I. Overview
The incidence and mortality rate of colorectal cancer (CRC) in China have been on the rise. 2011 incidence and mortality rates of colorectal cancer were 23.03 per 100,000 and 11.11 per 100,000, respectively.) Among them, the incidence rate of colorectal cancer is much higher in urban areas than in rural areas, and the incidence rate of colorectal cancer has increased significantly. Most patients are already in the middle and late stages when they are found.
In order to further regulate the diagnosis and treatment behavior of colorectal cancer in China, improve the diagnosis and treatment level of colorectal cancer in medical institutions, improve the prognosis of colorectal cancer patients, and guarantee medical quality and medical safety, this specification is formulated.
Diagnostic techniques and applications
(I) Clinical manifestations.
Early colorectal cancer may have no obvious symptoms, but the following symptoms may appear when the disease has developed to a certain extent.
1. Change in bowel habit.
2. Change in stool characteristics (thinning, bloody stool, mucus stool, etc.).
3, abdominal pain or abdominal discomfort.
4. Abdominal masses.
5.Symptoms related to intestinal obstruction.
6, anemia and systemic symptoms: such as wasting, weakness, low fever, etc.
(II) Disease history and family history
1. The development of colorectal cancer may be related to the following diseases: ulcerative colitis, colorectal polyposis, colorectal adenoma, Crohn’s disease, schistosomiasis, etc. Patients should be asked about the relevant medical history in detail.
The incidence of hereditary colorectal cancer accounts for about 6% of the overall incidence of colorectal cancer, and patients should be asked about their family history: hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, melanotic polyp syndrome, juvenile polyposis.
(C) Physical examination.
1.General condition evaluation, general superficial lymph node condition.
2.Abdominal visual examination and palpation, check whether there is intestinal pattern, intestinal peristaltic wave, abdominal mass.
3.Rectal finger examination: all suspected colorectal cancer patients must routinely undergo anorectal finger examination.
To understand the size, texture, circumference of the intestinal wall, basal mobility, distance from the anal verge, infiltration of the tumor to the outside of the intestine, relationship with the surrounding organs and the presence of pelvic floor implantation. During finger examination, we must touch carefully to avoid missing diagnosis; touch gently, avoid squeezing, and observe whether the finger stains with blood.
(iv) Laboratory tests.
1.Blood routine: to know whether there is anemia.
2.Urinary routine: Observe whether there is hematuria, combine with urinary imaging to understand whether the tumor invades the urinary system.
3.Fecal routine: pay attention to the presence of red blood cells and pus cells.
4.Fecal occult blood test: It is important for the diagnosis of small amount of bleeding in the gastrointestinal tract.
5.Biochemistry and liver function.
6.Patients with colorectal cancer must be tested for CEA and CA19-9 before diagnosis, treatment, evaluation of efficacy and follow-up; patients with liver metastases are recommended to be tested for AFP; patients with suspected ovarian metastases are recommended to be tested for CA125.
(v) Endoscopy.
Proctoscopy and sigmoidoscopy are indicated for colorectal lesions with low lesion location. Colonoscopy is recommended for all patients with suspected colorectal cancer, with the following exceptions.
1, poor general condition, difficult to tolerate;
2.Acute peritonitis, intestinal perforation, extensive adhesions in the abdominal cavity;
3.perianal or serious intestinal infection;
4, women during pregnancy and menstruation.
The endoscopy report must include: depth of entry, size of the mass, location from the anal verge, morphology, and the extent of local infiltration, and pathological biopsy must be performed for suspicious lesions.
Since the colon canal may be crinkled during the examination, the distal distance of the mass from the anal verge seen by endoscopy may be inaccurate, and it is recommended to combine CT, MRI
or barium enema to clarify the site of the lesion.
(vi) Imaging examination.
1.Barium enema examination of colon, especially the air-barium double contrast examination is an important means to diagnose colorectal cancer. However, patients suspected to have intestinal obstruction should be selected with caution.
2.B-type ultrasound: abdominal ultrasound examination can understand whether the patient has recurrence and metastasis, and has the superiority of convenience and speed.
3.CT examination: The function of CT examination is to clarify the depth of lesion invasion to the intestinal wall, the extent of extra-mural spread and the distant metastasis site. At present, CT examination of colorectal cancer is recommended for the following aspects.
(1) providing the staging of colorectal malignancies.
(2) To detect recurrent tumors.
(3) To evaluate the response of tumors to various treatments.
(4) To elucidate the internal structure and clarify the nature of intrinsic and extrinsic compressive lesions in the intestinal wall found by barium enema or endoscopy.
(5) To evaluate intra-abdominal masses found by barium enema and to clarify the origin of the masses and their relationship to the surrounding organs.
(6) It can determine the location of the tumor.
4.MRI examination: The indications of MRI examination are the same as CT examination. MRI is recommended as routine examination items for rectal cancer.
(1) Preoperative staging of rectal cancer.
(2) Evaluation of liver metastasis lesions of colorectal cancer.
(3) Suspected peritoneal and subhepatic lesions.
5.Transrectal endoluminal ultrasonography: endoluminal ultrasonography or endoscopic ultrasonography is recommended as a routine examination for the diagnosis and staging of middle and low rectal cancer.
6.PET-CT.
PET-CT is not recommended for routine use, but it can be used as a routine test for patients with complicated conditions and whose diagnosis cannot be made clearly by routine examination.
PET-CT is not recommended for routine use, but it can be used as an effective adjuvant examination for patients with complex disease and cannot be diagnosed clearly by conventional examination. PET-CT is not recommended for routine use, but it can be used as an effective auxiliary test for patients with complicated disease and cannot be diagnosed clearly by conventional examination.
7. Excretory urography: It is not recommended as a routine preoperative examination and is only applicable to patients with large tumors that may invade the urinary tract.
(vii) Pathological histological examination.
Pathological biopsy to clarify the nature of occupancy is the basis of colorectal cancer treatment. Cases diagnosed as invasive carcinoma on biopsy are treated with standardized colorectal cancer treatment. If the depth of infiltration cannot be determined by biopsy pathology due to the limitation of biopsy sampling, cases diagnosed as high-grade intraepithelial neoplasia, clinicians are advised to determine the treatment plan by integrating other clinical conditions including the presence or absence of choroidal carcinoma emboli and lymphocytic reaction around the cancer. When recurrent or metastatic colorectal cancer is identified, testing of tumor tissue Ras gene and other related gene status is recommended to guide further treatment.
(viii) Open or laparoscopic exploratory surgery. Open or laparoscopic exploration is recommended for the following cases.
1. Colorectal tumor is not clearly diagnosed by various diagnostic means and is highly suspected.
2.Intestinal obstruction and conservative treatment is ineffective.
3.Suspected intestinal perforation.
4.Lower gastrointestinal hemorrhage for which conservative treatment is ineffective.
(ix) Diagnostic steps of colorectal cancer.
The diagnostic steps of colorectal cancer are shown in Figure 1.
cTNM staging is recommended after diagnosis.