[Fat Bear Science] More than 90% of colorectal cancers are caused by it, check to see if you are affected

Two weeks ago, Fat Bear popularized knowledge about colorectal cancer, telling everyone that the malignant process from polyps to cancer usually takes 5-10 years, so colonoscopy can effectively prevent it for high-risk groups.

A friend left a message in the background, saying that experts say 90% of colorectal cancer is caused by malignant polyps, so how can we prevent colorectal polyps? How to treat colorectal polyps after they are found?

Well, since someone has asked the question sincerely, based on the principle of popularizing science, let’s talk about colon polyps today.

Chen Weiqing

Director, chief physician, professor, and doctor of the Department of Gastroenterology at the Affiliated Cancer Hospital of Chongqing University. He has conducted in-depth research on the clinical diagnosis and treatment of gastrointestinal bleeding, severe pancreatitis, cirrhosis and its complications, inflammatory bowel disease, etc. He is particularly good at gastrointestinal, hepatopancreatic and other diseases and endoscopic diagnosis and interventional treatment. Clinic hours: Monday morning

Zhang Jianwei

Department of Gastroenterology, Affiliated Cancer Hospital of Chongqing University, attending physician, master's student, specializes in the diagnosis and treatment of early gastrointestinal cancer, diagnosis and treatment of gastrointestinal bleeding, diagnosis and comprehensive treatment of acute and chronic liver diseases, etc. Proficient in various endoscopic operations and treatments. Published 4 SCI papers and presided over the National Natural Science Foundation Youth Fund Project.

A good life with lots of fish and meat will lead to bad polyps in the large intestine

With the changes in modern people's living and eating habits, more and more patients are found to have colorectal polyps through colonoscopy.

How do polyps develop? As a digestive system disease, colorectal polyps are closely related to dietary structure. Intake of a large amount of "high-fat, high-protein, high-energy" diet can promote the secretion of bile, which can be converted into secondary bile acid under the action of intestinal flora. Secondary bile acid has a cytotoxic effect on colon crypt epithelial cells and can cause irreparable cell DNA damage. These damaged cells gradually evolve into polyps.

Plant cellulose can increase the amount of stool, shape the stool, retain moisture in the stool, dilute carcinogens in the intestines, promote the excretion of carcinogens, and absorb bile salts that are harmful to the intestines. Insufficient intake of plant cellulose is not conducive to the excretion of harmful substances and will increase the incidence of polyps.

"Meat pimples" growing inside the intestine

The large intestine can be divided into five parts: the cecum, appendix, colon, rectum and anal canal. Colon polyps are a general term for all growths that protrude into the intestinal cavity, like "lumps of flesh" growing on the inside of the intestinal tube.

Colorectal polyps include neoplastic growths and non-neoplastic growths. These two types of polyps are not easy to distinguish clinically and can be called polyps before their pathological properties are clarified. Therefore, what is clinically called colorectal polyps does not indicate the pathological properties of the polyps.

Through colonoscopy, you can see polyps of different sizes and shapes. The small ones are only a few millimeters, and the large ones can be several centimeters. Some look like mushrooms, some look like mulberries, and some look like protruding hills. The number can vary from one to several, and even the entire intestine is covered with polyps.

Many times, even if polyps grow in the intestines, the body does not have any abnormal symptoms, and many people only discover them during physical examinations.

At least 90% of colorectal cancers develop from polyps.

At present, it has been confirmed that at least 90% of colorectal cancers evolve step by step from colorectal polyps.

The process of normal mucosa ➨ hyperplasia ➨ adenoma formation ➨ adenoma canceration usually takes 5-10 years, but some people can progress very quickly. For example, patients with familial adenomatous polyposis have large and small polyps in their intestines when they are young, and canceration is inevitable.

It should be noted that the larger the diameter of the polyp, the higher the chance of canceration, and the incidence rate also increases with age. Colorectal cancer is more common in middle-aged and elderly people, but in my country, colorectal cancer is showing a trend of younger people, which is closely related to factors such as environment, genetics, and lifestyle habits.

The Chinese Guidelines for Early Colorectal Cancer Screening and Endoscopic Diagnosis and Treatment recommend that the starting age for colorectal cancer screening be 50. Therefore, it is recommended that people over 50 years old, regardless of whether they have symptoms or not, should undergo a colonoscopy for early detection and early diagnosis and treatment.

For high-risk groups, regular screening for colorectal cancer should be started at the age of 40. This is because people with a family history of colorectal cancer, a low-fiber diet, smoking and drinking, eating red meat and processed meat, low physical labor, and obesity have a higher risk of cancer than the general population.

Different polyps have different chances of becoming cancerous

Hyperplastic polyp: The most common type of polyp is the reaction of normal mucosa to external stimuli. It is a benign lesion with a very low rate of canceration.

Inflammatory polyps: also known as pseudopolyps, are polyp-like granulomas formed by long-term chronic inflammatory stimulation of the intestinal mucosa, and are often seen in patients with colitis.

Tubular adenomas: Benign polyps that originate in the rectum or colon are called adenomas and can become cancerous. Adenomas are very common, especially after the age of 50. The chance of these polyps becoming cancerous is about 1% to 5%.

