I. Overview
Esophageal cancer is a disease in which malignant cells (cancer cells) form in the tissues of the esophagus. The esophagus is a hollow muscular tube that can deliver food and liquid from the pharynx to the stomach by peristalsis. The esophageal wall is divided into mucosal layer, submucosal layer, muscular layer and epithelial layer from inside to outside, and esophageal cancer starts in the inner layer of esophageal wall, and then gradually spreads outward to other layers with the growth of cancer cells.
1.The two most common types of esophageal cancer are named according to the type of cells that undergo malignant transformation (carcinoma). They include
Squamous cell carcinoma: also called epidermoid carcinoma. Flat cancer cells are arranged in squamous form in the esophageal wall. This cancer can occur anywhere in the esophagus, but is most common in the upper and middle esophagus.
Adenocarcinoma: The cancer cells originate from glandular cells (secretory cells). These glandular cells can produce and release glandular fluid such as mucus. Adenocarcinoma often occurs in the lower part of the esophagus near the stomach.
2.Risk factors for esophageal cancer include
Smoking
Alcohol abuse
Barrett’s esophagus: Under certain conditions, the cells in the lower esophagus change or are replaced by heterotypic cells that can develop into cancer. Gastric reflux (backflow of stomach contents into the lower esophagus) can irritate the esophagus and, over time, form Barrett’s esophagus.
Advanced age
Male
Ethnicity: e.g. Chinese (Han and some ethnic minorities), Japanese, Mongoloid, Iranian and Black American
The most common symptoms of esophageal cancer are painful or difficult swallowing and weight loss. These common symptoms or other symptoms can be caused by esophageal cancer, but can also be seen in other diseases. You should consult your doctor if you have any of the following discomforts.
Painful or difficult swallowing
Weight loss
Pain behind the sternum
Hoarseness and cough
Indigestion and heartburn
Various tests of the esophagus can be used to detect and diagnose esophageal cancer. Commonly used tests for esophageal cancer are as follows.
Chest X-ray: i.e. X-ray of chest organs and bones. x-ray is a beam of light with energy that can penetrate the body to image various parts of the body on a film.
Barium meal imaging: Also called upper gastrointestinal imaging. It is a series of x-rays of the esophagus and stomach. The patient drinks a silvery-white liquid called barium, which is stained to the esophageal wall, and an x-ray is taken to clarify the presence or absence of esophageal lesions.
Esophagoscopy (often referred to as gastroscopy): can be used to find lesions inside the esophagus. It is a thin, light tube that can be inserted through the mouth or nose and down through the throat into the esophagus. A tissue biopsy can be taken.
Biopsy: Removal of esophageal cells or tissue for microscopic observation to identify the presence of cancer cells. Biopsies are usually taken under the esophagoscope. Sometimes biopsies can reveal precancerous lesions.
Factors affecting prognosis and treatment choice.
Esophageal cancer stage (whether the esophageal cancer involves part of the esophagus or the whole esophagus, whether it has spread to other parts of the body)
Size of the tumor
General health condition of the patient.
When esophageal cancer is detected early and treated timely, the prognosis is better. However, usually esophageal cancer is already in the progressive stage when it is diagnosed. Advanced esophageal cancer can be treated, but rarely cured. These patients may be considered for a clinical trial on improved treatment. Information about clinical trials can be obtained from the NCI website.
II. Staging of esophageal cancer
After esophageal cancer is diagnosed, it is important to check whether the cancer cells have spread in the esophagus or metastasized to other parts of the body, a process called esophageal cancer staging. The information obtained from the staging process determines the stage of the disease. In order to develop a specific treatment plan, it is especially important to clarify the stage. The following tests can be used to stage esophageal cancer.
1.Bronchoscopy: It is a thin light tube inserted from the mouth or nasal cavity down to the trachea and lung, which is used to discover the trachea and large airway lesions in the lung, and biopsy can be taken directly under the microscope.
2, chest X-ray: X-ray of the chest organs and bones. x-ray is a kind of energy beam that can penetrate the body so that various parts of the body are imaged on the film.
3.Laryngoscope: It is a mirror or a light soft tube mirror used by doctors to examine the throat.
4, CT scan: also known as computerized tomography, is the use of x-ray beam on the human body to examine a certain thickness of the level of continuous scanning and take a clear image, these images are connected to the computer processing of the X-ray machine. An imaging agent can be injected into a vein or swallowed to make the tissue and organs appear clearer.
5.Endoscopic ultrasound: Also called endoscopic ultrasound imaging. A tiny ultrasound probe is placed on a thin and light endoscope and inserted into the body, emitting high-energy sound waves that will reflect or scatter to form an echo when they encounter different tissues or organs at the interface during propagation. The image of the human tissue formed by the echo is called an ultrasound map.
6.Thoracoscopy: The chest wall tissue between the two ribs is cut open and a thoracoscope (a light tube) is inserted through the incision to examine the organs in the chest and clarify whether there are lesions. Tissue specimens and lymph nodes may be taken for biopsy. In some cases, it can be used to remove part of the diseased esophagus and lung.
7. Laparoscopy: Several small incisions are made in the chest wall and the laparoscope (a thin light tube) is inserted through one of the small incisions to examine the abdominal organs and clarify the presence of lesions. Other instruments can be used to remove organs or take specimens for biopsy through other incisions or the same incision.
PET scan (positron emission tomography): small doses of radionuclide sugar are injected into a vein, and the PET scanner rotates around the body to scan the parts of the body where sugar metabolism is visualized. Malignant tumor cells are brighter than normal cells due to more active metabolism and more sugar uptake. Therefore, it can be used to detect malignant tumors. As for its role in esophageal cancer staging, clinical trials are underway.
