Colorectal cancer has received increasing attention in China. It is now one of the leading causes of mortality in both men and women. However, if detected early, there is a high hope for cure. If detected early, more than 95 percent of patients can be completely cured. In fact, the most amazing thing is that if precancerous polyps can be removed, the tumor will not occur. Precancerous polyps are usually present for many years before they become cancerous. Removal of such polyps can prevent cancer and thus reduce cancer deaths. Therefore, if caught early, colorectal cancer is one of the most curable tumors.
What is colorectal cancer?
All tissues and organs in the body are made up of cells. The growth rate of cells in the normal body is stable and controlled. New cells are usually formed to replace senescent or damaged cells. Occasionally, some cells proliferate out of control and have abnormal, invasive properties into other tissues and organs. These cells can deplete the body’s energy and disrupt its functions. These abnormal cells are called cancer and are a group of abnormal out-of-control cells. Cancer can lead to severe malnutrition and dysfunction of the affected organs. Moreover, cancer cells have the property of spreading to tissues outside the affected organs. A malignant tumor or cancer not only grows at the primary site (also called primary cancer), but its cells can also metastasize to other organs to form secondary tumors. These secondary tumors are called metastases, and metastasis is a characteristic of malignant tumors. Colorectal cancer originates in the innermost layer of the colorectum, a surface layer also known as the colorectal mucosal layer. Colorectal cancer occurs when cellular changes such as those described above occur.
What may be a protective agent against colorectal cancer?
Small doses of aspirin (80 mg) after polyp removal have been reported to reduce the rate of polyp recurrence by 19%. In patients with severe adenomas or advanced carcinomas, the reduction was about 40%. The protective effect of high doses was instead reduced, with only a 4% reduction in adenoma recurrence and a 19% reduction in adenoma recurrence in severe adenomas or advanced carcinomas. Many studies have shown that non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and size of familial adenomatous polyposis (FAP). However, these drugs can cause many stomach upsets and ulcers. A new family of NSAIDs, called COX-2 inhibitors, has recently been shown in preliminary trials to be effective without gastric side effects. Further trials are currently underway.
The safest and most effective way to prevent rectal cancer today is to remove all polyps in sight with a colonoscope. Regular exercise is important to maintain good health and help prevent colorectal cancer. Light physical activity, including walking, swimming or biking, jogging or aerobic training, 3 to 5 times a week will certainly help maintain a healthy body and promote the body’s immune function to fight infections and tumors. Certain environmental factors, including excess red meat, fat, excessive calorie and alcohol intake, obesity, an inactive lifestyle and smoking are all associated with increased risk factors for colorectal cancer. Appropriate lifestyle modifications may help in the prevention of colorectal cancer.
Who is at high risk for colorectal cancer
The high-risk groups of colorectal cancer include
1, Very strong family history of colorectal tumors or first-degree relatives with other related tumors.
2.Previous history of colorectal adenoma or cancer.
3. History of chronic ulcerative colitis or Crohn’s disease.
A very important pathological mechanism of colorectal cancer is its possible hereditary nature. If a first-degree relative has colorectal cancer, the likelihood of developing colorectal cancer is 3 to 4 times higher than normal. Patients who have previously had colorectal cancer are 3-4 times more likely to develop a second intestinal tumor, so patients with colorectal cancer need lifelong follow-up. Patients with adenomas, especially FAP (a genetic condition in which patients have hundreds of polyps), have an increased risk of developing cancer unless all polyps are removed. Patients with chronic ulcerative colitis or Crohn’s disease, especially if the history is 10 years or more, have an increased risk of colorectal cancer.
