colorectal tumor in the elderly
Introduction
Introduction to colorectal cancer in the elderly Colorectal cancer is a digestive tract malignant tumor originating from the rectum and colon. The incidence of colorectal cancer is rectal, sigmoid colon, cecum, ascending colon, descending colon, and transverse colon. The incidence increases with age. basic knowledge The proportion of illness: the incidence rate is about 0.004%-0.006% Susceptible people: the elderly Mode of infection: non-infectious Complications: intestinal obstruction, intussusception, peritonitis
Cause
The cause of colorectal cancer in the elderly
Genetic factors (20%):
The risk of total colorectal cancer is 1 in 50 in the general population, and the risk of cancer in the first generation of relatives is increased by 3 times to 1/17. If two of the first generation of relatives develop cancer, the risk rises to 1/6. Family heredity is more common in colon cancer than in rectal cancer.
Dietary factors (20%):
It is generally believed that high animal protein, high fat and low fiber diet are factors of high incidence of colorectal cancer, eating more fat, more bile secretion, followed by more bile acid decomposition products, intestinal anaerobic enzyme activity is also increased, and intestinal Endogenous carcinogens, increased carcinogen formation, leading to colorectal cancer, for example, anaerobic Clostridium can convert deoxycholate to 3-methylcholine, the latter has been shown to be a carcinogen.
Very common intestinal disease (10%):
It is estimated that 3% to 5% of ulcerative colitis occurs in colorectal cancer. The history of ulcerative colitis is 20 years, and the cancer is 12.5%. At 30 years, it is 40%. Some people think that 15% to 40% of colon cancer originates from Multiple polyps of the colon, the precancerous course is 5 to 20 years, the adenoma can be cancerous, the cancer rate is 0.9% in the diameter of 1cm, and the carcinogenesis is 12% in the diameter above 2.5cm. The more adenomas, the more cancerous opportunities, and the removal After recurrence and cancer, the colorectal adenoma in the middle age, after the elderly, must be actively treated to prevent the occurrence of colorectal cancer.
Parasitic diseases (20%):
According to Chinese data, 10.8% to 14.5% of advanced schistosomiasis lesions complicated with intestinal cancer. In Egypt, colorectal cancer combined with schistosomiasis accounted for 12.5% to 17.34%.
Other (10%):
For example, environmental factors are related to colorectal cancer, and there are many colorectal cancers in the molybdenum-deficient area, and there are many asbestos workers in colorectal cancer.
Pathogenesis
Colorectal cancer can occur in any part from the cecal to the rectum. The incidence of left colon in China is high, but it is also reported that the incidence of right colon cancer in women with high incidence is higher. According to the National Colorectal Cancer Pathology Research Group (NCG). The statistical data of 3147 cases of colorectal cancer, left spleen cancer and splenic spleen accounted for 82.0% of all colorectal cancer, of which the incidence of rectal cancer was the highest, accounting for 66.9%, significantly higher than Europe, America and Japan. The latter rectal cancer only accounts for 35% to 48% of colorectal cancer. The colorectal cancer in other intestinal segments is sigmoid colon (10.8%), cecum (6.5%), ascending colon (5.4%), transverse colon (3.5%). Colon (3.4%), hepatic flexion (2.7%), splenic flexion (0.9%).
Intestinal cancer can be divided into early cancer and advanced cancer according to the depth of tumor involvement. Early cancer refers to the large intestinal mucosa or submucosa, and no lymph node metastasis.
General type
(1) Early cancer:
1 polyp bulge type (type I) can be divided into pedicle type (IP), yati type (IS) or broad-based type, this type is also mostly intramucosal cancer.
2 flat type: This type is mostly intramucosal cancer.
3 flat bulge type (IIa) is generally divided into coins, this type involves the submucosa.
4 flat bulging ulcer type (IIa + IIc) is generally small disc-shaped, edge bulge, central depression, this type involves the submucosa.
(2) Middle and late stage colorectal cancer: For a long time, the general classification of colorectal cancer is quite confusing. In 1982, the Collaborative Group of Colorectal Cancer Research in China made a systematic and detailed observation on the surgical specimens of surgically resected colorectal cancer, and proposed the large intestine. The cancer is divided into four types and was adopted by the National Anti-Cancer Association in 1991.
1 bulge type: Where the main body of the tumor protrudes into the intestinal cavity, it is of this type, the tumor can be nodular, polypoid or cauliflower-like bulge, clear boundary, pedicle or broad-based, the tumor of the cut surface and the surrounding tissue often It is clear that the infiltration is superficial and limited. If the tumor surface is necrotic and falls off, ulcers may form.
