1. Esophageal cancer and epidemiology of esophageal cancer
Esophageal cancer is a malignant tumor that occurs in the epithelial tissue of the esophagus and is one of the six most common malignant tumors in the world. About 300,000 people die from esophageal cancer every year worldwide.
China is a high incidence area of esophageal cancer and one of the countries with high mortality rate of esophageal cancer in the world. Esophageal cancer has obvious geographic clustering phenomenon in China, and the areas with high incidence rate and high death rate are quite concentrated. There are several major high incidence areas in China.
1 Taihang Mountains high incidence area includes Linxian County, Henan Province, Shibu County, Hebei Province and Yangcheng County, Shanxi Province.
2 Qinling high incidence area including Danfeng, Shaanxi Province, and Lushan, Henan Province.
3 Dabie Mountain high incidence area including Xinyang Duchuan, Henan, Hubei Xiaogan
4 North Sichuan high incidence area including Yanting, Sichuan
5 Min and Guangdong high incidence area Including Nan’an, Fujian Chaoshan, Guangdong
6 North Jiangsu high incidence area There is Jiangsu Yangzhong Huai’an.
7 Xinjiang high incidence area
China is the highest in Henan Province, and Henan is the highest in Linzhou, which is a world famous esophageal cancer high incidence area and research site.
2. Introduction of esophageal cancer etiology and risk factors.
Systematic research on the etiology of esophageal cancer in China began in the late 1950s, and so far, the exact etiology of esophageal cancer has not been elucidated. The factors that cause esophageal cancer are complex and multifaceted, and are the result of the interaction between multiple environmental factors and host genome, and evolve through a long period of time.
Esophageal cancer etiology introduction and risk factors may be
1 Lifestyle behaviors such as
smoking and alcohol consumption, poor dietary habits such as preferring hot food, fast food, hard food, sauerkraut and pickled food may aggravate esophageal mucosal damage and make it inflammatory and may cause atypical hyperplasia.
2 Nutrition and esophageal cancer
Residents in high incidence areas have a single dietary structure, low intake of fresh vegetables and fruits, and low intake of high quality protein.
Vitamins and trace elements
The lack of trace elements such as iron, molybdenum, zinc, selenium, water-soluble vitamins B and C, and fat-soluble A and E are also related to the occurrence of esophageal cancer.
3 Chemical factors
Highly carcinogenic nitrosamines and polycyclic hydroxyl radicals.
4 Biological factors
Mycobacteria and HPV, recently Helicobacter pylori
5 Genetic factors
Family aggregation and genetic susceptibility
3. What is the relationship between esophageal carcinogenesis and esophageal atypical hyperplasia
How esophageal cancer occurs has been the subject of many researches. The current consensus is that under the long-term stimulation of various factors, chronic inflammation and epithelial hyperplasia of esophageal mucosa occur, and finally cellular carcinoma occurs, resulting in esophageal cancer. However, it does not necessarily mean that the hyperplasia develops into cancer, but the hyperplasia can proceed in two directions: back to normal and cancerous. The incidence of carcinogenesis is about 30%. Those molecular structural changes and genetic mutations that occur in the process of esophageal carcinogenesis causing the esophageal epithelial cells to acquire infinite value-added immortality are the current hot spot and frontier in the prevention and treatment of esophageal cancer.
This theory has been confirmed by pathology. Researchers of thoracic tumor in China have been studying in the high incidence area of esophageal cancer for a long time and found that 1. patients with severe atypical hyperplasia of esophageal mucosa have a significantly higher chance of cancer than those without mucosal hyperplasia. 2. the incidence of esophageal cancer is also higher in areas with higher incidence of esophageal epithelial hyperplasia, and the incidence of both is parallel to each other. 3. observation of resected esophageal specimens reveals that all epithelial cells in the paracancerous tissue of early esophageal cancer have cellular atypical hyperplasia. atypical hyperplasia. The cancer foci were located in the atypical hyperplastic epithelium, and the atypical hyperplasia showed a continuous transition with the carcinoma in situ. All these indicate that the severe atypical hyperplasia of the esophageal epithelium is a precancerous lesion. However, severe atypical hyperplasia will not necessarily develop into esophageal cancer, but severe hyperplastic epithelium can develop toward normal epithelium and restore its normal cell shape, or further develop into esophageal cancer.
The ways of esophageal cancer dissemination.
1. Intra-mural spread The cancer spreads to the submucosa firstly, and then spreads along the esophageal wall with upward and downward infiltration.
2. Direct infiltration: The tumor infiltrates directly into the adjacent organs such as bronchus, aorta and other important organs.
3. Lymph node is not metastasis. Cancer metastasis is mainly through lymphatic route: firstly, it enters into submucosal lymphatic vessels and reaches regional lymph nodes corresponding to the tumor site through muscular layer. Cancer of cervical segment can metastasize to the upper mediastinum, deep cervical and supraclavicular lymph nodes; cancer of thoracic segment can metastasize upward to the mediastinal lymph nodes at the top of the chest, downward to the cardia and perigastric lymph nodes, or under the bulge and lung hilum. Cancer of middle and lower segments can also metastasize to distant supraclavicular and para-aortic lymph nodes.
