I. What is colon cancer?
The large intestine includes cecum, colon and rectum, with a total length of about 1.5 meters. The colon is further divided into ascending colon, transverse colon, descending colon and sigmoid colon. Clinically, the right half of the cecum, ascending colon and transverse colon are called the right half of the colon; the left half of the transverse colon, descending colon and sigmoid colon are called the left half of the colon. Colorectal cancer is the general name of colon cancer and rectal cancer, among which rectal cancer is more common, accounting for about 60%.
What is the incidence of colorectal cancer in China?
Colorectal cancer is one of the common malignant tumors in China, with more than 100,000 new cases every year. In different regions, the incidence rate ranks the 3rd-5th among all malignant tumors and the mortality rate ranks the 4th-5th among all malignant tumors. At present, the incidence rate of colorectal cancer in China is still on an increasing trend.
What are the causes of colorectal cancer?
The etiology of colorectal cancer is complex and closely related to lifestyle, which is the result of the interaction of many internal and external factors.
What are the risk factors related to colorectal cancer?
Dietary factors: excessive intake of high-calorie animal fat and animal protein, pickled, smoked and fried foods, lack of vegetables and fiber foods.
Physical activity: prolonged work in a sedentary position and lack of moderate physical activity can affect intestinal motility
genetic factors: at least 15% of colorectal cancer patients have a genetic predisposition
Disease factors: chronic inflammation of the intestine, chronic constipation, intestinal polyps, adenomas, etc.
Other factors: obesity, smoking, mental trauma, etc.
V. Colorectal cancer can be detected early
The natural history of colorectal cancer is long, and the development from precancerous lesions to invasive tumors has to go through many genetic changes, which takes about 10-15 years according to the current research estimates, which provides opportunities for census and screening tests to detect early lesions.
Normal epithelium -> hyperplastic microadenoma -> adenoma -> intestinal cancer -> metastasis
VI. How to detect colorectal cancer at an early stage?
Since there are no specific symptoms in the early stage of colorectal cancer, once obvious symptoms appear, it is often in the middle and late stage. Therefore, it is necessary to conduct screening among asymptomatic people so that precancerous lesions can be detected in time and treated early to stop the development to cancer. Even if early cancer is detected, the 5-year survival rate of early treatment can exceed 90%.
7.How to do colorectal cancer screening?
The common methods of colorectal cancer screening are: fecal occult blood test (FOBT), questionnaire survey, rectal finger examination and colonoscopy. Different screening programs are selected according to different groups of people.
VIII. How to choose the screening program
1.Screening program for sporadic colorectal cancer
About 70%-80% of colorectal cancers have no obvious genetic background, which is called sporadic colorectal cancer. For the general population, age >= 40 years old, fecal occult blood test (FOBT) should be performed once a year. For high-risk subjects, colonoscopy is performed, and those who are positive are treated according to treatment principles; those who are negative are re-examined once a year for FOBT, and tumors detected by re-screening are treated according to tumor treatment principles, and polyps detected are re-examined by colonoscopy once every 3-5 years after removal.
2.Screening program for members with family history of hereditary colorectal cancer
(1) Members with family history of familial adenomatous polyposis (FAP) are recommended to be tested for gene mutation, if the test result is negative, it is the same as the screening of sporadic colorectal cancer; if the test result is positive and the age is >= 20 years, whole colonoscopy should be performed to detect new organisms and treat them accordingly; if the colonoscopy is negative, whole colonoscopy should be performed once a year.
(2) Members with a family history of hereditary non-polyposis colorectal cancer (HNPCC) should first undergo immunohistochemistry and microsatellite instability testing; if both are negative, their screening is the same as sporadic colorectal cancer; if one of them is positive, gene mutation detection analysis is required. If the gene mutation test is positive, whole colonoscopy should be done once at the age of 20-25 years or 10 years below the minimum age of incidence in the family, and then FOBT follow-up should be done every year, and whole colonoscopy should be done every year from the age of 40 years; if the gene mutation test is negative, whole colonoscopy should be done every 2-3 years from the age of 40 years.