2 Ulcer type: It is the most common type. The deep type of ulcer is formed in the center of this type of tumor. The bottom of the ulcer is deep or exceeds the muscle layer. According to the shape and growth of the ulcer, it can be divided into the following two subtypes:
A. Localized ulcer type: The ulcer has a crater-like appearance, and the central necrosis and depression form an irregular ulcer. The edge of the ulcer is a tumor tissue that is obviously bulged on the surface of the intestinal mucosa.
B. Infiltrating ulcer type: The appearance of this type of ulcer is like gastric ulcer. The tumor mainly infiltrates into the intestinal wall to thicken the intestinal wall, and then the central necrosis of the tumor forms a depressed ulcer. The ulcer is surrounded by the tumor tissue covered with intestinal mucosa. Slightly sloped ridges, cut surfaces, unclear tumor tissue boundaries, such as deep ulcers, local muscle layer can completely disappear.
3 Infiltrating type: This type of tumor is characterized by infiltration and growth in various layers of the intestinal wall. The intestinal wall of the lesion is thickened, the surface mucosa is thickened, irregular or disappeared, and there is no ulcer in the early stage. Shallow ulcer may appear in the later stage. .
4 gel-like type: When a large amount of mucus is formed in the tumor tissue, the tumor profile may be a translucent gelatinous shape, which is called a gel-like type. This type is found in mucinous adenocarcinoma, and the shape of the gel-like type is different, and it may have a bulge. It can also form ulcers or mainly infiltrates.
Among the above four general types, ulcer type is the most common. According to the pathological analysis of 3147 cases of colorectal cancer in China, ulcer type accounted for 51.2%, followed by uplift type 32.3%, infiltration type 10.1%, gel type 5.8%, general type and tumor. There is also a certain correlation between the occurrence of the tumor, the tumor of the right colon is more common with the type of swelling and localized ulcer, while the left colon cancer is more common with the infiltration type, and often leads to the annular narrowing of the intestine.
2. Type of histology
(1) Malignant tumors derived from glandular epithelium:
1 papillary adenocarcinoma: all or most of the tumor tissue is papillary, the nipple can be slender or thick and short, and the part of the infiltrating into the intestinal wall often shows that the nipple protrudes in the saccular gland of different sizes, usually The interstitial of the nipple is less, and the epithelium covered by the nipple surface is mostly a single layer or a stratified layer, and the degree of differentiation of the cancer cells is different.
2 tubular adenocarcinoma: is the most common histological type in colorectal cancer, accounting for 66.9%-82.1% of all colorectal cancer. Tubular adenocarcinoma is characterized by the formation of glandular tubular structure of cancerous tissue, according to the differentiation of cancer cells and glandular structures. And the degree of alienation can be divided into 3 levels:
A. well-differentiated adenocarcinoma: all or most of the cancerous tissue has a glandular tubular structure. The epithelial cells are more mature, and most of them are lining the glandular lumen. The nucleus is mostly located in the basal part, and there is secretion in the cytoplasm. Presenting goblet cell differentiation.
B. moderately differentiated adenocarcinoma: most of the cancerous tissues still have glandular tubular structures, but the glandular ducts are irregular in shape and vary in size and shape, or branched; a small number of tumor cells are arranged in solid nests or strips. The differentiation of cancer cells is poor: the abnormality is obvious. When the glandular structure is formed, the epithelium can be arranged into a pseudo-stratified layer. The nuclear position is uneven and overlapping, and can reach the cytoplasmic apex, and the cytoplasm secretory mucus is reduced.
C. Poorly differentiated adenocarcinoma: This type of tubular adenocarcinoma is characterized by inconspicuous glandular structure, and only a small part (1/3 or less) exhibits a glandular tubular structure, and the cell abnormality is more obvious.
3 Mucinous adenocarcinoma: This type of cancer is characterized by the secretion of a large amount of mucus by cancer cells and the formation of a mucus lake. Two types are often seen in histology: one is an enlarged cystic gland tubular structure, and the capsule is a large piece. Mucous epithelium, some of the epithelium is flattened by mucus in the capsule, and even disappears. Another histological manifestation is a large number of cancer cells floating in a mucus lake, with poor cell differentiation, large nuclear and deep staining. Can be printed in a ring shape.
4 signet ring cell carcinoma: the tumor consists of diffuse into a ring of sign ring cells, does not form a glandular tubular structure, when the mucus formation in the tumor cells is less, the nucleus can be round, the cytoplasm is pink stained and lacks the signet cell Characteristics, but mucus staining can detect mucus in the cytoplasm.
