Auxiliary examination of diagnosis and treatment norms for gastric cancer

(1) Gastroscopy: a necessary means to diagnose gastric cancer, which can locate the tumor and obtain tissue samples for pathological examination. Pigment endoscope or magnifying endoscope can be selected as appropriate when necessary.

(2) Ultrasonic gastroscope: It is helpful to evaluate the depth of gastric cancer invasion and judge the lymph node metastasis around the stomach, and it is recommended for preoperative staging of gastric cancer. This examination is necessary for those who intend to undergo minimally invasive surgery such as endoscopic mucosal resection (EMR) and endoscopic submucosal resection (ESD).

(3) Laparoscopy: For those who are suspected of peritoneal metastasis or intra-abdominal spread, laparoscopy can be considered.

2. Histopathological diagnosis

Histopathological diagnosis is the basis of diagnosis and treatment of gastric cancer. Patients with invasive cancer diagnosed by biopsy receive standardized treatment. If the depth of infiltration cannot be determined by biopsy pathology due to the limitation of biopsy materials, it is suggested that patients with precancerous lesions or suspected infiltration should be repeatedly biopsied or combined with the results of imaging examination to choose a treatment plan after further diagnosis.

(1) Gastroscope biopsy specimen processing.

(1) Specimen pretreatment: After the biopsy specimen leaves the body, flatten the specimen immediately, so that the mucosa basal layer is stuck on the filter paper.

② Specimen fixation: put in 10%- 13% formalin buffer. The fixing time before embedding must be more than 6 hours and less than 48 hours.

③ Paraffin embedding: Take off the filter paper and embed the tissue vertically.

④HE production standard: to trim the wax block, it is required to cut 6 ~ 8 tissue surfaces continuously and fish on the same slide. Routine HE staining and sealing.

(2) Pathological diagnostic criteria.

① Low-grade intraepithelial tumor: The structure and cytological morphology of intramucosal glands are slightly atypical. Compared with the surrounding normal glands, the glands are densely arranged, the glandular tube cells are pseudo-stratified, there is no or less mucus, the nucleus is stained again, and mitotic phase appears.

② High-grade intraepithelial tumor: The glandular structure and cytological morphology in mucosa are seriously atypical (adenocarcinoma in situ). Compared with the surrounding normal glands, the glandular duct is dense, and the arrangement and polarity of glandular duct cells are obviously disordered. On the basis of low-grade intraepithelial tumors, there are * * * walls and even cribriform structures, lack of mucus secretion, active mitosis, focal necrosis but no interstitial infiltration.

③ Mucosal carcinoma: that is, submucosal invasive carcinoma, where irregular nests of glandular epithelial cells or isolated glandular epithelial cells infiltrate into the stroma of lamina propria of mucosa and are confined to the muscularis mucosa.

④ Submucosal carcinoma: that is, the infiltrating carcinoma in the mucosa continues to infiltrate deeply, permeating into the muscularis mucosa, reaching the submucosa, but not the muscularis propria of the stomach.

⑤ Early gastric cancer (T 1N0/ 1M0): including submucosal invasive cancer and submucosal invasive cancer, whether there is evidence of regional lymph node metastasis.

(3) Pathological evaluation.

① Standard of tissue specimen fixation.

Stationary solution: It is recommended to use 10%- 13% neutral formalin stationary solution, and avoid using stationary solution containing heavy metals.

Volume of stationary liquid: it must be greater than 10 times the volume of stationary specimen.

Fixed temperature: normal room temperature.

Fixation time: endoscopic biopsy specimen or mucosal resection specimen: more than 6 hours, less than 48 hours. Specimens of gastrectomy: cut along the greater curvature of the stomach, flattened and fixed, and the fixed time was more than 12 hours and less than 48 hours.

② Material requirements.

A. Biopsy specimens.

Check the number of clinical specimens, and all biopsy specimens must be taken. Each wax block contains no more than 5 biopsy specimens. Wrap the specimen with gauze or soft permeable paper to avoid losing it.

B. endoscopic mucosal resection specimens.

The specimens are flattened and fixed by the surgeon, and the orientation is marked. The size of the tumor and the distance from each position to the margin were recorded. Vertical to the stomach wall, cut the specimen parallel every 0.3cm and divide it into tissue blocks of appropriate size. It is recommended that all materials be taken out in the same embedding direction. Record the direction corresponding to the tissue block.

C. Gastrectomy specimens

A. Tumors and margins: Take tumor tissues fully, and take materials according to tumor size, infiltration depth, different textures, colors and other areas. There are more than 4 tumors, of which the depth of tumor infiltration is full thickness 1-2, so as to judge the deepest level of tumor infiltration. 1-2 pieces of tissue were found at the junction of tumor and adjacent tumor, and the relationship between tumor and adjacent normal mucosa was observed. Cut at least 1 piece of distal and proximal surgical margins. The principle of selecting materials for early cancer: All surgical specimens should be cut into sections, and the location of tissue blocks should be marked with diagrams for reference during follow-up or consultation.

B. Lymph nodes: It is suggested that surgeons send lymph nodes for examination according to local anatomy and intraoperative findings, which is beneficial to the location of lymph node drainage area; Without receiving the doctor's advice or marks from the surgeon, the pathologist should detect the lymph nodes in the sample according to the following principles: all lymph nodes should be taken, and it is suggested that the total number of lymph nodes in patients who have not received treatment before operation should be ≥ 15. All lymph nodes negative to the naked eye should be submitted for inspection, and lymph nodes positive to the naked eye can be partially cut for inspection.

C recommended tissue volume: no more than 2×1.5× 0.3cm.

