The World Health Organization emphasizes that 1/3 of cancers can be prevented and 1/3 of patients can be cured through early diagnosis and appropriate treatment. Prevention of esophageal cancer is undoubtedly the most fundamental measure to control esophageal cancer. According to the multi-stage nature of esophageal cancer development, i.e. initiation, promotion and evolutionary stages, from the viewpoint of etiology, pathogenesis and clinical medicine evolution, prevention of esophageal cancer development can be divided into three levels of prevention.
High-risk groups of esophageal cancer
According to the results of epidemiological, etiological and pathogenetic studies on esophageal cancer, the high-risk groups that are susceptible to esophageal cancer should include the following
High-risk age group: esophageal cancer patients <30 years old are relatively rare, accounting for only 0.5%-1%; >30 years old increases significantly with age; middle-aged and elderly people aged 45-65 years old have the greatest chance of developing esophageal cancer, accounting for 67.3%, which is the high incidence age of esophageal cancer.
Epidemiological studies show that there is an obvious phenomenon of family gathering in the high incidence area of esophageal cancer, that is, the proportion of patients with family history of esophageal cancer increases significantly, and the closer their blood relations are, the higher the relative risk of developing esophageal cancer.
People with long-term exposure to carcinogens There are significant differences in the incidence rates of esophageal cancer in different countries and regions in the world, and the difference between high and low incidence areas can be 100-200 times, showing obvious geographical distribution characteristics, suggesting that some strong carcinogens may exist in high incidence areas. The main carcinogenic factors of esophageal cancer in China are known to be carcinogenic nitrosamines and fungal toxins. These carcinogens are widely exposed to the living environment of residents in the high incidence area and are closely related to people’s poor eating and living habits. People who live in high incidence areas and are exposed to carcinogens for a long time, as well as those who are exposed to carcinogens for a long time in non-high incidence areas have a higher risk of developing cancer and belong to the high-risk group of esophageal cancer and should receive regular preventive checkups.
People with precancerous esophageal lesions and pre-cancerous diseases A large number of animal experiments and population pathology epidemiological studies have proved that esophageal epithelial hyperplasia is a precancerous esophageal lesion. Among them, the cancer rate of severe esophageal epithelial hyperplasia is more than 100 times higher than that of normal esophageal epithelium, which is a high risk factor for esophageal cancer. There are also some benign chronic diseases of esophagus, which can also become cancerous after long time, such as pancreatic atelectasis, esophageal diverticulum, esophageal hiatal hernia, esophageal chemical burns, etc.
Patients with esophageal cancer after surgical treatment Clinicopathological study proves that esophageal cancer often occurs at multiple points and there are extensive epithelial cell proliferation changes around the cancer foci, i.e. pre-cancerous lesions. Different degrees of epithelial cell proliferation lesions can often be seen in the surgically resected paracancerous cells. Patients with recurrence after surgery are often not the recurrence of residual cancer foci, but the carcinogenesis of the original paracancerous epithelial hyperplasia lesions under the action of carcinogenic factors. Therefore, patients after esophageal cancer surgery also belong to the high-risk group and should receive regular checkups.
Primary prevention of esophageal cancer
The vast majority of malignant tumors are the result of long-term interaction between host factors and environmental factors. Eliminating known carcinogenic substances or blocking the contact between these factors and human body will reduce and prevent the occurrence of esophageal cancer, and the experience accumulated from years of practice in high incidence areas proves that these measures are feasible and effective.
It has been found that the content of nitrosamines in water in high incidence areas of esophageal cancer is significantly higher than that in low incidence areas. Therefore, it is very important to improve environmental sanitation and prevent water pollution, gradually reduce the areas of drinking ditch and pond water, and promote drinking tap water. Bleach disinfection should also be applied to the water consumed in ditches and ponds, which can significantly reduce the nitrosamine content in water and kill other infectious bacteria. Control the entry of nitrosamine-contaminated diet and nitrites and nitrates into the body. It has been identified that the increase of nitrate and nitrite content in drinking water and human body in areas with high incidence of esophageal cancer is related to the excessive application of nitrogen fertilizer. Rational use of nitrogen fertilizer, molybdenum fertilizer and zinc fertilizer, according to the ratio of nitrogen, phosphorus and potassium fertilization, not only to save agricultural investment, but also to avoid excessive nitrogen pollution of the environment.
