteria in the intestinal cavity decompose the bile that enters the intestinal cavity into "secondary bile acid" and stay in the feces. The "secondary bile acid" in the intestinal cavity is in contact with the intestinal mucosa for a long time, which increases the chance of continuous stimulation of the mucosa. From this perspective, it will be conducive to the occurrence of colorectal cancer. Of course, in addition to "secondary bile acid" in the feces, there are also many digested food residues and bacteria. The toxins produced by bacteria and the toxic products fermented by bacteria stay in the intestinal cavity for a long time, which has an adverse effect on the human body due to the stimulation of the intestinal mucosa and the absorption of some water-soluble substances. Although it cannot be said that it can induce colorectal cancer, it can be said that it has a role in fueling the occurrence of colorectal cancer. For this reason, developing the habit of regular bowel movements to prevent the occurrence of colorectal cancer is also of certain significance in the prevention of colorectal cancer.

5. Are patients who have undergone cholecystectomy more likely to develop colorectal cancer?

The gallbladder is like a "reservoir" for storing bile. Most of the bile secreted by the liver is usually stored here. After we eat, especially after eating foods with a lot of fat, the gallbladder contracts and discharges the stored bile into the intestines to help digestion and absorption. If the gallbladder is removed, the bile secreted by the liver has no place to be stored, so the bile continues to be discharged into the intestines. As mentioned earlier, the bile that enters the intestines is decomposed by bacteria in the intestines to produce "secondary bile acid" with carcinogenic effects. This carcinogen acts on the intestinal mucosa all year round, and it is possible to cause the stimulated intestinal mucosa to become cancerous. According to many Western research reports, this cancer process takes about 10-15 years. However, some researchers hold an opposing attitude. They observed thousands of patients who had undergone cholecystectomy and those who had not undergone this operation, and found that the chances of these two types of people suffering from colorectal cancer were similar. Therefore, so far, it cannot be said with certainty that patients who have undergone cholecystectomy are more likely to get colorectal cancer.

6. Can chronic colon cancer develop into colorectal cancer?

People usually refer to long-term abdominal pain as chronic colon cancer. In fact, chronic abdominal pain is not necessarily "chronic colon cancer", and even "chronic colon cancer" diagnosed by doctors is not always related to colorectal cancer. A type of chronic colon cancer that is truly related to colorectal cancer is medically called "ulcerative colon cancer". This disease is relatively rare in my country. Its main symptoms are abdominal pain, blood or pus in the stool, and fever in severe cases. Once the disease occurs, it often lasts for a long time and cannot be cured. Colonoscopy can reveal widespread ulcers and inflammation in the large intestine. Most of these patients can recover after regular treatment by doctors. Among the very few patients with severe ulcerative colon cancer who have not healed for many years, there is a greater chance of developing colorectal cancer than normal people. According to statistical data, the following two factors are more closely related to cancer:

The larger the lesion, the higher the risk of cancer (after 20 years of illness, the chance of cancer in patients with full colon is twice as high as that of left colon, and the average age of cancer is 5-10 years earlier than the latter); the longer the ulcerative colitis lasts, the greater the chance of cancer. The chance of cancer in the first 8 years after illness is only less than 1%, and then the chance of cancer increases by 0.5-1% each year, and the chance of cancer can reach 5-10% after more than 20 years. Therefore, full colon ulcerative colitis that does not heal for more than 10 years should be regarded as a "precancerous disease" and should be closely followed up and treated.

7. Can radiation therapy (commonly known as electric heating) cause it?

Many research data show that the chance of developing cancer increases significantly after receiving radiation therapy for female reproductive organ (ovarian, uterine) tumors. Therefore, women with a history of lower abdominal radiation therapy (electrotherapy) should be vigilant and undergo colonoscopy in a timely manner if rectal symptoms (blood in the stool, prolapse, changes in bowel habits, etc.) occur.

Radiation-induced cancer does not have familial clustering, which is different from another medically known as "hereditary non-polyposis colon cancer", which has prominent hereditary characteristics. This type of patient has colorectal cancer and may or may not have female reproductive organ tumors at the same time. Since this type of tumor has familial clustering characteristics, not only the patient should be treated, but also his relatives should be examined and treated (which will be discussed later).

8.Is colorectal cancer hereditary?

Scientific research has proven that most human diseases are affected by genetic factors. With the exception of trauma, almost all diseases are affected by both environmental and genetic factors, but some diseases are more affected by environmental factors, while others are more affected by genetic factors. Colon cancer is no exception. If a person has relatives with colon cancer, he or she will have a greater chance of developing colon cancer under certain conditions, such as eating high-protein, high-fat, low-fiber (refined rice, refined grains) foods for a long time. Of course, the occurrence of colon cancer is not a simple 1+1=2 (genetics + high-fat diet = colon cancer), but a multi-factor, multi-step, long-term accumulation of carcinogenic factors.

Internal factors are the basis for change, and external factors are the conditions for change. If you lack the genetic background for colorectal cancer, you are not likely to get colorectal cancer even if you are affected by carcinogenic factors. On the contrary, if you have a family history of colorectal cancer, you are more likely to get colorectal cancer under the influence of certain carcinogenic factors. Therefore, if there is a colorectal cancer patient among relatives, especially direct relatives, every member of the family should undergo regular examinations. If necessary, treatment should be carried out to prevent the occurrence of colorectal cancer.

9.Why are some colorectal cancers more likely to be inherited? Which colorectal cancers are more likely to be inherited?

As mentioned above, it should be said that all colorectal cancers are affected by genetic factors, but their genetic strength is different. There are two types of colorectal cancer that are very strongly inherited: the first type is medically called "familial adenomatous polyposis" and the second type is called "hereditary non-polyposis colorectal cancer". These two types of colorectal tumors account for only a very small number of all colorectal cancers. The average age of onset of the former is only 20 years old. There can be hundreds or thousands of adenomas (a benign tumor that grows from the intestinal mucosa) in the large intestine. Ten years after the appearance of these benign tumors, some of them begin to become cancerous. As time goes by, people with this disease will sooner or later become cancerous, and many family members have the same disease. People with this disease can also suffer from bone tumors and brain tumors at the same time. Once this disease is discovered, the patient and his immediate family members need long-term follow-up and necessary examinations. The latter (hereditary non-polyposis colorectal cancer) occurs 15-20 years earlier than general colorectal cancer. Cancer often occurs in the right colon. Sometimes there are several cancers in the large intestine at the same time (called multiple primary cancers), and it is easy to relapse after surgery. Other cancers also often appear in his family, such as ovarian cancer, pancreatic cancer, etc., so some people call it "cancer family syndrome."

Both types of colorectal cancer are highly hereditary. Once this tumor appears in a family, all the patient's immediate family members should go to the hospital for examination to achieve the goal of early detection, early diagnosis and early treatment.

10. Will all colon polyps turn into cancer?

First of all, we need to understand what "polyps" are. The so-called "polyps" refer to various protrusions that grow in the intestines (mucosal surface). Medically speaking, these polyps are divided into two types: tumorous and non-tumorous. The former is called "adenoma", which is a true benign tumor. The latter polyps are not tumors, including inflammatory polyps, hyperplastic polyps, etc., and they have nothing to do with the occurrence of cancer.

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