Rectal cancer

Introduction to rectal cancer Rectal cancer refers to cancer located between the dentate line to the sigmoid colon and the rectal junction. Is the common incidence of malignant tumors in the gastrointestinal tract after gastric and esophageal cancer is the most common part of colorectal cancer (accounting for about 60%). Most genetic patients account for more than 15% of men over 40 years old and under 30 years old. Seeing a male to female ratio of 2-3:1, rectal cancer is a lifestyle disease. At present, it has jumped to the second place in the cancer rankings, so diet, lifestyle, is the bane of cancer. basic knowledge Sickness ratio: 0.0001% Susceptible people: more common in men Mode of infection: non-infectious Complications: toxic shock syndrome

Rectal cancer etiology

Diet and carcinogens (20%):

Epidemiological studies have shown that the occurrence of colorectal cancer is clearly linked to economic status and dietary structure. High animal protein, high fat and low fiber diets are generally considered to be a major cause of colorectal cancer. Eat more fat, bile secretion, more bile acid decomposition products, intestinal anaerobic enzyme activity is also increased, resulting in intestinal carcinogen, increased carcinogen formation, easy to cause colorectal cancer. There are also studies that some of the ingredients in beer are a weak rectal cancer initiation or promotion factor, so beer is associated with the development of rectal cancer. In addition, factors such as insufficient vitamin intake and excessive consumption of fried foods may also be associated with the development of rectal cancer.

Rectal non-cancerous disease (15%):

Almost all rectal cancers have developed from polyps. Polyps originate in the inner or intestinal wall of the rectum, and these diseases evolve into cancer after years of prolongation. Certain types of polyps (inflammatory polyps) are not precancerous lesions, but adenomatous polyps can increase the risk of cancer, especially multiple or large polyps. Adenomas with high risk are considered to be large (>1 cm) tubular adenomas, multiple adenomas, adenomas with villi, and adenomas with poor differentiation. Chronic ulcerative colitis is closely related to colon cancer, but not closely related to the occurrence of rectal cancer.

Genetic factors (8%):

Epidemiological studies have confirmed that people with a family history of rectal cancer have a higher risk of rectal cancer than the general population. People with first-degree relatives with rectal cancer are twice as likely to develop the disease as the general population, and the age of the disease is obvious. in advance. Colorectal cancer caused by family genetic factors accounts for about 10%-20%. These genetic families are mainly familial adenomatous polyposis, Gardner syndrome family and Hereditary Nonpolyposis Colorectal Cancer (HNPCC). Also known as Lynch syndrome.

Other diseases (20%):

Some patients with chronic schistosomiasis were associated with colorectal cancer, but no significant correlation was found between the two.

Rectal cancer prevention

Since the etiology of rectal cancer is not completely clear, there are no special preventive measures so far. The preventive measures listed below are mainly to reduce the chance of cancer and early detection of patients and early treatment.

(1) Active prevention and treatment of rectal polyps, anal fistula, anal fissure, ulcerative colitis and chronic intestinal inflammation; for multiple polyps, papillary polyps, once diagnosed, should be surgically removed early to reduce the chance of cancer.

(2) Diet should be diversified, develop good eating habits, not partial eclipse, not picky eaters, do not eat high-fat, high-protein diet for a long time, and often eat fresh vegetables containing vitamins and cellulose, which may play an important role in preventing cancer. .

(3) Prevent constipation and keep the stool smooth.

(4) Attach great importance to regular anti-cancer census work, pay attention to self-examination at all times to improve vigilance, and find warning signal, timely diagnose and treat, so as to find early and early treatment to improve the survival rate of rectal cancer.

Rectal cancer complications Complications toxic shock syndrome

Colonic obstruction

It is one of the late complications of rectal cancer. It can occur suddenly or gradually. It is caused by tumor hyperplasia and obstruction of the intestine or intestinal lumen. It can also be caused by acute inflammation, congestion, edema and hemorrhage. Caused by.

