The large intestine is the section of the intestine that connects the small intestine to the anus. When most people hear large intestine, they probably think of stool. Indeed, the large intestine is the place where stool is produced. In a healthy adult, 80% of the stool is water, and the remaining 20%, 1/3 of which is food residue, 1/3 is intestinal bacteria, and 1/3 is metabolically shed intestinal mucosa. There are about 400 species of bacteria in the human intestinal tract, and there are about 100 billion bacteria per gram of stool.
But contrary to what you might think, the large intestine is much more than just a receptacle for producing and storing stool. The large number of bacteria in the colon not only helps us maintain a balanced flora, but also produces many essential vitamins, such as vitamin K, and also maintains the body’s water-electrolyte balance through excretion and absorption.
Colorectal cancer ranks second in the incidence of all cancers in European and American countries. In recent years, the number of colorectal cancer incidence in China has been increasing year by year. Originally, colorectal cancer was relatively rare in China, probably ranking fifth among all cancers; however, with the change of living and eating habits, such as increased intake of high fat and high protein, and insufficient exercise, the incidence of colorectal cancer in China has been increasing. According to 2012 statistics, in some big cities, such as Beijing and Shanghai, colorectal cancer has become one of the fastest rising malignancies, and now ranks second, after lung cancer.
So this has become a serious problem.
As I have said before, the key to treatment for all cancers is early detection. Colorectal cancer is one of those cancers that can be prevented, so having some knowledge about colorectal cancer not only helps to understand the risk factors for colorectal cancer, but may also prevent it from occurring.
However, there are a lot of media information about how to prevent colorectal cancer, how to conduct effective screening and how to achieve early detection, and it is very confusing because there are various statements.
First of all, let’s talk about the symptoms of colorectal cancer.
The most common symptoms of colorectal cancer include
Sudden change of stool habit, such as stool suddenly becomes very thin. Blood in the stool. It can be very red blood or black stool. Sudden constipation, diarrhea, or a feeling of not being able to poop cleanly. A sudden feeling of bloating, fullness, or cramping in the abdomen. Severe weight loss without weight loss. Fatigue and lack of energy.
Seeing here, you may also understand that except for the special manifestation of intestine, the symptoms of colorectal cancer are not so obvious and special, which can be easily ignored.
Therefore, it is very important to understand the risk factors of colorectal cancer. For those who are at high risk, they should be more alert and pay more attention to themselves.
So what are the risk factors of colorectal cancer?
Risk factors are divided into two categories. One category is what you can’t change. One category is what you can change through efforts.
The first category is the uncontrollable risk factors.
Age: The older you are, the greater your risk of getting cancer. 90% or more of colorectal cancers are acquired by people over 50 years old.
History of intestinal polyps or colorectal cancer: The risk is multiplied if you have had intestinal polyps or have had colorectal cancer before.
Inflammatory bowel disease: People who have had inflammatory bowel disease, such as ulcerative colitis, or Crohn’s disease, also have a dramatically increased risk of developing colorectal cancer.
Genetic factors: There are two familial genetic diseases that can lead to a much higher risk of colorectal cancer: one is called familial adenomatous polyposis and the other is called hereditary nonpolyp colorectal cancer.
Family history: If a family member has had colorectal cancer or colon polyps, your risk of colorectal cancer is also increased.
The second category is controllable risk factors.
Lifestyle: Obesity, smoking, alcohol consumption, and lack of exercise all raise the risk of getting colorectal cancer. Studies show that drinking 45g of alcohol per day raises the risk of colorectal cancer to 1.41 times; smoking raises the risk of colorectal cancer 1.2 times; obese people are 1.45 times more likely to have colorectal cancer than normal weight people.
Recipes: Too high a proportion of red meat in food, such as pork, beef, lamb, or too much processed meat, is also closely related to colorectal cancer. Too little dietary fiber also raises the chances of colorectal cancer.
So what can be done to minimize the chances of colorectal cancer?
Don’t ever smoke. If you smoke now, quit. Exercise more. Don’t sit all day and night. Regular exercise can reduce the risk of colorectal cancer by 24%. Don’t gain weight and maintain a proper weight. Eat as little red meat as possible, as well as processed meats such as ham and sausage. Drink as little alcohol as possible. Add more fiber to your diet, such as eating more green vegetables and fruits.
If unfortunately these risk factors are present, how can colorectal cancer be detected early?
In addition to the common symptoms mentioned above that should be kept in mind when having a bowel movement every day, there are three effective tests that can detect colorectal cancer early.
Highly sensitive fecal occult blood test, which is to check the stool. Colorectal cancer will sometimes produce a small amount of blood on the surface of the intestine, and this blood will be excreted through the stool, so checking whether there are blood cells in the stool may detect colorectal cancer at an early stage.
Sigmoidoscopy. This is a relatively short fiberscope that is inserted through the anus and can detect tumors at an early stage.
Colonoscopy. This mirror is a little longer and can examine the entire large intestine.
People over the age of 50 and under the age of 75 are recommended to receive all three types of examinations. This is done by doing a highly sensitive fecal occult blood test once a year after the age of 50, and aiming to do it every year because of its convenience and ease of use, although the sensitivity and specificity are not high, that is, false positives and false negatives are not low. Or do sigmoidoscopy every 5 years; however, because the interval is too long, if colorectal cancer happens to occur within this 5-year interval, there is a possibility of missing the test, so it is also recommended to do fecal occult blood test every 3 years. The best and most effective is colonoscopy, which is recommended every 10 years, i.e., once at age 50, 60, and 70. After age 75, the benefit of these tests in detecting cancer and reducing overall mortality decreases significantly, so it is not recommended.
This is talking about the general population, with one special exception. That is, if there is an immediate family member, such as a parent who has colorectal cancer, then the children should start these screenings 10 years before the age they get colorectal cancer: for example, if the father gets colorectal cancer at age 50, then the children should start the screenings at age 40 for early detection and timely treatment.