9. What is a high-risk group?
For those who have no hereditary family history, age >= 40 years old, and have one of the following as high-risk subjects.
1.positive fecal occult blood test by immunoassay.
2.History of first-degree relatives with colorectal cancer.
3.History of cancer or intestinal polyps in themselves.
4.People who have two or more of the following at the same time
Chronic constipation, chronic diarrhea, mucus and blood stool, history of adverse life events (such as divorce, death of close relatives, etc.), and history of chronic appendicitis.
X. What is familial adenomatous polyposis (FAP)?
FAP is an autosomal dominant syndrome with adenomatous polyps and microadenomas spread throughout the large intestine with more than 100 in number as clinical manifestations. Patients begin to develop adenomas in their teens, and if left untreated, 100% of them will transform into colorectal cancer by the age of 40.
XI. What is hereditary non-polyposis colorectal cancer (HNPCC)
This is also an autosomal dominant disease with the following main clinical features: family aggregation, tumors mostly located in the right hemicolectomy, tendency to have multiple colorectal tumors at the same time or at different times, and good tendency to have related extraintestinal tumors (such as endometrial cancer and ovarian cancer), etc.
12.How to distinguish whether it is colorectal cancer or colorectal polyps?
Any examination, including colonoscopy, final determination needs to rely on pathological diagnosis, that is, when abnormal growths are found in the large intestine, biopsy must be done, and only pathological diagnosis is the basis for confirming colorectal cancer.
XIII. How to avoid misdiagnosis of rectal cancer?
The most common symptom of rectal cancer is blood in stool and change of stool habit, which is often misdiagnosed as “hemorrhoids” and “enteritis” at the early stage of development. Therefore, first of all, we should raise the vigilance and awareness of rectal cancer. In case of mucus and blood stool, change of stool habit, deformation of stool, and discomfort of anal swelling, in addition to fecal occult blood test, we should do rectal finger examination, and most of the tumors in the middle and lower rectum can be detected by rectal finger examination.
XIV. What are the symptoms and manifestations of colon cancer?
The symptoms and manifestations of colon cancer mainly depend on the location, size, type, growth rate and duration of the cancer. If it occurs in the left hemicolectomy, the common symptoms are increased stool frequency, blood and mucus in stool, and change of stool habit such as thin stool shape; while if it occurs in the right hemicolectomy, the bleeding is often mixed with stool evenly, which is not easily detected by naked eyes.
XV. Diagnostic steps of colorectal cancer.
The steps of diagnosing colorectal cancer should be performed in the order of medical history (detailed inquiry about symptoms, including family history), physical examination (rectal finger examination must be done), laboratory tests (such as fecal occult blood test, blood routine, etc.), ultrasound (to detect liver metastasis, etc.), colonoscopy (the most critical means of diagnosis) or barium enema X-ray examination. If necessary, supplemented by CT, MRI, ECT and other examinations to understand the lesions and metastases.
16.How to deal with colorectal cancer once it is detected?
Once colorectal cancer is detected, one should go to a regular hospital with conditions for tumor treatment as soon as possible, and the first standardized treatment plan will play a crucial role in prognosis. Surgery is still the main means of treating colorectal cancer, according to the different parts of the lesion and the early and late stages of the disease, the surgical methods are different, and the treatment plan also varies from individual to individual, part of the early colorectal cancer can be removed under endoscopy, avoiding the pain of open surgery.
17. How to prevent colorectal cancer
1. Promote healthy lifestyle and try to avoid and eliminate risk factors.
Have a reasonable diet and adjust the diet structure: avoid excessive fat intake, increase protein intake appropriately, and ensure fresh vegetables, fruits and coarse grains every day; improve cooking methods, eat less pickled, smoked and fried foods, and do not eat moldy and burnt foods. Quit smoking and limit alcohol, avoid the use of excessive food additives, avoid food and drinking water pollution.
2.Enhance physical exercise, regular physical examination, timely treatment of precancerous lesions, and those with family genetic history should be monitored and followed up.
3, maintain a good mental state, adjust the mentality, and live a positive and optimistic life.