2. Bowel perforation

There are two cases of rectal cancer with perforation: perforation occurs in the local part of the cancer; proximal colon perforation is a complication of cancer obstruction. After perforation, clinical manifestations of diffuse peritonitis, localized peritonitis or local abscess formation, diffuse Peritonitis is often accompanied by toxic shock and the mortality rate is extremely high.

The prognosis of rectal cancer has nothing to do with the gender and age of the patient, but it is closely related to the course of the disease, the extent of cancer invasion, the degree of differentiation and the presence or absence of metastasis.

Rectal cancer symptoms Common symptoms Weak rectal crisis diarrhea and constipation alternate rectal repeat deformity Fecal volume less anal pain cerebral palsy pain constipation pelvic cavity has a wider infiltration fulminant pain

The clinical features of early rectal cancer are mainly changes in blood in the stool and defecation. When the cancer is confined to the rectal mucosa, blood in the stool is the only early symptom, accounting for 85%. Unfortunately, it is often not taken seriously by patients. At that time, anal finger examination, more can touch the mass, in addition to the general common loss of appetite, weight loss, anemia and other systemic symptoms in the middle and late stage of rectal cancer, there are more frequent bowel movements, incomplete defecation, frequent intentions, urgency and other cancers Local irritation. Increased cancer can cause intestinal stenosis, signs of intestinal obstruction. Cancer invades surrounding tissues and organs, can cause dysuria, frequent urination, dysuria and other symptoms; invading the anterior tibial nerve plexus, appendix and lumbar pain; when transferred to the liver, causing hepatomegaly, ascites, jaundice, and even vaginal fluid Quality and other performance.

(1) Defecation habits change, bloody stools, pus and bloody stools, heavy and heavy, constipation, diarrhea, etc.

(B) the stool gradually thinning in the late stage, there is defecation obstruction weight loss or even dyscrasia.

(C) rectal examination: is the necessary examination steps for the diagnosis of rectal cancer. About 80% of rectal cancer patients can be diagnosed by the natural rectal examination at the time of treatment and found to be able to reach the hard and uneven bumps; late reachable intestinal stenosis The fixed fingertips of the mass are seen as dirty pus containing feces.

(D) rectal microscopy: can see the size and shape of the tumor and can directly take the interventional tissue for disease examination.

Rectal cancer screening

Rectal examination

(1) Position: generally use chest or knee position or stone removal position. Those with weak constitution use the left lateral position. These positions can touch the lesions 7 to 8 cm away from the anus. If necessary, the position can be used within 10 to 12 cm. Rectal lesions.

(2) Visual examination: Observe whether the anus is deformed, whether there is a lump, whether the skin has no nodules, ulcers, redness, fistula, etc.

(3) Advance finger: Apply finger oil on the fingertip sleeve, gently rub the anus with the finger to relax the anal sphincter. When the patient's anus is relaxed, gently put the finger into the anus and try to enter the deepest part.

(4) to understand the rectal anal canal mucosa: after the finger, check the surrounding wall of the rectal anal canal, and gradually withdraw the finger, pay attention to whether there are nodules, ulcers, stiffness, lump and tenderness.

(5) Palpation of the mass: if the mass is touched, the size, texture, activity, surface condition, the position on the intestinal wall, the distance from the anus, etc., such as the rectal anal canal stenosis caused by the tumor, should be known. When it cannot pass, it should not be forcibly broken. Generally speaking, the tumor from the outside of the rectum has a smooth surface mucosa. This is an important feature distinguishing between rectal tumors and extra-rectal tumors. At the same time, it should be noted that normal tissues such as the cervix and prostate are identified. Wait.

(6) Withdrawal: The finger should be checked for pustules and necrotic tissue.

It is a simple and easy method to diagnose exfoliated cells by rectal examination. For those with suspicious lesions, this test can be routinely performed. After the diagnosis, the stool or pus on the finger sleeves and mucus are directly applied to the mucus. Cytological examination on the glass piece, the positive rate can be more than 80%.

2. Sigmoidoscopy

If the rectal examination fails to reach the mass, and those who have suspected clinical symptoms or cannot exclude the tumor, further sigmoidoscopy must be performed. For rectal cancer, the general rigid sigmoidoscopy is sufficient, and the lesion can be directly seen under the microscope. The general form and the basis for obtaining living tissue specimens.

