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.
I. Etiology
The population distribution of esophageal cancer is related to age, gender, occupation, race, region, living environment, diet and living habits, genetic susceptibility and so on. According to the investigation data, esophageal cancer may be a disease caused by many factors. The proposed causes 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 the saliva of patients in the high incidence area is much higher than that in the low incidence area.
2.Biological etiology
Fungi. In some high incidence areas, a variety of fungi can be isolated from food, upper digestive 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.Factors such as smoking, alcohol, hot food, hot drinks and unclean mouth
Long-term drinking of strong alcohol, addiction to smoking, food that is too hard, too hot, eating too fast, causing chronic irritation, inflammation, trauma or unclean mouth and dental caries 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.
III. Examination
For suspected cases, double contrast X-ray imaging of the esophagus should be done. In the early stage, we can see: ① disorder, roughness or interruption of esophageal mucosal folds; ② small filling defects; ③ limited wall stiffness and interrupted peristalsis; 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 was performed to check for metastases to the liver and other organs. Laboratory tests include anemia and carcinoembryonic antigen test, and CT examination for metastasis to the brain and lungs.
Differential diagnosis
If there is no dysphagia in the early stage, it should be distinguished from esophagitis, esophageal diverticulum and esophageal varices. In case of dysphagia, it should be distinguished from benign esophageal tumor, cardia failure and benign esophageal stricture. The differential diagnosis is mainly based on barium swallow X-ray esophagogram and fiberoptic esophagoscopy.
V. Treatment
Surgical treatment, radiotherapy, chemotherapy and combination therapy are available. The simultaneous or sequential application of two or more therapies is called combination therapy. The results show that the effect of comprehensive treatment is better.
1.Surgical treatment
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 more 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 or neoadjuvant chemotherapy can be used first, and surgery can be performed after the tumor shrinks. The surgery can be combined with thoracolaparoscopic or open surgery according to the patient’s condition. For lower esophageal cancer, the surgery can be completed by one incision through the left chest. For middle and upper esophageal cancer, the surgery is usually done through three incisions in the upper abdomen and right chest neck or two incisions in the upper abdomen and right chest.
Contraindications for surgery.
①Poor general condition and malignant quality. or those with severe cardiac, pulmonary, hepatic or renal insufficiency.
②Large invasion of the lesion with obvious signs of invasion and perforation, such as hoarseness or esophagotracheal fistula.
(③) Those who have distant metastasis.
2.Radiation therapy
①The combination of radiation 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 are made for residual cancer tissues that are not completely excised during surgery, and postoperative radiotherapy is usually started 3 to 6 weeks after surgery.
②Simple radiotherapy is mostly used for cervical and upper thoracic esophageal cancer, which is often difficult to operate, with 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.
VI. 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 have adopted education and applied diagnostic methods of esophageal cytology to carry out census, so as to achieve early detection and early treatment and improve the cure rate. The incidence of esophageal cancer in Yunnan Province is relatively low and is generally associated with long-term alcohol consumption. Prevention should be implemented mainly in the improvement of drinking habits, such as abstaining from alcohol or drinking less alcohol, especially avoiding alcohol abuse.