I. Scope
This guideline specifies the standardized diagnosis and treatment process, diagnostic basis, diagnosis, differential diagnosis, treatment principles and treatment plan of colorectal cancer.
This guideline applies to the diagnosis and treatment of colorectal cancer in municipal and county-level pilot hospitals with corresponding qualifications for standardized diagnosis and treatment of common tumors and their medical personnel.
II. Terms and definitions
Rectal mesentery: It refers to the connective tissue that forms a semicircle 1,5~2,0cm thick and contains arteries, veins, lymphatic tissues and a large amount of fatty tissues wrapped around the rectum at the back and sides of the middle and lower rectum, up from the front of the 3rd sacral vertebra and down to the pelvic diaphragm.
Abbreviations
The following abbreviations apply to this guideline
TME: (total mesorectalexcision) total rectal mesenteric resection
CEA: (cancinoembryonicantigen) carcinoembryonic antigen
IV. Standardized diagnosis process
V. Colon cancer treatment process
VI. Diagnostic basis
(I) High risk group
People with intestinal symptoms such as blood in stool, frequent stool, mucus in stool and abdominal pain; middle-aged and elderly people in areas with high incidence of colorectal cancer; patients with colorectal adenoma; people with history of colorectal cancer; family members of patients with colorectal cancer; familial colorectal adenomatosis; ulcerative colitis; Crohn’s disease; people with history of pelvic radiation therapy.
(B) Clinical manifestations and signs
The frequency of clinical manifestations of right-sided colon cancer is most common in the order of abdominal mass, abdominal pain and anemia. Left-sided colon cancer is most common in the order of blood, abdominal pain and frequent stools. Rectal cancer is most common in the order of blood, frequent stool and stool deformation.
1.Right-sided colon cancer
Clinically, it often manifests as unexplained anemia, weakness, emaciation and low fever. In the early stage, there is occasional abdominal pain and discomfort, and in the later stage, a hard mass can be found in the right side of the abdomen in 60% to 70% of patients.
2.Left-sided colon cancer
In the early stage, it can be manifested as change of bowel habit, such as frequent stool, constipation or alternating between frequent stool and constipation. Tumor growth may cause narrowing or even complete obstruction of the lumen, which may lead to intestinal obstruction, and about 10% of patients may show symptoms of acute intestinal obstruction or chronic intestinal obstruction.
3.Symptoms of rectal irritation
Frequent stool, urgency and heaviness, anal drop, feeling of incomplete stool, anal pain, etc. Blood and/or mucus on the surface of stool, or in severe cases, pus and blood stool.
4. Rectal examination
Any patient with symptoms such as blood in stool, rectal irritation and deformation of stool should undergo rectal finger diagnosis. The examination should be gentle and should not be rough, paying attention to the distance of the tumor from the anus, size, hardness, mobility, smoothness of the mucous membrane, pressure pain and relationship with surrounding tissues, whether it invades the pre-sacral tissue. If the tumor is located in the anterior wall, the relationship with prostate gland must be clarified in men, and female patients need to do vaginal finger diagnosis to find out whether it invades the posterior vaginal wall. If the tumor is located in the anterior wall, the relationship with the prostate must be clarified in men.
(C) Auxiliary examination
1.Fiber colonoscopy
It is the most effective, safe and reliable examination method to diagnose colon cancer. Fiberscopic colonoscopy can directly observe the lesion and take biopsy for pathological diagnosis. When taking biopsy, we need to pay attention to the sampling site and make multi-point sampling. If the biopsy is negative and the patient is clinically considered to be a tumor, the biopsy should be repeated to avoid missing the diagnosis.
2.X-ray examination
Double contrast radiography is a common and effective method to diagnose colon cancer. It can provide the location, size, shape and type of colon cancer lesions. The performance of barium enema of colon cancer is related to the general morphology of cancer, which mainly shows disappearance of colonic pouch, filling defect, lumen narrowing, mucosal disorder and destruction, ulcer formation, rigid intestinal wall, and the lesion is mostly limited and clearly demarcated from normal intestinal canal. The augmented type is mostly seen in the cecum and mainly manifests as filling defects and soft tissue masses with a lobulated or cauliflower-shaped surface irregularity. Ulcerated type shows irregular filling defect and intra-luminal niche shadow, disorganized surrounding mucosal folds and irregular destruction. Infiltrating type cancer is mostly seen in the left colon, with centripetal or eccentric stenosis of intestinal canal, thickening of intestinal wall and uneven height due to unbalanced tumor growth and stenosis.
3.B-type ultrasonic examination
B-type long life scan of abdomen in colon cancer has certain value to determine whether there is metastasis in liver, so it should be listed as one of the contents of routine preoperative examination.
4.CT scan examination
CT examination of abdominopelvic cavity should be a routine examination item, which provides a more reliable basis for preoperative understanding of whether there is metastasis in liver, whether there is enlargement of lymph nodes beside abdominal aorta, whether there is infiltration of cancer into surrounding structures or organs, judging the possibility and risk of surgical resection, etc. to guide the selection of reasonable treatment plan before surgery.
5.Chest X-ray examination
It should include frontal and lateral chest X-ray to exclude lung metastasis.
6.Laboratory examination
(1) Fecal occult blood test: this method is simple and easy to use, and can be used as the initial screening method and diagnostic auxiliary test for colon cancer screening.
(2) Serum tumor markers, serum CEA level is positively correlated with lesion scope, with certain false positives and false negatives, not suitable for screening and early diagnosis, but it is helpful for estimating prognosis, monitoring treatment effect and recurrence.
VII. Classification and staging of colorectal cancer