5 undifferentiated cancer: cancer cells are diffuse into pieces or in agglomerate invasive growth, do not form ducts or other tissue structures, cancer cells are usually small, cytoplasm is small, size and shape are more consistent, and sometimes difficult to distinguish from lymphosarcoma.
6 small cell carcinoma: about 0.5%, the cancer cells are small, slightly larger than lymphocytes, cancer cells are often arranged in close mosaic, cytoplasm is small, the nucleus is round, oval, melon-shaped or irregular, nucleus Deeply dyed, the nucleolus is unclear, and the degree of malignancy is high.
7 adenosquamous carcinoma: also known as adenoid cell carcinoma, adenocarcinoma and squamous cell carcinoma in such tumor cells are intermingled, adenocarcinoma is partially differentiated, generally better, with adenoid structure or more goblet cells and mucus Secretion, while the squamous cell carcinoma is generally poorly differentiated, and keratinization is rare.
8 squamous cell carcinoma: squamous cell carcinoma is the main component of colorectal cancer. If it occurs at the lower end of the rectum, it is necessary to rule out the possibility that the anal canal squamous cell carcinoma involves the rectum.
(2) Carcinoid: Colorectal carcinoid belongs to APUD tumor, which originates from neuroendocrine cells derived from neural crest. The early stage of carcinoid is mostly limited to the mucosa of the large intestine. It is a hemispherical nodular bulge on the surface of the mucosa. The cut surface is light brown and the border is thinner. Clear, no capsule, when the tumor volume increases more than 1 ~ 2cm, often invade the muscle layer or even the whole layer of the intestinal wall, histologically, the cancer-like cells are smaller, the cell size and shape are more consistent, and the nuclear chromatin particles are finer. The cytoplasm is less, lightly stained, and the other type is a typical carcinoid. The cells are arranged in an island shape, beam-like, strip-like, solid mass or daisy-shaped, and the interstitial is different, often showing hyaline degeneration. Most of the carcinoids of the large intestine belong to this type; the other type is glandular carcinoid, the cancer cells form gland, PAS-positive secretions can be seen in the cavity, and signet ring cells are sometimes seen. This type of carcinoid is rare, in addition, carcinoid Cells can secrete various hormones, such as 5-HT, ACTH, VIP, etc., and some patients may develop carcinoid syndrome.
The above histological typing has no important clinical significance. The biological behavior of carcinoids depends mainly on the size of the tumor and the depth of invasion. Carcinoids with a diameter greater than 2 cm or infiltrating into the muscular layer are usually regarded as malignant.
Prevention
Elderly colorectal cancer prevention
Third-level prevention
Colorectal cancer is the third leading cause of death in the world. Colorectal cancer in developed countries such as North America and Western Europe is the first or second largest in cancer death. In the mid-1970s, the standard mortality rate of colorectal cancer in China was male. It is 4.1/100,000, and women are 3.0/100,000, which are the 5th and 6th of all the causes of malignant tumors. However, the trend of the incidence of colorectal cancer in China has been remarkable in recent years. Take Shanghai as an example. Colorectal cancer only accounted for the sixth place in all malignant tumors. It has risen to the fourth place in the 1980s. Although the treatment of colorectal cancer has made great progress, the 5-year survival rate of advanced colorectal cancer has not changed much over the years. Therefore, the significance of prevention of colorectal cancer is more important. According to different interventions at different stages of the natural history of colorectal cancer, we can formulate the following prevention strategies.
Primary prevention: Eliminate or reduce the exposure of the large intestinal mucosa to carcinogens before the tumor occurs, inhibit or block the carcinogenesis of epithelial cells, thereby preventing the occurrence of tumors.
Primary prevention of colorectal cancer mainly includes lifestyle changes such as controlling fat intake, increasing fiber diet, actively preventing precancerous lesions such as vigorous prevention and treatment of schistosomiasis, radical colon and rectal adenoma and polyposis, and non-corticosteroid anti-inflammatory drug aspirin. Omega 3 unsaturated fatty acids, antioxidant vitamins C, E, calcium and vitamins have been used as chemopreventive agents in high-risk populations, but they are still in clinical research. The treatment of colorectal adenomas has received attention in recent years. 30% to 50% of cases are multiple adenomas. Therefore, if there is adenoma in the rectum and sigmoid colon, a full colonoscopy should be performed, and about 30% of patients may have a new gland after removal of the colorectal adenoma. Tumors, therefore, must be followed up regularly, studies of calcium ions can directly inhibit excessive proliferation of colorectal epithelial cells, may have the role of prevention of colorectal adenoma, colorectal cancer.