The moldy grain contains a variety of carcinogenic toxins, so it is very important to actively carry out the work of mold and toxin removal, especially the importance of family storage of mold. General grain moisture content <13% can meet the requirements of mold, once found that the grain has mold, should be taken diligent sunshine, picking when eating, multiple washing and alkali treatment, can effectively reduce the intake of mycotoxins. Improve or abolish the food processing method that produces mold and toxins. Promote good food varieties that are resistant to mold.
Do not eat moldy food At present, there is sufficient evidence that the consumption of moldy food, especially sauerkraut, moldy nest and fish sauce is one of the important factors in the development of esophageal cancer, so the danger of such food to human health should be vigorously publicized, so that the masses eat less or do not eat, while encouraging the planting of vegetables and fruits to increase the intake of fresh vegetables and fruits, supplemented with vitamin C. Moldy food, on the one hand, produces mycotoxins or metabolites On the one hand, it promotes the internal synthesis of nitrosamines, which is the main cause of esophageal cancer. Eating more fresh vegetables or supplementing with vitamin C can block the synthesis of nitrosamines in the body, which can reduce the level of nitrosamines exposure in the stomach. In addition, a nutrition prevention trial in Linn County found that riboflavin and niacin supplementation reduced the incidence of esophageal cancer by 15%. Scientific methods of making and preserving sauerkraut should also be actively researched to meet the traditional eating habits that have been developed by local residents for generations.
Improving bad habits Adjusting dietary habits, not eating overheated food, not eating rough and hard food, not being partial to food, diversifying dietary varieties, having a balance of various nutrients, and eating more fresh grains, vegetables and fruits. Eat riboflavin fortified salt. In the diet of high incidence area, riboflavin content is not enough, when lacking, it can promote the growth of esophageal tumor. Do not smoke and drink alcohol in moderation.
Prevention of genetic pathogenic factors Esophageal cancer has a more common phenomenon of family gathering, which indicates that the susceptibility to cancer does exist if there is a family history of esophageal cancer, and the monitoring of the same generation should be strengthened. Families with ≥2 deaths from esophageal cancer in 3 generations should be considered as risk families, and members aged 40-69 in these families should be considered as risk groups for regular medical checkups, provision of preventive drugs or vitamins, and persuasion to change lifestyle habits. This has a positive effect on reducing the incidence of esophageal cancer.
Pathogenetic prevention The epithelial hyperplasia of the esophagus should be treated with Chinese and Western drugs and vitamin B2 to interrupt the cancer process. Diseases related to esophageal carcinogenesis, such as esophagitis, esophageal leukoplakia, esophageal polyps, esophageal diverticulum, cardia incontinentia, etc., are prone to deteriorate and form cancer due to histological changes, functional variation and local stimulation. Close observation, active treatment and effective measures for prevention must be taken.
The pre-cancerous lesions of esophageal cancer mainly refer to heavy hyperplasia of esophageal epithelium. The cancer rate in the treated group was 2.5% in the anti-cancer B III tablet group, 1.4% in the anti-cancer B tablet group and 2.3% in the tylenolone group, which were statistically significant differences compared with the untreated group and more people returned to normal than the untreated group. Anti-cancer tablet is made of 6 Chinese herbal medicines, which is unique in China, with low price and easy to promote.
②Vinamides are the most well established and promising class of tumor preventive drugs. Viamides have strong action, low toxicity and good preventive effect.
③ Riboflavin is an essential vitamin for human body. After taking riboflavin for 5 years, the cancer rate of mild hyperplasia of esophagus decreased by 34.8%, which is 56.8% more than the inhibition rate of mild hyperplasia of 22.2% after taking the drug for 3 years, indicating that the longer riboflavin is taken, the more obvious the effect of inhibiting the cancer of mild hyperplasia. It would be of far-reaching significance if its anti-cancer effect could be further confirmed.
