Colorectal cancer


Colorectal cancer

Colorectal cancer is a cancer that occurs in the mucosa, the innermost surface of the large intestine. It is called rectal cancer that occurs in the 15cm area from the anus. In Korea, gastrointestinal cancer frequently occurs after stomach cancer. It is also a disease that can be cured if diagnosed early.

Colorectal cancer and rectal cancer are fatal cancers seen in both Korean and English as the age increases. About 5 ~ 15% of colon cancer patients are affected by hereditary genetic factors. Among the immediate family members, 3 or more colorectal cancer patients appear in 2 families and it is reported that they are two to four times more likely to develop colon cancer than the general population. In addition, even if exposed to carcinogens, susceptibility varies depending on the genetic nature of the individual, so the mutation of the CYP2E1 enzyme, which is called as a carcinogen, can be analyzed to determine the likelihood of colon cancer. If you have colon cancer among your siblings, you are 2-3 times more likely to develop cancer. People with chronic enteritis, such as ulcerative colitis or Crohn's disease, are said to have a 20-fold increased risk of developing colon cancer. People who have constant bowel movements and constipation are more likely to have more time for the body to stay in the intestines, increasing the chance of carcinogens being absorbed into the body and increasing the incidence of cancer. It is important to change your dietary habits so that you do regular exercises so that you do not have constipation. At age 40 or older, both men and women are required to undergo rectal examinations every year and should undergo bowel endoscopy every 3-5 years. People with a family history of multiple bowel polyps or those who have had polyps removed and removed have to undergo routine screening.
In a recent clinical study of over 7,000 people, three mutations in a gene called SMAD7 were found to be strongly associated with colorectal cancer.

Incidence rate

Large intestine and rectal cancers are common in people living in the United States or Europe who eat lots of animal fat and meat. The incidence and mortality rates are the second highest in the United States, especially in the United States. The rate of incidence of colorectal cancer and rectal cancer is increasing compared with the previous years as the dietary habits have become more widespread in the Asian countries including Korea and Japan compared with the western countries. According to the recent survey (1997) For men, it is the fourth most common cancer following stomach cancer and breast cancer. Like cancer that occurs in other organs, colorectal cancer and rectal cancer usually occur after age 50, but sometimes also occur at younger ages.

Causes and Risk Factors

The causes of colorectal cancer and rectal cancer have not yet been clearly elucidated. However, the cause of familial adenomatous polyposis, idiopathic nonspecific ulcerative colitis, colon and rectal polyps, It is known. There is no evidence that colon or rectal cancer is hereditary, but it is thought to be genetic in about 10-30% of the patients.
When eating lots of animal fat and meat, the amount of stool is small and the time for the contents of the colon to pass through the large intestine is longer than that of the Oriental people who eat a lot of fibrous foods such as vegetables and grains. If you take a lot of animal fat, it will cause changes in bacteria normally present in the colon. If the contents of the colon through the large intestine are long, the substances generated during digestion of the food, especially bile, The possibility of producing cancer-causing substances is increased, and the time for these carcinogens to contact with the chondrocytes is increased, thereby increasing the incidence of colorectal cancer. Epidemiological studies have shown a correlation between the intake of animal fat and meat and the incidence of colon and rectal cancer.

January 2010 SNU University Professor Baek Seong-Hee recently revealed that the gene called ROR alpha suppresses colorectal cancer (Molecular Cell).


There are no characteristic symptoms that can be suspected of colon cancer. However, symptoms such as weight loss and general cancer symptoms may occur depending on the site of cancer development or progression. For example, when a cancer occurs in a descending colon, an esophagus, or a rectum that is close to the anus, the stool or bowel obstruction (diarrhea and constipation repeated), tapering of the stool, sweating, abdominal pain, It is not uncommon for the diagnosis to be delayed because it is mistaken for hemorrhoids. In case of cancer in the ascending colon, it may be diagnosed on the way of anemia (dizziness, nausea, loss of appetite, malaise, shortness of breath, etc.)
Other cases of obstruction of the lumen by progression of the cancer include symptoms of intestinal obstruction, abdominal masses, and metastasis to the liver or lungs rather than the primary lesion.


1. Occlusion test: The fecal occult blood test is a simple screening test for colorectal cancer. Colon cancer can not be said to be a positive reaction because occult reaction is caused by other causes.
2. Tumor markers test: It is to measure CEA (cancerous antigen) by blood test. Although it is increased in about 50% of patients with colorectal cancer, it can not diagnose colon cancer because it is high, and it helps to evaluate the high level of diagnosis or the recurrence after treatment.
3. Colonic angiography: Radiologically, it is a method to detect the colorectal cancer by looking at the contour change of the colon mucosa. The outline of the entire colon can be seen and the position of the cancer can be confirmed before surgery.
4. Colonoscopy: There is a short endoscope to observe the eschar's colon and a long endoscope to observe all the colon to the appendix. It is more accurate than colonography. A biopsy can be done to confirm the diagnosis and can remove the polyps and colonoscopy is an indispensable test for colon cancer.
5. Abdominal ultrasound or abdominal computed tomography: When colon cancer is diagnosed through colonoscopy and colonoscopy, it is a test for the local progression of disease and distant metastasis.

