Esophageal cancer is a common gastrointestinal tumor that kills about 300,000 people worldwide each year. Its incidence and mortality rates vary greatly from country to country. China is one of the regions with high incidence of esophageal cancer in the world, with an average of about 150,000 deaths per year. There are more men than women, and the age of onset is mostly above 40 years old. The typical symptom of esophageal cancer is progressive difficulty in swallowing, firstly, it is difficult to swallow dry food, then semi-liquid food, and finally, water and saliva cannot be swallowed.
Etiology
The population distribution of esophageal cancer is related to age, gender, occupation, race, region, living environment, dietary habits and genetic susceptibility. Investigation data have shown that esophageal cancer may be a disease caused by multiple factors.
The proposed etiologies are as follows.
1. Chemical etiology
Nitrosamines. These compounds and their precursors are widely distributed and can be formed inside and outside the body, and are highly carcinogenic. The nitrite content in the diet, drinking water, sauerkraut, and even saliva of patients in high incidence areas is much higher than that in low incidence areas.
2. Biological etiology
Fungi. In some high incidence areas, a variety of fungi can be isolated from food, upper gastrointestinal tract of esophageal cancer patients or resected specimens of esophageal cancer, some of which have carcinogenic effects. Some fungi can promote the formation of nitrosamines and their precursors, which can further promote the occurrence of cancer.
3. Lack of certain trace elements
Low content of molybdenum, iron, zinc, fluorine and selenium in food, vegetables and drinking water.
4. Lack of vitamins
Lack of vitamin A, vitamin B2, vitamin C and insufficient intake of animal protein, fresh vegetables and fruits is a common feature of high incidence area of esophageal cancer.
5. Smoking, alcohol, hot food, hot drinks, unclean mouth and other factors
Long-term consumption of strong alcohol, addiction to smoking, food that is too hard, too hot, eating too fast, causing chronic irritation, inflammation, trauma or unclean mouth, dental caries, etc. may be related to the occurrence of esophageal cancer.
6. Genetic susceptibility factors of esophageal cancer.
Clinical manifestations
1.Early stage
Symptoms are often not obvious, but there may be different degrees of discomfort when swallowing coarse and hard food, including choking sensation of swallowing food, burning, pinching or pulling and rubbing pain behind the sternum. Food passes slowly and there is a sensation of stagnation or foreign body. The choking sensation is often relieved by swallowing water and disappears. The symptoms are sometimes mild and sometimes severe, and progress slowly.
2.Middle and late stage
The typical symptom of esophageal cancer is progressive difficulty in swallowing, first it is difficult to swallow dry food, then semi-liquid food, and finally water and saliva cannot be swallowed. Often spit mucus-like sputum, which is the secretion of saliva and esophagus from the lower throat. The patient gradually loses weight, becomes dehydrated and weak. Persistent chest pain or back pain indicates advanced symptoms, and the cancer has invaded the extraesophageal tissues. When the inflammatory edema caused by cancer obstruction temporarily subsides or part of the cancer is detached, the obstructive symptoms can be temporarily reduced, which is often mistaken for improvement of the disease. If the cancer invades the recurrent laryngeal nerve, hoarseness may appear; if it compresses the cervical sympathetic ganglion, Horner’s syndrome may arise; if it invades the trachea and bronchus, esophageal, tracheal or bronchial fistula may be formed, and violent choking and coughing when swallowing water or food, and respiratory system infection may occur. Finally, a cachectic state appears. If there are liver, brain and other organ metastases, jaundice, peritoneal effusion, coma and other states may occur.
During physical examination, special attention should be paid to the presence of enlarged lymph nodes on the clavicle, liver masses and signs of distant metastases such as peritoneal effusion and pleural effusion.
Examination
For suspected cases, double contrast X-ray of esophagus with barium swallowing should be done.
Early stage can be seen as.
1.Disorganized, rough or interrupted esophageal mucosal folds;
2. Small filling defects;
3, limited wall stiffness, peristaltic interruption;
4, small niche shadow. In the middle and late stages, there are obvious irregular stenosis and filling defects with stiffness of the canal wall. Ultrasound examination for metastasis to liver and other organs. Laboratory tests include anemia and carcinoembryonic antigen test, and CT for metastases to the brain, lungs, etc.
Differential diagnosis
In early stage without dysphagia, it should be differentiated from esophagitis, esophageal diverticulum and esophageal varices. When dysphagia is present, it should be differentiated from benign esophageal tumor, cardia failure and benign esophageal stricture. The differential diagnosis is based on barium swallow X-ray esophagogram and fiberoptic esophagoscopy.
Treatment
Surgical treatment, radiotherapy, chemotherapy and combination therapy are available. Two or more therapies applied simultaneously or sequentially are called combination therapy. The results show that the combined treatment is more effective.
1. Surgery
Surgery is the first choice of treatment for esophageal cancer. If the patient has good general condition, good cardiopulmonary function reserve and no obvious signs of distant metastasis, surgery can be considered. Generally, cancer of cervical segment <3 cm, upper thoracic segment <4 cm and lower thoracic segment <5 cm has a higher chance to be removed. However, there are also cases where the tumor is not too large but has been closely adhered to major organs, such as aorta and trachea, and cannot be resected. For larger squamous carcinoma, which is estimated to have little chance of resection but the patient's general condition is good, preoperative radiotherapy can be used first, and surgery can be performed after the tumor is reduced. <
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Contraindications to surgery.
(1) Poor systemic condition, cachexia. (1) Poor systemic condition, cachexia, or severe cardiac, pulmonary, hepatic, or renal insufficiency.
(2) Large lesion invasion, obvious signs of invasion and perforation, such as hoarseness or esophagotracheal fistula.
(3) Those who have distant metastases.
2. Radiotherapy
(1) Combined radiotherapy and surgery can increase the surgical resection rate and improve the long-term survival rate. After preoperative radiotherapy, it is more appropriate to rest for 3 to 4 weeks before surgery. Metal markers should be made for residual cancer tissues that are not completely excised during surgery, and postoperative radiotherapy is usually started 3 to 6 weeks after surgery.
(2) Simple radiotherapy is mostly used for cervical and upper thoracic esophageal cancer, which is often difficult to operate, has many complications and unsatisfactory efficacy; it can also be used for those who have contraindications to surgery but the lesion is not long and the patient can still tolerate radiotherapy.
3. Chemotherapy
Combination of chemotherapy with surgery or with radiotherapy and Chinese medicine can sometimes improve the efficacy of treatment, or make patients with esophageal cancer have relief of symptoms and longer survival. However, it is necessary to check the blood picture and liver and kidney function regularly and pay attention to the drug reaction.
Prevention
China started the research on prevention and treatment of esophageal cancer in the late 1950s, and established prevention and treatment research sites in rural areas with high incidence. To the people in the high incidence area, we adopt the education and apply the diagnostic method of esophageal cytology to carry out the screening in order to detect and treat early and improve the cure rate.