How to detect colorectal cancer early---public welfare science of digestive diseases
2015-03-20 Gastroenterology popular science Gastroenterological popular science
With the improvement of people's health awareness, many middle-aged and elderly people will regularly do routine physical examinations including blood tests, abdominal B-ultrasound, chest X-ray, but few people take the initiative to do intestinal health examinations.
Colorectal cancer is a preventable and curable malignant tumor. Due to the effectiveness of preventive measures and health education, the incidence and mortality of colorectal cancer in the United States are currently in a declining stage; while the incidence and mortality of colorectal cancer in China are in a rapid increase stage.
The symptoms of colorectal cancer (i.e. colorectal cancer) are relatively insidious. In the early stage of the disease, or even in the late stage of the disease, patients may have no obvious local symptoms, so that many patients have reached the middle and late stage at the time of diagnosis, and the treatment effect is greatly reduced. Therefore, the intestinal health check is particularly important.
However, early colorectal cancer has no specific symptoms. How should colorectal cancer be detected early through physical examination?
1. Digital rectal examination
Doctors can judge anorectal diseases through the simplest and direct palpation and observation. More than half of colorectal cancers occur in the rectum, and 80% of rectal cancers are in the low-to-medium position. Digital rectal and anus examinations can be found. For perianal diseases and colorectal cancers Make a preliminary judgment.
The rectum of an adult is generally 15 cm long, and the rectal wall below 7-8 cm from the anal opening can be directly touched with hands. A slightly raised nodule can be found on the rectal mucosa. Of the colorectal cancer patients in China, more than half are rectal cancer, and among the rectal cancer patients, about 60-70% are middle and low rectal cancer. In other words, 70% of rectal cancers (about one-third of colorectal cancers) can be detected by digital anal examination. If the doctor finds mucus on the finger cuff during the examination, it means that the patient has purulent secretions in the rectum. If it is stained with dark red blood, it may indicate intestinal bleeding, and bright red may be bleeding from hemorrhoids. Most rectal cancers, especially low rectal cancers, can be found through digital rectal examination. In addition, the shape, texture, and mobility of the cancer can be clarified through digital rectal examination.
2. Fecal occult blood test
Fecal occult blood test is of great value in the diagnosis of gastrointestinal bleeding, and is often used as a screening indicator for early diagnosis of gastrointestinal malignancies.
Why do an occult blood test to screen for colorectal cancer: When there is a small amount of bleeding in the digestive tract, there will generally be no symptoms such as blood in the stool or melena. The appearance of the stool is not abnormal to the naked eye, but the fecal occult blood test can be used to judge a very small amount of bleeding in the digestive tract. In fact, it is not only colorectal cancer, including gastric cancer and other gastrointestinal tumors. In the early stage of tumor occurrence, the tumor will erode the mucosa and submucosal blood vessels and cause a very small amount of gastrointestinal bleeding. Such a small amount of bleeding is difficult to judge with the naked eye. The stool examination revealed whether there was any hidden gastrointestinal bleeding. For people who have no history of gastric disease, if the fecal occult blood test is found to be positive on the physical examination, it is recommended to do it again at a certain time. If it still or continues to be positive, then you need to be vigilant. First, you must exclude digestive tumors. The most common gastrointestinal tumors are stomach, Colon, duodenum, colonoscopy or gastroscopy should be performed on the recommendation of a specialist. (Attachment: fecal occult blood test is positive: it is intermittently positive in the case of gastrointestinal ulcer bleeding; and gastrointestinal tumors are often persistently positive, so it can be used as a distinction between benign and malignant bleeding.)
After the age of 40, the risk of colorectal cancer will increase significantly. According to statistics, about 75% of colorectal cancer patients are in this age group. Therefore, people should do a stool occult blood test every year from the age of 40 to be wary of bleeding caused by polyps or tumors. First of all, the stool occult blood test is more convenient than colonoscopy and anal examination, and it is easier to perform screening. About ten yuan.
Colonoscopy is the most effective way to detect early colorectal cancer. Colonoscopy can not only clearly observe the intestines, but also clamp suspicious lesions under direct vision for pathological examination, which is conducive to the detection and diagnosis of early and small colorectal cancer.