3. Gastroenterology contrast angiography

It helps to understand and rule out multiple tumors in the large intestine. The imaging findings of rectal cancer are:

1 nodular filling defect, mostly in the inner side wall of the rectum, round or smooth lobes, local intestinal wall stiffness, concave;

2 cauliflower-like masses, large, uneven surface, obvious lobes, wide bottom, and stiff intestinal wall;

3 irregular ring narrow, the wall is stiff, the mucous membrane is interrupted, and the boundary is clear;

4 Irregular intracavity shadows, triangles, strips, etc., shallower, uneven circumference around the ring;

5 complete intestinal obstruction, or signs of intussusception, obstruction of the proximal segment is sometimes difficult to display (Figure 4), it should be noted that X-ray examination of barium enema can not show rectal lesions, easy to make people produce the illusion of no disease.

4.B-ultrasound

For the case of rectal tumors, the B-ultrasound in the rectal cavity can be further developed. This is a non-invasive examination developed in recent years. The advantage is that it can judge the depth and extent of infiltration of rectal cancer, and it also has a certain value for whether the lymph nodes have metastasis. Liver B ultrasound is particularly important to prevent missed diagnosis of rectal cancer liver metastasis.

5.CT scan

The correctness of the depth of invasion in the intestinal wall is less than that of intracavitary ultrasound, but it has a higher diagnostic accuracy for moderate to extensive dissemination outside the intestine. Thoeni et al. (1981) suggested that the CT findings should be judged according to the following stages. : Stage I, intestine mass, no thickening of intestinal wall; stage II, intestinal mass with intestinal wall thickening >0.5cm, but not invading surrounding tissue; stage IIIa, tumor has invaded intestinal tissue, but The pelvic wall has not been invaded; in stage IIIb, the tumor has invaded the pelvic wall; in stage IV, the pelvic tumor with distant metastasis, the correctness of pelvic CT on the local dissemination of the tumor is 90%.

CT scan is of great significance for the monitoring of postoperative recurrence of rectal cancer. For patients who underwent Miles surgery, routine pelvic CT examination was performed once every 3 months after surgery. As a control for subsequent follow-up, if there were symptoms or reexamination, then pelvic cavity CT is compared with CT slices 3 months after surgery, so it is easier to find recurrent foci before sputum.

6. MRI examination

MRI can be used to examine the pelvic cavity from three orientations. It is ideal for displaying rectal cancer. On the T1-weighted image, the tumor has a soft tissue mass lower than or equal to the signal intensity of the intestinal wall tissue. The signal intensity of the tumor increases on the T2-weighted image, close to or Exceeding the signal intensity of adipose tissue, the thickness of the intestinal wall and the narrowing of the lumen are easy to find under the contrast of the gas in the intestine and the adipose tissue outside the intestinal wall. Axial scanning is beneficial to observe the relationship between the tumor and the intestine, sagittal and coronal. Scanning helps determine the extent, size, and effects of adjacent tumors and pelvic lymph node metastasis. Small infiltrate and rectal coils can be used to observe tumor invasion of the mucosa and submucosa.

7. Defecation angiography

When rectal cancer is associated with constipation symptoms, defecation angiography should be performed to show that the intestinal wall is stiff, filling, mucosal destruction, perineal decline and rectocele.

8. Pathological examination

  It is the main basis for the diagnosis of rectal cancer. Because rectal cancer surgery often involves diversion problems, affecting the quality of life of patients, in order to avoid misdiagnosis and mistreatment, preoperative or intraoperative must obtain the results of pathological examination to guide treatment, never dig easily In addition to the anus.

9. Carcinoembryonic antigen determination

The detection of carcinoembryonic antigen (CEA) has been widely carried out and is generally considered to be valuable for evaluating the therapeutic effect and prognosis. Continuous determination of serum CEA can be used to observe the effect of surgery or chemotherapy, and CEA is significantly reduced after surgery or chemotherapy, indicating that the treatment effect is good, such as Incomplete surgery or ineffective chemotherapy, serum CEA is often maintained at a high level, such as CEA decreased to normal and increased after surgery, often suggesting tumor recurrence.