Secondary prevention: Screening for high-risk groups of colorectal cancer, in order to find asymptomatic preclinical tumor patients, to achieve early diagnosis, early treatment, improve patient survival rate, reduce population mortality, because screening can not only find early Colorectal cancer, can also be found in precancerous lesions of the colorectal cancer - adenomatous polyps, so that it can be treated in time to prevent the occurrence of cancer, in this sense, screening is a secondary prevention measure for colorectal cancer, but also Effective primary prevention measures.
At present, the most commonly used screening methods are anal digital examination, fecal occult blood test and sigmoidoscopy (SIG), while full colonoscopy and gas sputum double X-ray examination is complicated and expensive, mainly used for diagnostic examination and not as a screening method. .
(1) Anal examination: Anal examination is simple and easy, and can be found in the rectum within 8cm from the anus. 30% to 50% of the colorectal cancer in the country is within this range, but only 10% of the colorectal cancer in Europe and the United States can be used for anal diagnosis. Check it out.
(2) Fecal occult blood test: Intestinal non-dominant hemorrhage is the most common early symptom of colorectal cancer and colorectal adenoma. Since 1967 Greegor first screened colorectal cancer with fecal occult blood test, because of its economy, simplicity, safety, It is the most widely used screening method for colorectal cancer.
(3) Sigmoidoscopy: Gilbertsen began screening sigmoidoscopy for colorectal cancer and polyps in the early 1950s, and performed sigmoidoscopy on 85,487 people in 25 years. The American Cancer Society (ACS) guidelines for colorectal cancer screening guidelines Patients over the age of 50 should have a sigmoidoscopy every 3 to 5 years.
After the mid-1970s, fiber sigmoidoscopy gradually replaced hard mirrors. By 1992, 80% of family physicians in the United States had equipped and used 60cm fiber SIG. It is estimated that 35cm fiberscope can detect 40% of large intestine lesions, 60cm can be found 55 % of lesions.
Tertiary prevention: Active treatment of patients with clinical cancer to improve the quality of life and prolong survival.
2. Risk factors and interventions
Although the cause of colorectal cancer has been done in many countries around the world, it has not yet been fully elucidated. It is currently believed that it is closely related to environmental factors, and other factors also have an impact, which is the result of multiple factors.
(1) Environmental factors: Epidemiological studies have shown that about 70% to 90% of cancer incidences are related to environmental factors and lifestyles, and 40% to 60% of environmental factors are related to diet and nutrition to some extent. According to the survey, the high-risk countries have high-fat, high-animal protein, especially beef, less fiber and refined carbohydrates, which are the characteristics of the so-called Western diet, in which the effect of high-fat diet is most obvious, especially left. The incidence of semi-colon cancer is closely related. Population data show that vegetables can significantly reduce the risk of colorectal cancer. Fruit, vitamin E and certain minerals also have a certain effect on reducing the incidence of colorectal cancer.
(2) Genetic factors: Children with colorectal cancer have a 2 to 4 times higher risk of colorectal cancer than the general population. About 10% to 15% of colorectal cancer occurs in first-degree relatives (parents, brothers, sisters, children). In people with colorectal cancer, two hereditary syndromes of colorectal cancer have been identified: one is familial colorectal adenoma, the incidence rate is about 50% among children, and the large intestine begins when the patient is 5 to 10 years old. Adenoma occurs, if not treated, the cancer rate is high (about 50% at 20 years old, about 90% at 45 years old), the second is hereditary non-polyposis colorectal cancer, the incidence rate of first-degree relatives can be as high as 80%, accounting for 5% to 6% of all patients with large intestine, molecular level studies in recent years have also confirmed that the occurrence of colorectal cancer is related to the accumulation of genetic changes, the most common are: K-ras gene point mutation, growth inhibitory gene P53 mutation on chromosome 17P , allele loss on chromosome 5 (APC gene) and growth inhibitory gene DCC mutation on chromosome 18q, mutations in these genes are common in sporadic colorectal cancer.
(3) chronic inflammation of the large intestine: ulcerative colitis is most closely related to colorectal cancer, and the risk of colorectal cancer is 5 to 11 times higher than that of the same age group. Generally, cancer can occur after 10 years of illness, with age. Increasing, about 10% to 20% of cancer occurs every 10 years.