D. the principle of specimen handling and retention time after sampling.

A. Preservation of remaining specimens: the remaining tissues are preserved in standard fixative, and the concentration of fixative and formaldehyde is always sufficient to prevent the specimens from drying up or tissue rotting due to insufficient fixative or decreased concentration, so as to supplement the specimens at any time according to the needs of microscopic observation and diagnosis, or to review or supplement the general specimens when receiving clinical feedback after the pathological diagnosis report is issued.

B. Time limit for handling the remaining specimens: It is suggested that the hospital handle the case by itself 1 month after the pathological diagnosis report is issued, and no clinical feedback information has been received. Other hospitals have different consultation opinions, so re-examination is unnecessary.

(4) Pathological types.

① General types of early gastric cancer.

Ⅰ: Uplift type

Ⅱ a: surface uplift type

Ⅱ b: flat type

Ⅱ c: surface depression type

Ⅲ: concave type

② General types of advanced gastric cancer.

Uplift type: the tumor body protrudes into the intestinal cavity.

Ulcer type: the tumor reaches deep or penetrates the muscle layer with ulcer.

Infiltration type: the tumor infiltrates all layers of the intestinal wall, thickening the local intestinal wall, but there are often no obvious ulcers or bulges on the surface.

③ Histological types.

A who classification: the most commonly used histological classification method for gastric cancer at present (annex 2).

B. Lauren classification: intestinal type, diffuse type and mixed type.

(5) The contents of pathological report.

A. The pathological report of biopsy specimens must include the following contents:

A. Basic patient information and examination information;

B. Intraepithelial tumor (dysplasia), report classification;

C. Suspicious infiltration: Biopsy should be repeated and immunohistochemical staining should be carried out if necessary;

D. Early invasive carcinoma: showing the depth of infiltration.

Clinicians should understand that due to the limitation of biopsy depth, it may be difficult to confirm the actual infiltration depth through pathological examination of biopsy tissue.

B the pathological report of mucosal resection specimen under endoscope must include the following contents:

A. Basic patient information and examination information;

B. tumor size;

C. classification of intraepithelial tumors (dysplasia);

For invasive cancer, histological classification, grading, infiltration depth, margin and vascular infiltration should be reported.

PT 1 poorly differentiated carcinoma, with vascular invasion and positive margin, should be operated again to expand the resection range. In other cases, endoscopic resection is enough, but regular follow-up is needed after operation.

Histological features of poor prognosis include poor differentiation, vascular and lymphatic infiltration, and positive margin.

The positive margin is defined as: the tumor is less than 65438±0mm from the margin or cancer cells can be seen at the margin of electrosurgical excision procedure.

C the pathological report of surgical specimens must include the following contents:

A. The patient's body shape, gross type, visible infiltration depth, and the distance between the upper and lower margins and the tumor;

C. Degree of tumor differentiation (tumor classification and grading);

D. The depth of tumor infiltration (T stage, T stage or pT) is determined according to tumor cells with morphological basis. After neoadjuvant therapy, there is no acellular mucus lake in the specimen, which is not considered as tumor residue) (see Annex 3 for TNM staging standard);

E. Number of detected lymph nodes and number of positive lymph nodes (N phase);

F. condition of proximal cutting edge and distal cutting edge. If the tumor is close to the margin, the distance between the tumor and the margin should be measured and reported under the microscope. If the tumor is within 65438±0mm from the margin, the margin is positive.

G. vascular and nerve invasion;

H. Special examinations that are helpful to differential diagnosis and guide clinical treatment, including immunohistochemical and molecular pathological examinations, such as HER-2 test.

Clinicians must fill in the pathological diagnosis application form in detail, truthfully describe the surgical findings and related clinical auxiliary examination results, and clearly mark lymph nodes.

3. Laboratory inspection

(1) Blood examination: blood routine, blood biochemistry, serum tumor markers, etc.

(2) Urine routine, stool routine and stool occult blood test.

4. Image inspection

(1)CT:CT plain scan and enhanced scan are of great value in evaluating the pathological range, local lymph node metastasis and distant metastasis of gastric cancer, and should be used as a routine method for preoperative staging of gastric cancer. In the absence of contraindications to the use of contrast media, it is suggested that enhanced CT scanning should be performed when the gastric cavity is in good filling state. The scanning site should include the primary site and the possible metastatic site.

(2) Magnetic resonance imaging (MRI) examination: MRI examination is one of the important imaging examination methods. It is recommended to be used for those who are allergic to CT contrast agents or those who are suspected of metastasis by other imaging examinations. MRI is helpful to judge the status of peritoneal metastasis and can be used as appropriate.

(3) Upper gastrointestinal radiography: It is helpful to judge the scope and functional status of primary gastric lesions, especially air-barium double radiography is one of the commonly used imaging methods for diagnosing gastric cancer. For patients with suspected pyloric obstruction, it is recommended to use water-soluble contrast media.

(4) Chest X-ray examination: It should include positive and lateral phases, which can be used to evaluate whether there are obvious lung lesions such as lung metastases, and lateral phase is helpful to find retropericardial lesions.

(5) Ultrasound examination: It has certain value in evaluating local lymph node metastasis and superficial metastasis of gastric cancer, and can be used as a preliminary examination method for preoperative staging. Abdominal ultrasound examination can know whether the patient has abdominal and pelvic metastases, especially contrast-enhanced ultrasound is helpful to distinguish the nature of the lesions.

(6)PET-CT: routine use is not recommended. For metastatic lesions that cannot be clearly identified by routine imaging examination, it can be used as appropriate.

(7) Bone scanning: routine use is not recommended. For patients with gastric cancer suspected of bone metastasis, bone scanning can be considered.