4. Hematogenous metastasis every time: it occurs later.
Pathological morphological classification of esophageal cancer.
(1) Pathological morphological typing of early esophageal cancer Early esophageal cancer can be divided into occult type, erosion type, plaque type and papillary type, among which plaque type is the most common.
(2) Pathological morphological typing of middle and late stage esophageal cancer can be divided into medullary, myxomatous, ulcerative, narrowing, intraluminal and undetermined types.
Medullary type is the most common and has the highest malignancy. The constricted type presents early obstruction, while bleeding and metastasis occur later. The intraluminal type is less common and has a better prognosis. A few intermediate and advanced esophageal cancers cannot be classified into the above-mentioned types, which are called undetermined types.
Anatomy and clinical segmentation of esophageal cancer
Anatomically, the esophagus is divided into cervical, thoracic and abdominal segments. The total length is about 40 cm, with three stenoses, namely 1 at the entrance of the esophagus, 2 at the intersection with the left bronchus, and 3 through the diaphragmatic esophageal foramen. It is a cancer-prone area.
Clinical division: cervical segment: from the entrance of the esophagus to the entrance of the thorax, about 15-18 cm from the incisors
Upper thoracic segment: from the entrance of the thorax to the level of the tracheal bifurcation, about 18-24 cm from the incisors
Middle thorax: from the tracheal bifurcation to the upper half of the full length of the cardia, about 24-32 cm from the incisors
Lower thoracic segment: tracheal bifurcation to the lower half of the full length of the cardia, about 32-40 cm from the incisors
Clinical manifestations of esophageal cancer
In early stage, the symptoms are often not obvious, and the typical symptoms of middle and late stage esophageal cancer are progressive swallowing difficulty, firstly, it is difficult to swallow dry food, and then semi-liquid and liquid food.
Common symptoms include
1Choking sensation of swallowing food
2. Occult pain under the sternum and glabella: it is obvious when swallowing rough, burning or irritating food
3. Foreign body sensation in the esophagus
4. Dryness and tightness of the pharynx easily misdiagnosed as pharyngitis
5. Posterior sternal stuffiness and swelling is very good discomfort
Late symptoms such as chest and back pain indicate that the tumor has invaded extra-esophageal tissue, hoarseness indicates that the tumor has invaded the recurrent laryngeal nerve, invasion of trachea may form esophagotracheal fistula to choking and coughing when eating. Symptoms such as cachexia, hemorrhage and cancer perforation may appear.
Physical signs such as supraclavicular mass in the neck indicate distant metastasis of tumor.
Diagnosis of esophageal cancer: Gastroscopy and pathology are the main means to confirm the diagnosis of esophageal cancer. Since early esophageal cancer only shows mild changes of mucosa, the diagnosis of early esophageal cancer is more difficult, at present, the diagnosis of early esophageal cancer mostly relies on pigmented endoscopy, which can improve the detection rate of early esophageal cancer after iodine staining.
Upper gastrointestinal tract imaging can clarify the relationship between the onset site and the surrounding tissues and organs, which is of great guidance for clarifying the resection scope and deciding the treatment plan.
Chest CT is helpful to clarify whether there is infiltration of tumor and surrounding tissues and organs, and whether there is distant metastasis.
PET-CT applies radioactive substances to visualize the tumor according to the metabolic characteristics of the tumor, which is beneficial to preoperative staging TNM staging and deciding the surgical approach, but there are also false positive and false negative cases. I have written a review specifically during my postgraduate studies, and I have encountered false-negative cases during surgery. Hunan patients with preoperative limitations resulted in heavier intraoperative adhesions and metastases.
Ultrasound endoscopy is good for understanding the degree of esophageal infiltration and for preoperative T-staging.
Treatment measures of esophageal cancer
It is divided into three major treatment methods: surgery, radiotherapy and chemotherapy
Surgery is the preferred treatment method, which requires removal of most of the esophagus below about 5 cm from the upper cut edge of the tumor, as well as the connective tissue and regional lymph nodes around the tumor, and cervical anastomosis for the upper thoracic and cervical segments, and thoracic apex or arch anastomosis for the middle and lower thoracic segments.
The surgical route includes left open chest, right open chest and cervicothoracic-abdominal triple incision, which are decided according to different lesion sites and lymph node metastasis.
The contraindications for surgery are 1 poor general condition and intolerable cardiopulmonary function, 2 distant and extensive metastasis such as lung, 3 severe local invasion and resection.
Prevention of esophageal cancer
For risk factors of esophageal cancer: anti-mold, ventilation, de-amine, molybdenum fertilization, oral riboflavin, treatment of esophageal epithelial hyperplasia.
For the low cure rate of esophageal cancer, three early detection, early diagnosis and early treatment