1. The task of preventing and treating gastric cancer in China is arduous
Stomach cancer is one of the most common malignant tumors in the world, and there are regional differences in its incidence[2]. my country is an area with a high incidence of gastric cancer. According to the data from the National Cancer Registry, ,In 2015, the incidence of gastric cancer in China was second only to lung cancer, ranking second among all malignant tumors, with a total of 679,000 new cases and 498,000 deaths[2].
[ Only about 10%), advanced cases are the main targets of diagnosis and treatment, etc.[4]. Especially in recent years, patients with newly diagnosed gastric cancer have shown a younger trend. In the 30 years from the 1970s to the 2010s, the proportion of young patients under the age of 30 has jumped from 1.7% to 3.3%[4].
Therefore, The burden of gastric cancer in my country is heavy, and the task of prevention and treatment is arduous. How to prevent gastric cancer has become the best strategy to crack the burden of gastric cancer.
Second, Cause prevention is an important measure for gastric cancer prevention< /span>
In the 1980s, preventive medicine experts put forward the concept of three-level prevention of chronic diseases including cancer: one Primary prevention is pathogenic prevention; secondary prevention refers to early detection, early diagnosis, and early treatment; tertiary prevention refers to clinical prevention or rehabilitation prevention. Among them, primary prevention, that is, prevention of the cause of the disease, is the top priority in cancer prevention and control.
pyloric Helicobacter (Hp) infection is the main cause of gastric cancer About 75% of gastric cancer is caused by Hp infection [5], about 90% of the occurrence of non-cardia gastric cancer is closely related to Hp infection[6]. As early as 1994, the International Agency for Research on Cancer (IARC) under the WHO has listed Hp as a Class I carcinogen of human gastric cancer[7]. Prospective epidemiological investigations showed that the risk of gastric cancer in patients with Hp infection increased by 2.3 to 6.2 times[8].
At present, there is no effective vaccine that can prevent Hp infection, only drug treatment can eradicate Hp. Hp Eradication treatment is the primary prevention strategy for gastric cancer.
In recent years, studies have proved the actual benefit of eradicating Hp in reducing the incidence of gastric cancer. A 14.7-year follow-up study conducted in Linqu, Shandong, a high-incidence area of gastric cancer in my country, showed that eradication of Hp reduced the incidence of gastric cancer[9]. In the Matsu area of Taiwan, China, a large-scale eradication of Hp infection has been carried out for people over 30 years old since 2004. The data after 4 years of follow-up also found that the rate of gastric mucosal atrophy and the incidence of gastric cancer have decreased significantly[ 10]. A study from South Korea published in the New England Journal in 2020 proved that after Hp eradication by first-degree relatives of gastric cancer patients, the risk of gastric cancer is reduced by 73%, and the annual incidence of gastric cancer is only 0.8%[11] .
3. How to prevent the cause of gastric cancer?
1.Determine the time and crowd to eradicate Hp
"Normal gastric mucosa-non-atrophic gastritis-atrophic gastritis-intestinal metaplasia-dysplasia-gastric cancer" is a recognized pattern of intestinal gastric cancer. Hp infection is one of the factors of gastric mucosal lesions ranging from superficial gastritis to severe atrophic gastritis[12]. The results of the study show that before the development of severe atrophic gastritis and intestinal metaplasia, that is, the early stage of Hp infection is the best preventive effect span>[13]. The vast majority of Hp infections occur in childhood [14], approximately between 6 and 15 years of age[15,16]. The World Health Organization issued IARC's "One of the Strategies for Gastric Cancer Prevention: Eradication of Helicobacter Pylori" in 2004, which proposed that eradicative treatment of Hp infection in children and young people may be the best choice for gastric cancer prevention[13 ]. In addition, studies in Japan have shown that for the purpose of preventing gastric cancer, the best age for eradication of Hp infection is 12-20 years old. However, in my country, the age at which gastric mucosal atrophy and intestinal metaplasia occur after Hp infection is unclear[ 17].
At present, chronic gastritis with dyspepsia, gastric mucosal atrophy or erosion are the recommended indications for Hp eradication, global Kyoto consensus It is also proposed that all patients with Hp infection should be given eradication treatment, unless there are countermeasures for consideration[18]. In clinical practice, for those with a family history of gastric cancer or symptoms of stomach discomfort, medical workers should mobilize them to perform Hp testing. Those who are detected as positive for Hp should be mobilized for standardized Hp eradication treatment[19].