(4) colorectal adenoma: colorectal adenoma is closely related to colorectal cancer. It is generally believed that most patients with colorectal cancer have evolved through the stage of adenoma. It is undeniable that some patients directly undergo cancerous changes without undergoing adenoma stage. Clinically, The adenoma was found to be removed in time, and the incidence of colorectal cancer decreased. Multiple family polyposis is an autosomal dominant disease with about 50% of its children. If the patient is not treated in time and reasonable, 100 will be treated. % carcinogenesis, Gardner syndrome and Turcot syndrome are also hereditary diseases, less common than familial polyps, and the colorectal adenoma is prone to cancer.
(5) Others: The epidemic area of schistosomiasis is also a high incidence area of colorectal cancer. The colorectal cancer induced by schistosomiasis is mostly in the straight sigmoid colon, and the age of onset is earlier; radiation damage, ureteral sigmoid anastomosis and patients after cholecystectomy, colorectal cancer The rate is high.
3. Community intervention
The community should establish a medical system and network for the elderly, establish medical records for each elderly, conduct regular medical care lectures, guide the elderly to a reasonable diet, ensure nutrition, including trace elements in the diet, pay attention to physical exercise, and improve their immunity. Check the anus for 1 time, then occult blood 1 time, if there is abnormality, further check the fiber colonoscopy.
Complication
Elderly colorectal tumor complications Complications, intestinal obstruction, intussusception, peritonitis
Early intestinal obstruction, intussusception; advanced acute peritonitis, abdominal abscess, liver metastasis, bone metastasis, systemic failure, etc.
Symptom
Older colorectal cancer symptoms Common symptoms Abdominal pain, fatigue, inflammation, bowel habits, change, weight loss, constipation, anal pain, abdominal mass, weak stool
Colorectal cancer grows relatively slowly, with no obvious symptoms in the early stage, and sometimes can be asymptomatic for many years. Clinically, it is related to the location, size and secondary changes of the tumor.
The clinical symptoms of colorectal cancer are different in the anatomical and physiological functions of the left and right colon and rectum. Therefore, the symptoms after the tumor are different. The lumen of the left large intestine is not as wide as the right side, and the contents of the intestinal cavity are fixed. The pathological type of cancer is more common in invasive type, so the obstructive symptoms are more common than the right colorectal cancer, the right large intestine is relatively wide, the contents of the intestinal cavity are fluid, and the absorption function is strong. The clinical symptoms are poisoning symptoms and anemia. Abdominal mass, the frequency of clinical manifestations, right colon cancer in turn with abdominal mass, abdominal pain and anemia are most common, left colon cancer in order for blood, abdominal pain and frequent frequency are most common, rectal cancer in order Blood, frequent frequency and stool deformation are more common.
Blood in the stool
The surface of the tumor is different from the normal mucosa, and it is easy to bleed with the feces. The feces in the distal large intestine are relatively dry and hard, so the blood in the stool is more common. The left half of the large intestine has more bleeding, mostly for the blood of the naked eye. The rectal cancer is often caused by the surface of the tumor. Infection can have pus and bloody stools, while the right colonic stool is fluid, so the amount of bleeding is small, and due to the change in color in the stool, sometimes it is jam-like, and the blood is less common in the naked eye. Most patients are positive for occult blood.
2. Abdominal pain
Abdominal pain can occur early, the pain is easy to be neglected, the tumor site is strengthened by intestinal peristalsis, the tumor surface is increased by secretion and secondary inflammation is more irritating, causing abdominal pain, and the tumor grows to a considerable volume or infiltrate the intestinal wall to cause intestinal stenosis. Obstruction may occur paroxysmal abdominal cramps, accompanied by intestinal obstruction symptoms, anal pain can be caused by rectal cancer invasion of the anal canal, a small number of patients due to perforation of the tumor caused acute peritonitis, advanced patients invading the surrounding posterior abdominal wall can cause the corresponding parts Acute pain.
3. Changes in bowel habits
Often the earliest symptoms, the tumor itself secretes mucus and secondary inflammation changes not only increase mucus stools, but also stimulate bowel movements, increase the number of bowel movements, feces are not formed or loose stools, the lower the lesion, the more obvious the symptoms, before bowel movements Mild abdominal pain, the patient's symptoms are often misdiagnosed as enteritis and dysentery and delayed treatment. When mild intestinal obstruction is caused by the development of the lesion, loose stools and constipation alternate.
4. Abdominal mass
When some patients with colon cancer are diagnosed, they have already touched the abdominal mass. The malignant degree of colon cancer is lower than that of other gastrointestinal tumors. When the local growth reaches a considerable volume, there is no spread. If you ask the medical history carefully, you can find that the patient has had changes in bowel habits and abdominal pain. Symptoms, tumor penetration through the whole layer of intestinal secondary infection or tumor perforation caused by limited abscess, such as located in the cecum and ascending colon proximal, can be misdiagnosed as appendicitis abscess, should pay attention.
