The incidence rate of stomach cancer is high in China, and the age of prevalence is over 50 years old, and the ratio of male to female incidence rate is 2:1.
Causes
1.Geographical environment and dietary and living factors
There are obvious geographical differences in the incidence of gastric cancer, and the incidence rate of gastric cancer in northwest and eastern coastal areas of China is significantly higher than that in southern areas. The high incidence of distal gastric cancer in people who consume fumigated and salted food for a long time is related to the high content of carcinogens or former carcinogens such as nitrite, fungal toxins and polycyclic aromatic hydrocarbon compounds in food; the risk of gastric cancer in smokers is 50% higher than that in non-smokers.
2.H. pylori infection
The rate of Hp infection in adults in China’s high incidence area of gastric cancer is over 60%. H. pylori can promote the conversion of nitrate into nitrite and nitrosamines and cause cancer; chronic inflammation of gastric mucosa caused by Hp infection plus environmental pathogenic factors accelerate the overproliferation of mucosal epithelial cells, leading to aberration and cancer; the toxic products of H. pylori, CagA and VacA, may have cancer-promoting effects, and the detection rate of anti-CagA antibody in gastric cancer patients is significantly higher than that of the general population.
3.Pre-cancerous lesions
Gastric diseases include gastric polyps, chronic atrophic gastritis and residual stomach after partial gastrectomy. These lesions may be accompanied by chronic inflammatory process of different degrees, intestinal epithelial metaplasia or atypical hyperplasia of gastric mucosa, which may be transformed into cancer. Precancerous lesions refer to pathological histological changes in the gastric mucosa that are prone to cancer, and are junctional pathological changes in the process of transformation from benign epithelial tissue to cancer. The heterogeneous hyperplasia of gastric mucosa epithelium is a precancerous lesion, which can be classified as mild, moderate or severe according to the degree of cell heterogeneity. It is sometimes difficult to distinguish between severe heterogeneous hyperplasia and early gastric cancer with better differentiation.
4.Heredity and genes
Genetic and molecular biology studies show that the incidence of gastric cancer is four times higher in blood relatives of gastric cancer patients than in the control group. The carcinogenesis of gastric cancer is a multifactorial, multi-step and multi-stage development process, involving changes of oncogenes, oncogenes, apoptosis-related genes and metastasis-related genes, etc., and the forms of genetic changes are also various.
Clinical manifestations
Most patients with early stage gastric cancer have no obvious symptoms, while a few have nausea, vomiting or upper gastrointestinal symptoms similar to ulcer disease. Pain and weight loss are the most common clinical symptoms of progressive gastric cancer. Patients often have clear upper gastrointestinal symptoms, such as upper abdominal discomfort, fullness after eating, and as the disease progresses, upper abdominal pain increases, appetite decreases and weakness. Depending on the location of the tumor, there are also its special manifestations. Gastric cancer near the pylorus may show pyloric obstruction; Gastrointestinal bleeding symptoms such as vomiting blood and black stool may occur after the tumor destroys blood vessels. Persistent pain in the abdomen often indicates that the tumor extends beyond the stomach wall, such as enlarged supraclavicular lymph nodes, ascites, jaundice, abdominal mass, and masses in the anterior rectal recess. Patients with advanced gastric cancer may often show anemia, emaciation, malnutrition or even cachexia.
Examination
1.Fiber gastroscopy
It is the most effective method to diagnose gastric cancer, which can directly observe the location and scope of gastric mucosa lesions and obtain lesion tissues for pathological examination. It is the most effective way to diagnose gastric cancer. Using fibergastroscope with ultrasonic probe to detect and image the lesion area, it can help to understand the depth of tumor infiltration and whether there is invasion and metastasis of surrounding organs and lymph nodes.
2.X-ray barium meal examination
The application of digital X-ray gastrointestinal imaging technology is still a common method to diagnose gastric cancer. The diagnosis is often made through the observation of mucosal phase and filling phase by using dual gas-barium imaging. The main change of early gastric cancer is mucosal phase abnormality, and the morphology of progressive gastric cancer is basically the same as the general typing of gastric cancer.
3.Abdominal ultrasound
In the diagnosis of gastric cancer, abdominal ultrasound is mainly used to observe the infiltration of adjacent organs of stomach (especially liver and pancreas) and lymph node metastasis.
4.Spiral CT and positron emission imaging
Multi-row spiral CT scan combined with 3D stereo reconstruction and simulated endoscopy technology is a new non-invasive examination means, which is helpful for the diagnosis and preoperative clinical staging of gastric cancer. Using the affinity of gastric cancer tissue for fluorine and deoxy-D-glucose (FDG), positron emission imaging (PET) can determine lymph nodes and distant metastases with high accuracy.
Treatment
1.Surgical treatment
(1) The principle of radical surgery is to remove part or all of the stomach, including the cancer foci and the potentially infiltrated stomach wall, and to clear the lymph nodes around the stomach and reconstruct the digestive tract according to the D2 surgical standard.
(2) Palliative surgery is performed to relieve the symptoms caused by complications such as obstruction, perforation, bleeding, etc., such as gastrojejunostomy, jejunostomy, perforation repair, palliative gastric resection, etc. The primary foci cannot be removed.
(3) Minimally invasive treatment Currently, laparoscopic radical resection for early-stage gastric cancer and some progressive gastric cancers is increasingly accepted by doctors and patients. It is less invasive, less fluid loss, less bleeding and faster postoperative recovery.
2.Chemotherapy
Preoperative chemotherapy is a new tool in recent years, which can shrink tumors and metastases, and is a way to obtain resection in previously unresectable cases and obtain longer survival. Adjuvant is used for intraoperative and postoperative of radical surgery to prolong the survival. Regular chemotherapy is used for patients with advanced gastric cancer to slow down the development of tumor and improve prognosis. In principle, adjuvant chemotherapy is not necessary after radical surgery for early gastric cancer. Those who have progressive gastric cancer after radical surgery, palliative surgery or recurrence after radical surgery need chemotherapy.
The common routes of chemotherapy administration for gastric cancer include oral administration, intravenous and peritoneal administration, and regional perfusion administration by arterial cannulation. Commonly used oral chemotherapeutic agents include Tegeo, Siroda, etc. Commonly used intravenous chemotherapy drugs include oxaliplatin, paclitaxel, fluorouracil, adriamycin, etc.
3.Other treatments
Including targeted therapy, radiotherapy, immunotherapy, Chinese herbal medicine treatment, etc. Anti-angiogenic targeted drugs are the more researched gene therapy methods, which can play a synergistic role in the treatment of gastric cancer.
Prognosis
The prognosis of gastric cancer is related to the pathological stage, site, tissue type, biological behavior and treatment measures of gastric cancer.