The type and stage of gastric cancer are clinically important, which directly affect the choice of treatment methods and patients’ prognosis.
There are several classifications of gastric cancer as follows.
1. According to the location of gastric cancer, it can be divided into fundic pancreatic cancer, gastric body cancer, gastric sinus cancer, etc. Different parts of gastric cancer determine different surgical styles. Dai Guanrong, General Surgery Department, Guangzhou General Hospital, Guangzhou Military Region
2.Pathological classification and typing of gastric cancer, which is also the most important
(1) Early gastric cancer: regardless of whether it has lymph node metastasis or not, as long as the cancerous tissue is confined to gastric mucosal layer and submucosal layer, all gastric cancer is called early gastric cancer. Early gastric cancer is divided into augmentation type, superficial type and depression type.
(1) Augmented type: The cancer is more than 5 mm above the gastric mucosa and appears as polyp-like augmentation.
② Superficial type: also called flat type or gastritis type, the cancer has no obvious depression or elevation. If the diameter of the tumor is below 4 cm, it is relatively limited and the boundary is clear, it is called superficial limited type; and if the diameter of the tumor is more than 4 cm, its boundary is mostly unclear, it is called superficial extensive type.
(3) Recessed type: It is called recessed type of gastric cancer if the cancer is confined to the mucosal layer but the ulcer is deep below the submucosal layer. It includes gastric cancer developed from ulcer carcinoma and other types of early gastric cancer.
(2) Progressive gastric cancer: If the tumor tissue has infiltrated into the muscular layer or plasma layer, it is called progressive gastric cancer. Generally, if the tumor tissue has infiltrated into the muscular layer, it is called intermediate gastric cancer, while those beyond the muscular layer are called advanced gastric cancer. According to Borrman’s staging, progressive gastric cancer can be divided into four types: augmented type (polyp type), limited ulcer type, infiltrating ulcer type and diffuse infiltrating type.
(1) Augmented type: the tumor is confined and grows mainly into the lumen in the form of nodules or polyps, with superficial erosion and congestion, ulceration or covered with dirty moss.
②Limited ulcer type: It mainly manifests as a limited ulcer, the bottom of the ulcer is usually not flat, and the edge is elevated in a dike or crater shape. The tumor is confined, disc-shaped, with central necrosis and infiltration to deeper layers, often accompanied by bleeding and perforation.
(3) Infiltrative ulcer type: The cancer grows infiltratively, forming a mass that obviously infiltrates to the surrounding and deeper layers. Due to rapid growth, the central part of the cancer often necroses and forms ulcers. This type of gastric cancer often invades the plasma membrane or has lymph node metastasis earlier.
Diffusely infiltrating type: The cancerous tissues are spread under the gastric mucosa and can invade all layers, and the lesions are light in scope. It makes the stomach cavity smaller and the stomach wall thick and rigid to form leathery stomach.
3.According to the histological characteristics such as the tissue structure, cell shape and differentiation degree of cancer, gastric cancer can be divided into ordinary type and special type.
(1) Ordinary type: including papillary adenocarcinoma, tubular adenocarcinoma, hypofractionated adenocarcinoma, mucinous adenocarcinoma and indolent cell carcinoma.
(2) Special types: adenosquamous carcinoma, squamous carcinoma, carcinoid carcinoma, undifferentiated carcinoma and gastric ulcer carcinoma.
4. Lauren’s staging, which is based on cell morphology and histochemistry, divides gastric cancer into two types: intestinal type and diffuse type.
(1) Intestinal type: mostly occurs in the elderly, with low malignancy and better prognosis.
(2) Diffuse type: with high malignancy and poor prognosis, it mostly occurs in middle-aged and young people.
How many stages of gastric cancer are there?
Stage 0: The tumor infiltrates to the mucosal layer, but does not involve the mucosal lamina propria, and there is no local lymph node metastasis.
Stage IA: Tumor infiltrates to mucosa or submucosa layer without local lymph node metastasis.
Stage IB: tumor infiltrated to mucosa or submucosa layer, accompanied by lymph node metastasis within 3CM from the primary focus; or tumor infiltrated to muscle layer or subplasma layer, but no local lymph node metastasis yet.
Stage II: Tumor infiltrated into mucosa or submucosa layer, but there is local lymph node metastasis beyond 3CM from the primary focus; tumor infiltrated into muscle layer or subplasma layer, but there is only lymph node metastasis within 3CM from the primary focus; or tumor has penetrated into plasma layer, but there is no lymph node metastasis yet.
Stage IIIA: The tumor has infiltrated the muscular layer or subplasma layer, and there is lymph node metastasis beyond 3CM from the primary focus; the tumor has penetrated the outer plasma membrane, but there is only lymph node metastasis within 3CM; or the tumor has invaded the adjacent tissues and organs, but there is no lymph node metastasis yet.
Stage IIIB: The tumor has penetrated into the plasma membrane and has lymph node metastasis beyond 3CM; or the tumor has involved adjacent tissues and organs, but has lymph node metastasis within 3CM.
Stage IV: The tumor has involved adjacent tissues and organs and has lymph node metastasis beyond 3CM from the primary focus; or any T and N with distant metastasis.