Types of Gastrointestinal Cancers
Anus is an organ that is at the end of the digestive tract rightbelow the rectum. It has two sections:
- The anal canal
- The anus
Anal canal is a 3 to 4 cm long structure between the anal sphincter right below the rectum and the anal verge which has to represent the transition point between both the digestive tract and the skin outside the body.
Muscles inside the anal canal and in the anus have to control the stool from the rectum to the outside of the body. Cancer of Anal is a tumor of either one;
the anal canal or theanal verge. In India, 80% of anal cancers are cell cancers, resembling the cells that are found in the anal canal.
At the same time anal verge cancer is also called as perianal skin cancers. This is because usually they behave more like skin cancers rather than anal cancers.
The longest portion of the large intestine is the colon, it is also known as the large bowel. The last part of the digestive tractis the large intestine.
The largest intestine is a tube, about with about 5 to 6 feet of length; its first 5 feet help in making up the colon, then connecting to about 6 inches long rectum,
and finally ending with the anus. Till the time food reaches the colon which takes about 3 to 8 hours after eating, the nutrients are absorbed and the remaining of the thing is only liquid waste product. The colon has to change this remaining liquid waste into solid stool.
The stool can remain from about 10 hours to several days inside the colon before getting expelled through the anus. The longer stool remains in the colon, the higher is the risk for colon cancer.
Colon cancer is a tissue that grows inside the wall of the colon. Most of the tumors begin when normal tissues inside the colon wall start forming apre-cancerous growth from the colon wall.
As this grows larger, the tumor is formed slowly. This takes many years, therefore allowing time for early detection with screening tests.
- Liver Cancer
The largest solid organ of the body which is located on the right side of the abdomen just beneath the right diaphragm is the liver. The organs surrounding it include the gall bladder which is located just behind the liver, the small intestine, large intestine, the right kidney, and the pancreas. Liver is triangular in shape and it has been divided into two lobes; right and left, the right lobe which is larger of the two. Liver is responsible for providing many important functions to the body like:
- It has to filter the blood in order to remove and has to process toxins
- Synthesizing and excretion of bile, as it is important in processing of fats from our diet
- Regulation of glucose levels
- Production of factors that play an important role in blood clotting
Liver cancer occurs when an error is in the regulation of growth of any of the cells in the liver, including the liver cells as well, the cells of the bile duct, or the blood vessels in the liver.
Tumors in the liver can be either benign or malignant. Benign tumors start to grow uncontrolled. They do not need to break off and to spread beyond where they have started, and they need do not invade into surrounding tissues either. However Malignant tumors, do eventually invade and do damage to other tissues thatare around them. Also they gain the ability of breaking off from where they have started and to be able spread to other parts of the body, this usually happenseither through the blood stream or through the lymphatic system where the lymph nodes have been located. Over the period of time, the malignant tumor cells start to become more and more abnormal and they start to appear less like normal cells. This change of the appearance of cancer cells isknown as the tumor grade.
There are a lot of benign liver tumors. Most common benign tumor of the liver being Hemangiomas, they occur when a benign, tumor that has been filled with blood is formed within the liver. Other benign tumors like adenomas and focal nodular hyperplasia. Although these types of tumors are not responsible for invading surrounding tissues, it is very difficult to describe the difference between benign and malignant tumors while radiographic imaging.