Anemia
The main cause of anemia is cancer hemorrhage, chronic blood loss, more common in right colon cancer, in the late stage of the disease, anemia and malnutrition and systemic consumption, the patient is accompanied by weight loss, hypoproteinemia and other debilitating performance.
6. Other
Tumor growth caused by intestinal stenosis or even complete blockage, can cause intestinal obstruction performance, about 10% of patients can be treated as acute intestinal obstruction, or although there are symptoms of chronic intestinal obstruction, but did not cause the patient to pay attention, the tumor invaded the surrounding organs Can cause internal hemorrhoids such as: stomach colon fistula, colonic bladder spasm, colonic vaginal fistula and cause the corresponding symptoms, acute perforation of tumor can cause acute peritoneal inflammation, tumor metastasis, the corresponding symptoms of metastatic sites.
In addition to systematic physical examination, the abdominal examination should pay more attention to the examination, including the presence or absence of abdominal distension, intestinal type and other signs of intestinal obstruction, palpation with or without mass, intestinal segment, suspicious colon tumor should be carefully examined on both sides of the ribs deep There are signs of hepatic spleen and spleen colon tumors, left and right lower abdomen and sigmoid colon masses, the possibility of colonic sputum and fecal mass should be ruled out.
Anal finger examination: Anal finger examination can detect the presence or absence of a lump, its size and surrounding conditions are fixed, the anal finger test mass is fixed and the pathological control can reach 75% to 80%, most of the pedicles do not penetrate the whole Intestinal layer, according to the examination, the subject should take different positions according to the examination. For example, the upper limb flexion, the supine stone position, the knee chest position and the ankle position are taken from the lateral position, and all the index fingers are extended into the rectum. Palpation, especially to pay attention to high polyps, the ratio of rectal cancer to colon cancer in China is 1.42:1, rectal cancer accounts for about 60% of colorectal cancer, rectal examination can generally understand the distance from the anus 7-8cm Lesions, about 70% to 80% of rectal cancer can be found through the anus.
Examine
Examination of colorectal cancer in the elderly
1. Fecal occult blood test
This method is simple and easy to perform, and can be used as an auxiliary examination for screening screening and diagnosis of colorectal cancer. There are various methods for detecting fecal occult blood in the clinic, such as chemical methods, immunological methods and monoclonal antibody technology, because of colorectal cancer, especially Early cancer bleeding is often intermittent, and the false negative results of various methods should be checked three times in a row, and the suspicious patients should be further examined by fiberoptic colonoscopy.
2. Carcinoembryonic antigen - CEA
Determination of serum carcinoembryonic antigen (CEA): In 1965, Gold extracted cell membrane glycoprotein from human colon cancer and pancreatic tissue, and found that it is also present in endoderm-derived digestive tract adenocarcinoma and 2-6 months embryo. In the liver, intestine and pancreas tissues, it is named CEA. The sensitivity and specificity of CEA for the diagnosis of colorectal cancer are not ideal. In addition to colorectal cancer, embryonic tumors, breast cancer, lung cancer and other non-intestinal tumors and some non- Tumorous diseases may have elevated serum CEA levels. A large number of clinical data indicate that serum CEA levels are positively correlated with lesion range, with certain false positives and false negatives. It is not suitable for census and early diagnosis, but for prognosis and monitoring. Efficacy and recurrence can be helpful. Preoperative CEA can predict prognosis. Patients with elevated CEA have a high recurrence rate. The prognosis is worse than that of normal CEA. The preoperative recurrence rate is 50%, and the normal CEA is 25%. Patients with pre-CEA increase should return to normal within 6 weeks or 1 to 4 months after radical surgery. Patients who remain high may still have residual tumors or predict recurrence. Dynamic observation often indicates preclinical recurrence or Residues, it is believed that CEA has increased 10 weeks to 13 months before the symptoms of recurrence, so those with increased CEA after radical surgery should be closely examined and followed up. If necessary, a second surgical exploration is required. CEA level In patients with elevated disease, a decrease in CEA levels after treatment indicates a good effect, whereas if CEA levels do not decrease or continue to increase, the effect is poor.
3. Other serum related antigen tests
The detection of serum CA19-9, CA242 and CA50 has been applied to colorectal cancer examination, and its sensitivity and specificity are not superior to CEA in clinical application of colorectal cancer.
