Colorectal Cancer is the fourth most common cancer diagnosed in the United States of America each year. In addition to being common, it is dangerous. Colorectal cancer is the second most common cause of cancer deaths for men and the third cause of cancer deaths for women in the United States.
Colorectal cancer develops in the colon; otherwise known as large intestine, and/or the rectum. Through continuous medical research, there are now screening tests that can help detect Colorectal Cancer before it can result in severe disease and/or death. These screening tests help to make Colorectal Cancer either preventable, or treatable at its most early stage.
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In order to better understand Colorectal Cancer, it is essential to understand the normal anatomy of the human body, so that abnormalities can be identified. The gastrointestinal tract begins with the mouth and ends with the anus. The gastrointestinal tract travels from the mouth, down the esophagus into the stomach, which leads to the small intestines. The small intestines then connect to the large intestines. There are four sections to the large intestines or colon. The first portion of the colon is the ascending portion. The first section of the ascending colon is the cecum, which is the area that connects the end of the small intestines to the beginning of the large intestines. The ascending colon, ascends up the abdomen from the right lower quadrant of the abdomen to the right upper quadrant of the abdomen. The next portion of the large intestines is the transverse colon, which runs transverse from the right upper quadrant to the left upper quadrant of the abdomen. The third portion of the abdomen is known as the descending colon, that runs from the left upper quadrant of the abdomen to the left lower quadrant. The fourth and final portion of the large intestines is the sigmoid colon, which is located within the left lower quadrant of the abdomen. This portion of the colon connects with the rectum. The rectum is then connected to the anus and that ends the gastrointestinal tract. The entire colon, or large intestines is approximately 6 feet in length. The purpose of the large intestines is to absorb water and other nutrients; while also removing wastes and expelling those wastes through the stool.
Now that we have a better understanding of the structure and function of the large intestines we can understand how abnormal cancer evolves from normal. Cancer arises when normal cells outlive their destruction. When the normal processes of cell death do not occur, the cells begin to divide independently and in a manner that is out of control. Out of control cell division results in mutations within those cell lines and those mutations can result in abnormalities that transfer to cancer. These particular cell lineages within the colon can actually grow into the rectum, resulting in Colorectal Cancer. The cancer cells may begin to arise in the large intestine and grow into the rectum. From there, the cancer cells can begin to invade lymph nodes and other vascular structures. When these cells reach the vascular system, they can then spread to distant sites in the body. This spreading of cancer is known as metastasis. Metastatic Colorectal Cancer has a poorer prognosis than Primary Colorectal Cancer.
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Colorectal Cancer usually starts out as a small benign polyp within the lining of the large intestines and/or rectum. The growth of these polyps are quite slow and can even take decades to change into cancer. The most common type of polyp is the adenomatous polyp, which is made up of glandular cells that function in producing mucus. It is imperative to understand the signs and symptoms associated with Colorectal Cancer, so that screening and prevention can be at the forefront.