Stages and treatment methods

Colorectal cancer stage is classified as A, B, C, D according to the Dukes classification, depending on the extent of invasion of the large intestine mucosa, the degree of surrounding lymph node metastasis, and the presence of other organs. Each stage is determined postoperatively, like other cancers, and there is a difference in treatment and prognosis depending on the stage.

Endoscopic treatment
Recently, endoscopy has been recognized as an indispensable test for the diagnosis of colorectal cancer and plays an important role in the prevention and treatment of colorectal cancer. Endoscopic polypectomy can be used to remove the polyps that can progress to cancer before they become cancerous, thereby lowering the incidence of colorectal cancer. Endoscopic resection alone is also possible for colorectal cancer of small size.

It is a major treatment for colorectal cancer and has a significant effect on treatment outcome. In the case of the colon, it is possible to maintain the rectum according to the distance from the anus in case of the rectum. You can remove the anus and make an anus.

Radiation therapy
Rectal cancer is a treatment that is performed along with chemotherapy after surgery according to the stage. 5 days for 5 to 6 weeks for 5 days per week, and recurrence of the primary site and the pelvic lymph node transfer rate is reduced.

Anticancer treatment
In cases of colorectal cancer diagnosed as post-operative stage B, controversy over the treatment of chemotherapy is still controversial. However, in stage C colorectal cancer, 6 months to 1 year of chemotherapy is considered as the standard treatment, and in stage D, the chemotherapeutic treatment is being performed because the effect of chemotherapy is significantly reduced but other treatments are impossible.

Treatment grade

The postoperative 5 year survival rate of each stage is 90% in stage A, 80% in B, 45% in C, and less than 10% in D. Colon cancer also has a 5 - year survival rate that is significantly reduced as the cancer progresses, and early diagnosis and treatment are very important.


The definite cause of colorectal cancer and rectal cancer has not yet been determined. It is known that an increase in the incidence of animal fat and meat consumption increases. It is therefore advisable to avoid excessive intake of animal fats and to take balanced amounts of fresh vegetables and fiber-rich foods. Also, do not eat too much food containing chemicals such as dark pigments and preservatives.
There are many diseases related to colon and rectal cancer. If you have diseases such as familial polyposis colitis, idiopathic nonspecific ulcerative colitis, colon and rectal polyps, special attention is paid to periodic tests to prevent colorectal cancer and rectal cancer It is helpful.

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Working principle

Colorectal cancer is an example of how it can make the mechanism to protect the health of digestive organs very painful.

Colorectal cancer can develop in the colon or rectum. Both are part of the boss. When you eat food, food passes through the stomach and is absorbed into the small intestine that absorbs nutrients into the bloodstream. Here, the remaining digestion is placed in the colon, which is located in the first 4 to 5 feet of the large intestine. The colon absorbs water, salt, and minerals from the pathway to the rectum, which is located in the last 5 to 6 inches of the colon before the waste is made. This waste is stored here until it is released into the waste.

The vast amount of cell division that occurs in the large intestine keeps the organ functioning properly, but it also has many opportunities for cancer formation. Every hour cell division is a DNA replication that introduces possible mutations within the genetic information of its cells. The more cell division occurs, the greater the chance of mutation. While many mutations are neutral, they can affect critical genes, including DNA errors that control or regulate growth. Approximately 75% of rectal cancers are caused by spontaneous variations due to the type of gene. - This is an occasional onset of cancer.

Sounds frightening, but the glandular polyps are actually very common. Half of all people can be at least 70 years old. The length of time that a polyp can become cancer is 5-10 years - sometimes longer - which is why polyps are mostly affecting people over 50 years of age. Fortunately, your doctor may use a variety of methods for the detection and removal of polyps before the polyps develop further.

Other factors
Theoretically, any factor that increases cell division in the large intestine can increase the chance of causing colon cancer. This can explain why colorectal cancer is most commonly encountered in developed countries. Some studies have shown that eating habits in the western world, where vegetable intake is low and meat intake is high, can accelerate cell growth quickly. Excessive drinking has also been shown to increase the risk of cell division and colorectal cancer. In addition, inflammatory bowel diseases such as Crohn's disease and ulcerative colitis may cause excessive increase of colon cells, and may therefore increase the risk of colorectal cancer.
Other risk factors for colorectal cancer (and general cancer) include exposure to substances that increase the rate of DNA mutations, such as smoking. On the other side, exercise has been proposed as a way to reduce the risk of colorectal cancer. In addition, one theory for exercising effects on hormones, immune system functioning, and metabolism is that exercise promotes regular bowel movements, thereby causing harm and stimulating obesity. Exposure limits.
Although most colorectal cancer patients are sporadic due to misfortune, about 25% have inherited genetic factors. Some families have been affected by a dominant genetic mutation, which means that a carrier with the majority of mutations eventually develops colon cancer. However, their mutations only account for about a fifth of colon cancer inheritance. (Ie, 5% of all colorectal cancer patients)

The remainder of the risk for familial colorectal cancer is not usually contributing more to increased risk, but it usually results in genetic modification. However, people with a high risk of either genetic or SNPs can develop diseases.