Diagnosis and diagnosis of rectal cancer

The main basis for the diagnosis of rectal cancer

(1) Changes in bowel habits and nature.

(2) rectal examination and rectal examination well-known in the rectum, the endoplasmic hard irregular mass of the tissue taken deep into the disease can be confirmed.

Eating beneficial foods to prevent cancer may reduce the incidence of cancer itching by 30%-60%. It is very important to include alkaline foods such as fruits, vegetables and whole grains in the daily diet.

The diagnosis of this disease is not very difficult, about 75% of patients can only find the lesion through simple rectal examination, but the rate of misdiagnosis of rectal cancer is very high, the main reason is that the doctor ignored the rectal examination, based on the rectum Cancer is a common malignant tumor of the digestive tract, but it is easily misdiagnosed. The clinician should routinely perform digital rectal examination and sigmoidoscopy for each patient with blood in the stool, rectal irritation or bowel habit, and early detection of the lesion.

Differential diagnosis of colorectal cancer

1. The differential diagnosis of colon cancer is mainly colonic inflammatory diseases, such as intestinal tuberculosis, schistosomiasis, granuloma, amoebic granuloma, ulcerative colitis and colon polyposis. The clinical identification point is the length of the disease. Feces are examined for parasites, and the shape and extent of the lesions seen in the barium enema examination. The most reliable identification is biopsy by colonoscopy.

Abscess around the appendix can be misdiagnosed as cecal cancer (colon cancer), but the white blood sausage and neutrophils in the blood of this disease are increased, no anemia, weight loss and other cachexia, and the diagnosis of barium enema can be confirmed.

2. Rectal cancer is often misdiagnosed as sputum, bacterial dysentery, chronic colitis, etc., the rate of misdiagnosis is as high as 60% to 80%, the main reason is that no necessary examinations, especially anal and rectal examination.

3. Other tumors of the colon, such as colorectal carcinoid tumors, are asymptomatic when the tumor is small. When the tumor grows up, it can be ulcerated, and it appears as a symptom of colonic adenocarcinoma. The malignant lymphoma originating from the colon has a variety of lesions. It is often difficult to distinguish from colon cancer, and should be identified by tissue smear biopsy.

In the process of anorectal diagnosis and treatment, it is common to find a rectal extramucosal mass by fingering. Because the extramucosal mass is not as intuitive as rectal cancer, it is difficult to identify both benign and malignant, so it is often misdiagnosed. The origin of rectal extramucosal mass Complex, can come from the extramucosal wall tissue or extraintestinal tissue, according to the nature of the lesions can be divided into three categories:

1 benign tumors, such as leiomyoma, fibroids, etc.;

2 malignant tumors (including primary and metastatic), such as leiomyosarcoma, malignant lymphoma, teratoma, gastric cancer planting and transfer;

3 inflammatory mass or other benign hyperplasia, such as tissue-responsive hyperplasia or mechanization after acne injection treatment, tuberculous granuloma.

There are fewer common symptoms of rectal extramucosal mass, most of which are found in rectal perineal symptoms. These symptoms are very similar to rectal cancer, so if the results are simply confused with rectal cancer, especially Tumors break through the rectal mucosa, comprehensively ask the medical history, and help the diagnosis. The intracavitary B-ultrasound can determine the size and extent of the tumor, and it can also help to determine the source of the tumor. For larger tumors or tumors from the tibia, CT or MRI can be used. To understand the location and destruction of tumors, some tumors are derived from the metastasis of gastrointestinal tumors. Care should be taken to find primary lesions, such as gastroscopes, barium meal, etc., mass biopsy is the only means of diagnosis, biopsy should be performed under good anesthesia. Relax the anal sphincter, cut the mucosal layer, and cut the mass of the tumor under the vision. After a biopsy failure, it can be repeated many times. Most cases can be diagnosed.

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