4. Endoscopy
Includes colonoscopy, sigmoidoscopy, and fiberoptic colonoscopy.
(1) Proctoscopy: the rectal length is 15cm, and the rectal segment within 15cm, especially the lower rectum, is often difficult to find under the barium enema. Therefore, it is extremely important to perform colonoscopy on the rectal segment and it can be biopsied. Pathological examination, determine the type of tumor, proctoscopy is the most convenient, no need for intestinal preparation, can observe the location of the tumor, the scope of invasion, the distance between the tumor edge and the anal margin, for the lower rectal cancer, the pathological diagnosis can be performed before the abdominal perineal joint Radical surgery.
(2) Colonoscopy: sigmoidoscopy can examine all rectum and part of sigmoid colon within 25cm from the anal verge. Only the lower large intestine needs to be cleaned. 60%~70% of patients with colorectal cancer can be found, and colon cancer is more than 25cm away from the anal margin. At present, fiberoptic colonoscopy is the most reliable method of examination, but it requires bowel preparation, and the doctor is skilled in operation. Endoscopy can directly observe the lesion and take the living tissue for pathological diagnosis. When taking the biopsy, pay attention to the material to be taken. If the biopsy negative clinical consideration is a tumor patient, the material should be repeated to avoid missed diagnosis. Missed diagnosis is sometimes more serious than the unchecked result. At the current level, fiberoptic colonoscopy is still the most effective, safest and most reliable for the diagnosis of colorectal cancer. Intra-rectal endoscopic ultrasonography can understand the depth of tumor invasion and invasion of surrounding tissues, and can find lymph node metastasis in the pelvic cavity, provide a basis for the choice of anal sphincter surgery for lower rectal cancer, three-dimensional rectal endoscopy not only improved The accuracy of two-dimensional intracavitary ultrasound, and the understanding of tumor invasion in patients with obstruction Conditions.
5. Imaging examination
The purpose of imaging examination is to detect infiltration and metastasis in addition to lesions in the intestine. The estimation of infiltration depth is extremely important. Currently, the commonly used imaging methods include X-ray barium enema examination, CT, MRI, and rectal cavity B-ultrasound ( IUS).
(1) X-ray examination: X-ray examination is the most common and effective method for diagnosing colorectal cancer. At present, double contrast angiography of colon is the first choice for diagnosis of colorectal cancer. It can provide the location, size, shape and type of colorectal cancer, colorectal cancer. The performance of barium enema is related to the general morphology of the cancer. It is mainly characterized by the disappearance of colonic pouch in the lesion, filling defect, intestinal stenosis, mucosal disorder and destruction, ulcer formation, intestinal wall stiffness, multiple lesions, clear boundary with normal part, and uplift. The type is more common in the cecum. It is mainly characterized by filling defects and soft tissue masses. It is lobulated or cauliflower-like surface irregular. The ulcer type is irregular filling defect and intracavitary sacral shadow. The surrounding mucosal folds are disordered, irregularly damaged, and infiltrating. The most common cancer is found in the left colon. The intestine is concentric or eccentric stenosis, and the intestinal wall is thickened. Due to the imbalance of tumor growth, the stenosis is uneven and the boundary between the lesion and the intestine is clear.
(2) computed tomography imaging (CT): observation of morphological changes in the colon cavity, general gastroenterology enema examination is better than CT, but CT is helpful to understand the degree of cancer invasion, CT can observe the thickening of the intestinal wall Outstanding, but sometimes it is difficult to identify benign and malignant in the early stage. The biggest advantage of CT is to show the involvement of adjacent tissues, lymph node or distant organs with or without metastasis, so it is helpful for clinical stage. CT manifestation of colorectal cancer is local intestinal wall enlargement. Thick, showing a mass growing into the cavity, or in a ring shape, thickening of the semicircular intestinal wall, irregular outer wall of the intestinal wall when the tumor is invaded, and the fat layer disappears with the surrounding organs, suggesting that the cancer has infiltrated the adjacent organs. Rectal cancer can invade the prostate, seminal vesicle, vagina or bladder, sciatic rectal fossa and anterior or tibia. CT provides a reasonable treatment plan for preoperative understanding of whether there is any metastasis in the liver before surgery, whether the abdominal aortic lymph nodes are swollen or not. More reliable basis.
(3) MRI (magnetic resonance imaging) examination: MRI has a high contrast resolution, clearly showing the soft tissue structure of the basin and the adjacent relationship of the organs. It has a certain effect on the preoperative staging of rectal cancer and guiding the choice of surgical plan, just like CT examination. It can also be used to detect liver metastasis and lymph node metastasis adjacent to the abdominal aorta, but it is difficult to identify lymphatic metastasis.