In addition, Chen et al. [20]’s meta-analysis results suggest that in patients with gastric cancer Patients undergoing Hp eradication therapy can reduce the occurrence of metachronous gastric cancer.
my country has a vast territory, large population, unbalanced economic development, large regional differences in the incidence of Hp infection and gastric cancer. Screening and treatment are not suitable for the current situation. "The Fifth National Consensus Report on the Treatment of Helicobacter Pylori Infection" [21] has recommended "Hp screening and treatment for high-risk areas and high-risk groups of gastric cancer", which should be more cost-effective Screening strategies for asymptomatic patients.
2.Choose the appropriate screening and detection methods for Hp
StandardDetermining Hp-infected patients is the first step to implement a prevention strategy based on Hp eradication of gastric cancer. There are many detection methods for Hp infection, which can be divided into two categories. One is invasive detection, such as rapid urease method and silver staining method. This type of method requires gastroscopy, which is invasive, is cumbersome and has low patient acceptance, and is not suitable for large sample screening. The other is non-invasive testing, such as urea13C/14C breath test, serum Hp current infection protein antibody detection and serum Hp urease antibody detection, the detection methods have their own advantages and disadvantages, and further research is needed to determine the suitability for large-scale Detection methods for population screening.
Currently, Clinical The most commonly used non-invasive method is the urea breath test. This method has the advantages of relatively high accuracy, convenient operation and not affected by the focal distribution in the stomach.[21 ]. However, in patients after partial gastrectomy, severe diffuse atrophic gastritis, bile reflux gastritis, gastric bleeding, and recent medications that affect breath detection, the accuracy of the breath test will be affected.
3.Take standardized Hp eradication treatment
Success Eradication of Hp is a key part of preventing gastric cancer. Although the difficulty in eradicating Hp is increasing with the increase in resistance rate of Hp, so far, Hp can still be effectively eradicated with drugs[22]. Quadruple therapy is currently recommended, which can be divided into bismuth quadruple therapy (bismuth + proton pump inhibitor + 2 antibiotics) and non-bismuth quadruple therapy (proton pump inhibitor + 3 antibiotics). my country mainly recommends bismuth quadruple therapy therapy. according to the 7 programs recommended by our country’s consensus, a course of 14d Hp eradication The rate can still reach 90%[22].
4. Japan’s experience in gastric cancer prevention is worth learning. The combination of primary and secondary prevention can improve the prevention effect< /span>
As a country with a high incidence of gastric cancer, Japan began screening for gastric cancer more than 30 years ago Check [23], and continue to improve screening methods, but while the early cancer detection rate is increasing, it cannot significantly reduce the incidence of gastric cancer[24]. Later, Japan proposed a new gastric cancer prevention strategy combining primary prevention (Hp-positive patients undergoing eradication therapy) combined with secondary prevention (screening and follow-up of high-risk groups of gastric cancer). This new strategy has achieved a good effect in reducing the incidence of gastric cancer and is worth learning.
The specific implementation steps of this gastric cancer prevention strategy are as follows[25]:
1.Because adolescents can almost completely prevent the occurrence of gastric cancer after Hp eradication, all junior and high school adolescents will be tested for Hp. If the test is positive, eradication treatment will be carried out immediately;
2.Patients with stomach discomfort should undergo endoscopy and Hp examination first;
3.Hp-positive patients should be treated with Hp eradication;
4. Patients with gastric mucosal atrophy shall have regular endoscopic follow-up every 1-2 years;
5. Patients without gastric mucosal atrophy only need individual selective routine follow-up;
6.Hp-negative patients only need individual selective routine follow-up;
7. Patients with gastric cancer should be given active treatment.
Five. Conclusion
The occurrence of gastric cancer is the result of Hp infection, environmental factors and genetic factors. But Hp infection is the most important and controllable risk factor. A gastric cancer prevention strategy combining primary prevention of Hp eradication and screening of high-risk groups of gastric cancer with follow-up secondary prevention has been implemented and verified in Japan. The exploration of gastric cancer prevention strategies suitable for China is essential for reducing the occurrence of gastric cancer and reducing the burden of disease caused by gastric cancer.
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