The esophagus is a muscular tube measuring 20-25 cm (8-10 in) long and 2-3 cm (0.75-1.25 in) wide that serves as a conduit for moving food and drink from the mouth to the stomach. Two major types of esophageal cancers exist, as follows:
Squamous cell carcinoma arises from the epithelial cells that line the esophagus.
Adenocarcinoma arises from the esophageal glands or within a segment of Barrett’s esophagus.
Cancer cells can spread by breaking away from the original tumor. They may enter blood vessels or lymph vessels, which branch into all the tissues of the body. The cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues. The spread of cancer cells is called metastasis. See the Staging section for information about esophageal cancer that has spread.
The wall of the esophagus has several layers:
Inner layer or lining (mucosa): The lining of the esophagus is moist so that food can pass to the stomach.
Submucosa: The glands in this layer make mucus. Mucus keeps the esophagus moist.
Muscle layer: The muscles push the food down to the stomach.
Outer layer: The outer layer covers the esophagus.
Symptoms of Esophagus Cancer
Usually, the patient does not experience any symptoms during the early stages of esophagus cancer. When the cancer advances some of the symptoms that the individual can experience are:
Difficulty in swallowing: The medical term for this condition is dysphagia. This is the most common symptom of esophagus cancer and the patient does not experience the discomfort till the cancer has narrowed down the esophagus to half its normal size. Diet will have to be changed drastically and eventually it will become difficult to swallow liquids too.
Weight loss: As eating becomes more difficult, the individual will not be able to maintain a regular diet which will cause weight loss. Further, cancer by itself causes muscle wasting and weight loss as it changes the way the body metabolizes nutrients.
Pain: Esophagus cancer is often accompanied by pain in the throat, mid-chest or in between the shoulder blades. There can also be discomfort or burning sensation behind the breastbone when the individual swallows.
The individual may also suffer from hoarseness, hiccups and vomiting of blood but these symptoms only appear when the cancer is in the advanced stage.
Stages In Esophagus Cancer
(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.