Esophageal cancer staging.
Stage 0: also called carcinoma in situ. Only heterotypic cells are found in the innermost layer of esophagus (mucosal layer), and these heterotypic cells can develop into cancer cells and infiltrate the adjacent normal tissues.
Stage I: Cancer lesions are formed and go beyond the mucosal layer and infiltrate into the esophageal mucosa or submucosa layer.
Stage II: According to the different infiltration sites of esophageal cancer, this stage can be divided into stage IIA and stage IIB.
Stage IIA: Tumor infiltrates the muscular layer or outer membrane.
Stage IIB: esophageal cancer infiltrates any of the first three layers (mucosal layer, submucosal layer and muscular layer), and regional lymph nodes also have metastasis.
Stage III: Esophageal cancer infiltrates the outer membrane of esophagus and regional lymph nodes also have metastasis; or invades the adjacent structures of esophagus.
Stage IV: esophageal cancer has distant metastasis, including lymph node or surrounding organ metastasis.
Recurrent esophageal cancer
Recurrent esophageal cancer refers to esophageal cancer that appears again after the completion of treatment and after a period of remission, which may recur in the esophagus or other parts of the body.
Treatment of esophageal cancer
There are various treatments for esophageal cancer, some of which are standard (the methods usually used nowadays) and some of which are only used in clinical trials. Before treatment begins, patients may consider participating in a clinical trial. A therapeutic clinical trial is a trial designed to improve an existing treatment or to obtain information about a new treatment for a patient with cancer. When a clinical trial confirms that a new therapy is better than the standard therapy, the new therapy can become the standard therapy. Clinical trials are being conducted in many parts of the country, and information on continuing clinical trials can be obtained from the NCI website. The choice of the best treatment is the result of a joint decision by the patient, the family, and the treatment panel.
IV. Common standard therapies
1.Surgery
Surgery is the most common method of treating esophageal cancer. Esophagectomy is a treatment method in which part of the esophagus is removed during surgery, and then the stomach is lifted up to connect with the rest of the esophagus. The surgeon connects the healthy part of the esophagus to the stomach so that the patient can still swallow food. A partial intestinal tube or plastic tube is used as a connector between the two. The lymph nodes surrounding the esophagus also need to be removed and looked at under a microscope to see if they are infiltrated by cancer. If the esophagus is partially obstructed by the tumor, a dilated metal stent (tube) can be placed into the lumen of the esophagus to keep the esophagus open so that food or fluid can pass through the esophagus to the stomach.
2.Radiotherapy
Radiotherapy is the use of high-energy X-rays or other radiation to kill tumor cells. It can be divided into two ways; external and internal irradiation. External irradiation is a method of irradiating tumor foci from outside the body with radiation emitted from radiotherapy machines; internal irradiation is a method of irradiating tumors by enclosing radioactive substances in needles, seeds, threads, or catheters and placing them directly into or next to the tumor. The method of radiotherapy is chosen according to the type of cancer and the stage of the tumor at the time of treatment.
During radiotherapy, a plastic tube can be inserted into the lumen of the esophagus to open the lumen, which is called intraluminal cannula dilation.
3.Chemotherapy
Chemotherapy is a treatment method that uses drugs to inhibit tumor growth by killing tumor cells or inhibiting tumor cell division. When chemotherapy drugs are administered orally, intravenously, or intramuscularly, they can enter the blood stream to reach tumor cells throughout the body (systemic chemotherapy); when chemotherapy drugs are injected directly into the spinal cavity, organs, or body cavity such as the abdominal cavity, the drugs mainly act on cancer cells in these areas (local chemotherapy). The choice of chemotherapy method depends on the type and stage of the tumor at the time of treatment.
4.Laser therapy
Laser therapy is a method of killing tumor cells by using a laser beam (a narrow beam of intense light).
5.Electrocoagulation
Electrocoagulation is a method of killing tumor cells by using electric current.
Other treatment methods are still in clinical trials. Useful information on continuing clinical trials can be obtained from the NCI website or other foreign websites.
Patients with esophageal cancer require special nutritional support during treatment. Many patients with esophageal cancer have poor diets because they have difficulty swallowing after the esophageal lumen is narrowed. Esophageal strictures can be caused by tumor obstruction or by adverse effects of treatment. Some patients need direct intravenous nutrition, others may need a nutrition tube (a lightweight plastic tube inserted through the mouth or nose into the stomach) until they can eat on their own.
Treatment selection is based on stage
Stage 0 is often treated surgically
Treatment for stage I esophageal cancer includes the following.
Surgical treatment
Chemotherapy plus radiation therapy clinical trials with or without surgery
Pre- or post-operative clinical trials of new therapies
Stage II esophageal cancer treatment includes the following
Surgery
Chemotherapy plus radiotherapy clinical trials with or without surgery
Pre- or post-operative clinical trials of new therapies
Treatment of stage III esophageal cancer includes
Surgery
Chemotherapy plus radiotherapy clinical trials with or without surgery
Pre- or post-operative clinical trials of new therapies
Treatment of stage IV esophageal cancer includes
External radiation radiotherapy or internal radiation radiotherapy as a palliative treatment to relieve symptoms and improve patient’s quality of life
Laser surgery or electrocoagulation as a palliative treatment to relieve symptoms and improve the patient’s quality of life
Chemotherapy
Clinical trials of chemotherapy
Treatment of recurrent esophageal cancer includes
Application of any standard therapy as a palliative treatment to relieve symptoms and improve patient quality of life
Clinical trials of new preoperative or postoperative therapies