What are the early signs and symptoms of colorectal cancer
The colorectum is a hollow muscular tube that digests food and allows waste products to be expelled. When this channel is disturbed, symptoms can occur. However, because of the elasticity and large capacity of the intestine, symptoms are usually mild or late. As a result, 60% of patients with colorectal cancer present with lymph node metastasis or distant dissemination. Symptoms depend on the stage of the disease as well as the location of the tumor. In the early stage of the lesion, most patients have no symptoms. The most common symptom is rectal bleeding, which can be seen in benign adenomas and malignant tumors. Often very small amounts of blood cannot be detected by the naked eye but can be detected.
The following summary can be used for reference
1.Blood in the stool
2.Unexplained change in stool habit with loose stools
3.Unexplained weight loss
4.Recent abdominal cramps
5.Incomplete bowel movement even after defecation.
What kind of tests the doctor may give me
Usually your doctor will take a detailed medical history and consider it in the context of your past medical and family history. The doctor will then give you a physical examination that will include a rectal exam and anoscopy. You may then be asked to have a fecal occult blood test, a blood test and a colonoscopy or barium enema. If a tumor is confirmed, an ultrasound or CT scan of the liver will also be required.
Is the CEA test useful?
Carcinoembryonic antigen (CEA) is a protein that can be detected inexpensively and easily. low levels of CEA are normally measured in the digestive tract of embryos and infants, as well as in the pancreas, lungs and liver cells. pregnancy, smoking, inflammation and respiratory, hepatobiliary and digestive tumors can cause moderate increases in CEA. This test is not intended for screening and is only relevant once the diagnosis of colorectal cancer has been established. However, if CAE is elevated in a normal person, further investigation for colorectal cancer is necessary.
What are the methods to examine the colon?
1.Barium enema
This is a special X-ray test in which a dye (barium sulfate) and air are instilled through the anus in order to observe the large intestine. Although it is not as accurate as colonoscopy, it can still detect most polyps and cancers. One disadvantage is that polyps cannot be removed for biopsy at the same time. The stool may turn white for a few days after the test due to the excretion of barium sulfate, so there is no need to worry.
2.Colonoscopy
It is the gold standard method for detecting colon lesions. The bowel must be completely prepared before this test to be successful. Most modern laxatives need to be combined with drinking 2 liters of plain water, which will produce 2 to 6 watery diarrhea within 1 hour after taking the laxative. Sedation may be used during the examination, but most patients experience only mild tolerable discomfort without sedation. Patients who do not need sedation can be observed during the examination at the same time, and the doctor can indicate any lesions to you in time to help you better understand your situation. Although not applicable to all people, there is some discomfort as well as low risk, but these are not sufficient reasons to refuse the use of total colonoscopy to screen for colorectal cancer and polyps. Therefore all people who wish to do so and understand its low risk should undergo this test.
3. New imaging tests
New imaging tests such as pill colonoscopy, simulated colonoscopy, and robotic colonoscopy are being investigated and are already being used experimentally in some centers. Simulated colonoscopy is for diagnostic purposes only, and if polyps are found it means that a fiberoptic colonoscopy is needed to remove the lesions found.
What are the different stages of colorectal cancer?
Dukes depth of invasion 5-year survival rate
A confined to the intestinal wall 98%
B Invasion of the entire intestinal wall 70%
No lymph node invasion
C1 Invasion of regional lymph nodes only Vascular root lymph nodes not invaded
C2 Invasion of lymph nodes at vascular ligation 15%
D metastasis to other organs 5%
Do all family members need to be screened for colorectal cancer?
It is important to know the family history of tumor. There is a special category of families that have many members with colorectal cancer. There is another group of families that have not only more colorectal cancers but also more urological and female genital tumors. Both of these special families usually have members who develop cancer at a very young age (under 40 years old). Screening should be started earlier for members of these families than for the general population. Families at high risk for colorectal cancer refer to HNPCC (hereditary non-adenomatous colorectal cancer) and FAP (familial adenomatous polyposis). However, if there is only one colorectal cancer patient in the family and he/she is over 50 years old, then the other family members only have the same low risk as the norm. This family member will only start screening when he or she reaches the same age as the general population that requires screening, unless there is another specific reason.