(4) Ultrasound examination of type B: The sonographic image of colon cancer is characterized by a hypoechoic mass containing a strong echogenic core, a low echo representing a mass, and a strong echo representing the intestinal lumen. The "false kidney sign" is a typical ultrasound manifestation of colon cancer, rectum Intracavitary ultrasound can determine the depth of tumor infiltration, the presence or absence of metastasis of surrounding lymph nodes, the effect is significantly better than CT and MRI, for patients with low early rectal cancer to choose anal surgery can be performed intracavitary ultrasonography, strict screening for suitable cases.
6. Nuclide check
The use of radionuclides for colorectal cancer includes:
(1) Serological correlations such as CEA, AFP, CA-50, CA-119 and the like are determined by serology.
(2) The radionuclide diagnosis for in vivo localization, from the accumulation status of a specific radionuclide substance to determine the location or size of the primary or metastatic tumor, 67Ga-citrate is commonly used, 74185MBq (25mci, 74) 165mEq, intravenous injection), after 24 to 96h, OTO camera or ECT for imaging of the lesion site (ECT), radioactive accumulation of cancer, but in the normal area around the bone, liver, and large joints can also accumulate 67Ga In the case of a false positive, 131I is often injected into the body with a labeled CEA to detect the lesion.
7. Cell and histological diagnosis
The method of exfoliative cytology of colorectal cancer includes rectal rinsing, brushing under direct vision of the colonoscopy, airbag wiping in the wire mesh, and finger smear method at the lesion. If malignant cells are found, it is diagnostic, but not enough for final diagnosis. The diagnosis is still based on histopathology.
8. New ideas, new concepts
With the research of molecular genetics of tumors, the development and application of in vitro gene amplification technology polymerase chain reaction (PCR) has provided a possibility for tumor gene diagnosis. Currently, there are polymerase chain reaction-limited fragments. The length polymorphism analysis (PCR-RFLP) method detects single-molecule DNA or a sample containing only one target DNA molecule per 100,000 cells.
(1) Determination of the mutation rate of ki-Ras gene in colorectal cancer and adjacent tissues helps to understand the degree of malignancy of the tumor, and provides a reference for predicting the prognosis. There are many human tumors in the Ras gene, which is a potential tumor marker and a single point mutation. The Ras gene can be turned into an oncogene, and the dry moon wave can detect the 12th codon mutation in 11 cases (31.4%) in 35 cases of colorectal cancer in China, and 61 cases (2.9%) in 61 cases, only 1 case. The 12th codon of the paracancerous tissue was mutated, and the 13th codon GlyAsp mutation, which is more common in western colorectal cancer, was not found.
(2) Detection of mutant ki-Ras gene in feces, Vgeolekin et al. Examination of 24 suspected colorectal cancer stools, 9 cases of RaS gene, and 8 cases of mutations. This test method can be used for people who are highly suspicious and cannot be found by general methods. Monitoring has practical application prospects for early detection of colorectal cancer.
Diagnosis
Diagnosis and diagnosis of colorectal tumors in the elderly
Differential diagnosis:
Appendicitis
Cecal cancer often has right lower quadrant pain and right lower quadrant mass, and often fever, easily misdiagnosed as appendicitis or appendix abscess, misdiagnosis rate of 25%, combined with medical history and barium enema X-ray examination can often be diagnosed, if not identified, should be surgery Exploring is appropriate.
2. Gastrointestinal ulcer, cholecystitis
Right colon cancer, especially hepatic colitis, transverse colon cancer causes upper abdominal discomfort or pain, fever, fecal occult blood test, right upper abdomen mass, etc., sometimes misdiagnosed as ulcer disease, cholecystitis, but combined with medical history and X-ray examination, diagnosis Not difficult.
3. Colon tuberculosis, dysentery
Left colon or rectal cancer often has mucous blood or pus and bloody stools, frequent stools or diarrhea, often misdiagnosed as colitis, and it is not difficult to diagnose by sigmoidoscopy and careful physical examination.
4.
Symptoms of internal hemorrhoids are painless hemorrhage, which may be blood in the feces, blood in the anus or linear bleeding. Patients with rectal cancer also have blood in the stool, but often have anal rectal irritation at the time of treatment. The two are extremely easy to identify, anorectal Finger test or proctoscopy will be seen.
5. Anal fistula
Anal fistula usually has an anal abscess first, starting with local pain, ulceration after abscessation, symptom relief, bowel habits and stool properties without rectal cancer or anal canal cancer.