Villous adenoma: Less common, mostly solitary. Most common in the rectum, followed by the sigmoid colon. This type of polyp has a higher rate of canceration, more than 10 times higher than tubular adenoma.

Mixed adenoma: The cancer rate of this type is between tubular adenoma and villous adenoma.

Current research shows that more than 95% of colorectal cancers are caused by the transformation of adenomatous polyps among colorectal polyps, and adenomatous polyps have been recognized as a precancerous disease of colorectal cancer.

Endoscopic surgery can be used for resection, but the risk of recurrence should be noted

With the development of medical technology, endoscopic polypectomy has the advantages of less trauma, high safety, fewer complications and low cost, and has become the preferred method for the treatment of colorectal polyps. However, for those polyps with a wide range and large volume, endoscopic resection is difficult and still requires surgical treatment.

After the intestinal polyp is removed, the intestinal environment does not change, and the genetic factors will not change, so there is still a possibility of recurrence. Therefore, timely removal of colorectal polyps and regular follow-up can effectively reduce the risk of colorectal cancer. It is generally believed that the growth of intestinal polyps will gradually stop after the age of 80, especially those who are obese, have high blood lipids, and have a family history of polyps are more likely to grow polyps.

Three common problems

Q1: How do colon polyps “hide”?

Most patients with colorectal polyps may not have any clinical symptoms. They have been "lurking" silently in our bodies and are not easy to be detected. Even if digestive tract symptoms such as abdominal distension, diarrhea, and constipation occur, they are often ignored because the symptoms are mild and atypical.

Some larger polyps can cause intestinal symptoms such as changes in bowel habits, increased frequency, mucus or bloody stools, and occasional abdominal pain. A very small number of patients may experience long-term bloody stools or anemia, and swelling protruding from the anus during bowel movements.

Q2: When should I have a follow-up check-up if polyps are detected?

The Chinese Society of Gastroenterology recommends that people at high risk of colorectal cancer should undergo colonoscopy screening every 3 years. Clinically, the time for follow-up is usually determined based on the results of colonoscopy pathology, completeness of resection, intestinal preparation, health status, family history of polyps, and past medical history. For low- and medium-risk polyps, the recommended follow-up time is within 1-3 years after polypectomy.

In the following cases, it is recommended to have a colonoscopy review within 3-6 months:

■ Poor bowel preparation, failure to achieve high-quality bowel preparation, affecting the inspection field of view;

■ Various reasons led to failure to complete the full colon examination last time;

■ The total number of polyps removed at one time exceeds 10;

■ Sesamoid polyps larger than 1 cm are excised piecemeal;

■ Villous polyps larger than 1 cm with severe dysplasia;

■ When the polyp has become locally cancerous but has not reached the submucosal layer or has exceeded the submucosal layer and no additional surgical resection is desired.

Q3: Which groups of people are likely to be targeted?

Family history of digestive tract tumors;

Have a history of inflammatory bowel disease;

Have a history of long-term chronic constipation, chronic diarrhea, or bloody stools;

History of chronic appendicitis or appendectomy, biliary tract disease, or diabetes;

A history of lower abdominal radiotherapy;

The occurrence of polyps is also related to factors such as low-fiber diet, long-term smoking and drinking, and advanced age.

To prevent intestinal polyps, start from the following aspects

1. Develop good living habits

Tobacco and alcohol are extremely acidic substances. Alcohol stimulation will aggravate the stimulation of polyps. People who smoke and drink for a long time are very likely to develop an acidic constitution and induce intestinal polyps. Therefore, quitting smoking and limiting alcohol consumption is very necessary. At the same time, maintaining good bowel habits can help prevent the occurrence of intestinal polyps.

2. Keep a good diet

Keep a light diet, eat more fiber-rich foods such as vegetables and fruits, avoid constipation caused by low fiber, and eat less processed meat products, which can effectively reduce the occurrence of polyps. Studies in recent years have shown that some drugs such as aspirin may help prevent the occurrence of polyps.

3. Keep a good mood

Stress is an important cause of intestinal polyps. When a person is overly nervous, the sympathetic nerves that control the peristalsis of the internal organs are excited, inhibiting gastrointestinal motility and leading to constipation. Therefore, maintaining a good mood and having a good attitude to deal with stress are also important measures to prevent intestinal polyps.

4. Exercise

Appropriate exercise can enhance gastrointestinal motility, accelerate the excretion of feces, and reduce the occurrence of polyps.

5. Maintain a regular routine

Life should be regular. People with irregular living habits, such as staying up late for a long time, singing karaoke all night, and other irregular life habits will aggravate the acidification of the body and are prone to intestinal polyps.

Text/ Fat Bear Picture/ Internet (Please contact to delete)

Review/Chen Weiqing and Zhang Jianwei

Member of China Medical We-Media Alliance

Science Popularization China Co-construction Base

Chongqing Science Popularization Base/Chongqing Health Promotion Hospital

Chongqing Municipal Science and Technology Commission Science and Technology Communication and Popularization Project

National Health Commission National Basic Public Health Service Health Literacy Project