At present, few people take the initiative to do colonoscopy health examinations. There are two main reasons: one is the lack of awareness of colorectal cancer, and the other is that the people are difficult to accept and even fear the invasive examination method of colonoscopy. This kind of fear has delayed the condition of many patients, resulting in the failure of early diagnosis and treatment of many colorectal cancer cases in clinical practice, and missed treatment opportunities.
With the development of medical technology and the improvement of doctors' operating proficiency, the discomfort of colonoscopy has been greatly reduced, and the examination time has been greatly shortened. It takes about a quarter of an hour to complete a colonoscopy. In addition, you can also choose to perform painless colonoscopy under intravenous anesthesia.
Another great significance of colonoscopy is that it can find and minimally invasively treat colon polyps, especially adenomatous polyps and other precancerous lesions. We know that most colorectal cancers are derived from adenomas. From the onset of adenoma to the onset of cancer, it may take several years or even longer. For example, when the adenoma is not cancerous or early cancerous, it can be found through colonoscopy and treated with minimally invasive endoscopy. , It can block its chance of transforming into cancer.
To strengthen the screening of high-risk populations. In theory, half of the children of family colonic polyposis patients will suffer from colonic polyposis, and they will inherit the disease in their offspring. Therefore, screening should be strengthened for high-risk populations who are prone to colorectal cancer, and the screening targets are mainly the following types of people;
1. If one of the parents, siblings and children has colorectal cancer, stool occult blood test and colonoscopy should be done from the age of 40.
2. People who have family adenomatous polyps are because of defects in related genes. Almost all patients with this disease will develop colon cancer after the age of 40. Therefore, all members of such families should undergo regular colonoscopy from their teenage years.
3. Patients with ulcerative colitis are at greater risk of colorectal cancer. This risk usually starts 8 years after the onset of the patient. Therefore, patients with pancolitis should undergo colonoscopy every 1-2 years after 8 years of illness. Patients with left hemicolitis should undergo colonoscopy every 1-2 years after 15 years of illness.
4. In the past, it was believed that the polyps of patients with black spot polyposis would not become cancerous. However, clinical data in recent years show that the probability of malignant transformation of black spot polyposis is 20%-23%. Therefore, patients with black spot polyposis should also be checked regularly.
Colorectal cancer mainly includes colon cancer and rectal cancer. In recent years, the incidence of colorectal cancer in China has been increasing year by year, and patients with colorectal cancer that can be diagnosed early account for only 5% of all patients with the disease. Clinically, the early diagnosis rate of colorectal cancer is low. The main reason is that people do not pay enough attention to the early signs of the disease.
Colorectal cancer is a curable disease
In the past ten years, with the continuous development of science, the diagnosis and treatment of colorectal cancer have made significant progress. The biological characteristics of colorectal cancer and the genetic mechanisms involved in tumorigenesis are better understood. Therefore, people can find the lesions earlier, and can use molecular genetic monitoring to establish a more complete staging system; improve surgical techniques to reduce postoperative mortality and recurrence; at the same time, the emergence of efficient treatment drugs makes colorectal cancer treatment options Constantly updated, therefore, patients have a longer survival period, a higher quality of life, and even early patients can be cured. Therefore, tumor treatment emphasizes the word "early", early detection, early diagnosis, and early treatment
The general population: refers to people who are not at high risk of colorectal cancer. We recommend that these people start to receive colorectal cancer screening after the age of 45. An average check is performed every 5-10 years. The inspection methods mainly include fecal occult blood and colonoscopy. For high-risk populations, excluding those with family genetic history, we recommend that you start screening for colorectal cancer at around 40 years old, with an average of 3-5 years.
People with family genetic history: For people with family genetic history, we recommend that you go to a large cancer center as soon as possible, through careful collection of family history by experienced clinicians and some necessary examinations, including genetic testing, to judge Whether this population has a genetic predisposition. If there is a genetic predisposition, the clinician will follow up closely according to the follow-up plan for specific hereditary tumors. If there is no obvious genetic predisposition, follow up according to the screening plan for high-risk groups.
Stool occult blood test and digital anal examination can be used as a general screening method for colorectal cancer, which can provide clues for early diagnosis. It is recommended to check once a year. Before colonoscopy is not popular, fecal occult blood test and digital anal examination are good supplements.