If precancerous lesions are found, this product can prevent further deterioration; garlic and kiwifruit can block the synthesis of nitroso compounds, and dongling grass and rockwool cress can reduce the incidence of nitrosamine-induced esophageal cancer.
Secondary prevention of esophageal cancer
For esophageal cancer, it is impossible to achieve complete primary prevention at present. Since the occurrence and development of esophageal cancer takes a long time, early detection, early diagnosis and timely treatment, especially to stop the development of precancerous lesions, is a realistic and feasible method for tumor prevention.
Popularization of esophageal cancer prevention and treatment knowledge Esophageal cancer is caused by normal epithelial cells of esophageal mucosa stimulated by various factors inside and outside the body and gradually evolves into cancer. It is still unclear how long it takes to develop from normal epithelium to cancer. Generally speaking, it takes several years to develop from heavy hyperplasia of esophageal epithelium to cancer, and about one year to develop from early cancer to middle to late cancer. In the past, it is wrong to think that there are no symptoms and signs of early esophageal cancer. Because these signals and symptoms are mild, appearing and disappearing automatically without treatment, they are ignored by patients and doctors and fail to be further examined and diagnosed, thus losing the best treatment time.
In fact, most patients with early stage esophageal cancer have experienced different types and degrees of self-perceived symptoms, and should be alerted if they find the following symptoms
①Choking sensation when swallowing food.
② Pain behind the sternum and pain in the esophagus when swallowing.
③ Foreign body sensation in the esophagus.
④Slow downward movement of food and a feeling of stagnation.
⑤ Dryness and tightness in the throat.
⑥Sense of stuffiness and swelling behind the sternum.
Screening of esophageal cancer Patients with family history of esophageal cancer or esophageal epithelial hyperplasia in high incidence areas aged >35 years old are considered as high-risk groups and should be monitored with emphasis. Endoscopic examination should be performed as soon as possible to achieve early diagnosis for patients found to be suspicious. The early manifestations of esophageal cancer, such as “discomfort in swallowing”, should be familiar to the general public in the high incidence area, so that the patients can be seen earlier for early diagnosis and treatment.
Screening for esophageal cancer In 2005, the Bureau of Disease Control of the Ministry of Health commissioned the China Cancer Research Foundation to organize relevant experts to prepare the “Guidelines for Cancer Screening and Early Diagnosis and Treatment in China” (for trial implementation). Two protocols are recommended for esophageal cancer screening, and the specific implementation can be chosen according to different situations.
①The best scheme: direct endoscopic screening, applying endoscopy and iodine staining with indicative biopsy, which is highly sensitive and specific and can detect precancerous lesions of different degrees and very early intra-mucosal esophageal cancer, and rarely misses the diagnosis. This is a two-step process of screening and diagnosis in one go. This method is a more technical medical operation, and a group of skilled and experienced medical technicians need to be trained to ensure the accuracy and reliability of screening. This method is more costly and is recommended to be carried out in areas with high incidence of esophageal cancer where the economic situation is better.
②Primary program: A program combining cytological primary screening and endoscopic examination to confirm the diagnosis is adopted. Firstly, cytology screening is performed, and then endoscopy is performed to make histological diagnosis for those with suspicious cytology. Although the sensitivity and specificity of the selected primary screening method are relatively low, this protocol is simple to operate, can greatly reduce the screening cost, can concentrate the high-risk group to a certain extent, and is applicable to the areas with high incidence of esophageal cancer where health resources are lacking.
Tertiary prevention of esophageal cancer
The so-called tertiary prevention is aimed at improving the cure rate, survival rate and survival quality of patients, focusing on rehabilitation, palliative and pain relief treatment.
Patients are provided with standardized diagnosis and treatment plans, and guidance on physiology, psychology, nutrition and rehabilitation. Provide hospice care to improve the quality of survival of patients with advanced disease.