(2) Risk factors
(3) Signs & Symptoms
(5) Diagnosis as per modern science
(1) Overview: -
The esophagus connects the mouth to the stomach and carries food into the stomach. The esophagus is 10 to 13 inches in length. Adult person’s esophagus under normal circumstances is three quarters of an inch at it’s smallest point.
The wall of the esophagus consists of several layers. Cancers of esophagus start from its inner layer and grows outward. The inner layer of the esophagus is called mucosa, which consists of mainly two parts, the epithelium and the lamina propria. The epithelium forms the lining of the esophagus and is made from cells called squamous cells. The lamina propria is a thin layer of connective tissue right under the epithelium.
There is a thin layer of muscle tissue under the mucosa called the muscularis mucosa. The next layer is sub-mucosa. Some parts of the esophagus have mucus-secreting glands in this layer. The layer under the sub-mucosa is a thick band of muscle called muscularis propria. This layer of muscle contracts in a coordinated, rhythmic way to force food along the esophagus from the throat to the stomach. The outermost layer of the esophagus is formed by connective tissues. It is called adventitia.
The upper part of the esophagus has a special area of muscles at its beginning that relaxes to open the esophagus when it senses food or liquid coming towards it. This muscle is called the upper esophageal sphincter. The lower part of the esophagus that connects to the stomach is called the gastroesophageal junction, or GE junction. There is a special area of muscle near the GE junction called the lower esophageal sphincter. The lower esophageal sphincter controls the movement of food from the esophagus into the stomach and it keeps the stomach’s acids and digestive enzymes out of the esophagus.
There are two main types of esophagus cancer. Squamous cell carcinoma, and adenocarcinoma. Since the entire esophagus is normally lined with squamous cells, squamous cell carcinoma can occur anywhere along the length of the esophagus.
Adenocarcinoma starts in glandular tissues, which normally does not cover the esophagus. Before an adenocarcinoma can develop, glandular cells must replace an area of squamous cells as in baret’s esophagus.
(2) Risk factors: -
(a) Age: - The incidence of esophageal cancer, or rate of occurrence, increases with age and peaks around age 70-80 years old. Nearly 80% of people diagnosed are between ages, 55 and 85.
(b) Gender: - Compared with women, men have a 3 fold higher rate of esophagus cancer.
(c) Race: - Some tribes in Africa drink locally prepared beer which contains Nitrosamine, a well known carcinogen, which results in a very high rate of cancer.
(d) Tobacco & Alcohol: - The use of tobacco products along with drinking alcohol increases the chances of developing esophageal cancer.
(e) Obesity: - Being overweight is a definite risk factor for developing esophageal cancer, the risk of this cancer is increased by 50% in overweight people.
(f) Baret’s esophagus: - Is a condition caused due to reflux of stomach acids into the lower esophagus. The symptom that may occur is heartburn. Baret’s esophagus is a high risk factor for developing adenocarcinoma type cancer.
(g) Gastroesophageal reflux disease: - Long term GERD can increase the person’s risk of developing esophageal cancer.
(h) Diets: - Diets lacking in fruits, vegetables, minerals and vitamins, may increase the risk of esophageal cancer. Certain dietary habits specific to geographic location may lead to esophageal cancer.
(i) Occupational Exposure: - Industrial workers exposed to carcinogenic chemicals have a very high risk of developing cancer.
(j) Chemical ingestion: - Accidental chemical ingestion in childhood can lead to esophagus cancer in adulthood.
(k) Achalasia: - In this disease, the lower esophageal sphincter does not relax properly to allow food/liquid to pass into the stomach. The cause of this disease is probably a defect of nerve cells in the lower esophagus that keeps the lower esophagus sphincter from relaxing and thus makes it difficult to swallow. The esophagus above this narrowing becomes dilated and retains food. A small percentage of Achalasia patients do develop esophagus cancer.
(l) Tylosis: - Tylosis causes excess growth of the top layer of skin on the palm of the hands and soles of the feet. People with this condition have a very high risk of developing esophagus cancer.
(3) Signs & Symptoms: -
(a) Dysphagia:- The most common symptom of esophagus cancer is difficulty swallowing, or Dysphagia, with the sensation of food getting stuck in the throat or chest. The opening of the esophagus is narrowed by the tumor causing this symptom.
(b) Pain: - In some cases patients can have mild chest pain or discomfort, a slight pressure sensation, or burning. Painful swallowing is usually a late sign of a large cancer blocking the opening of the esophagus. This pain can occur a few seconds after swallowing food or liquid as it reaches the tumor and cannot pass it.
(c) Weight loss: - About half of patients with esophagus cancer complain of unintended weight loss. This happens because they cannot swallow enough food and nutrition to maintain their weight. Early in the disease, this may go unnoticed. Cancer can also cause a decreased appetite and can affect a person’s metabolism.
Some of the most common symptoms of Esophagus cancer:-
(ii) Significant weight loss without dieting.
(iii) Avoidance of solid food because of pain, when the patient swallows.
(iv) Hiccups and Dysphagia together.
(4) Metastasis: -
Esophagus cancer when detected has spread rapidly inside to distant organs in most of the patients. This cancer spreads directly to trachea, lungs, pleura, throat, stomach and digestive organs. This cancer more predominantly spreads through the lymphatic system faster than though blood.
(5) Diagnosis as per modern science
(i) Barium swallow or upper GI tract X rays.
(ii) Upper endoscopy.
(iii) Computed tomography.
(iv) Endoscopic ultrasound.
(6) Staging: -
(a) Stage 0: - Is called carcinoma in situ, the cancer is still in very early stage and is found only in the first layer of cells lining the esophagus and has not reached the inner membrane, which is the first layer of mucosal lining.
(b) Stage I: - Cancer is found in only a small part of the esophagus and has not spread to adjacent tissues, lymph nodes, or other organs.
(c) Stage II: - Cancer is found in a large segment of the esophagus and has spread to all sides of the esophagus, and may have spread to the local lymph nodes. But it has not spread to adjacent organs.
(d) Stage III: - Cancer has spread to the lymph nodes near the esophagus and also to the tissues and organs near the esophagus but has not shown any signs of distant spread.
(e) Stage IV: - Cancer has spread to distant parts of the body.