Illustration courtesy of the National Cancer Institute

The diagram above illustrates the progression of polyp to a cancer and the cancer's subsequent progression if left untreated. The treatment of colorectal cancer and an individual's prognosis depends greatly on the stage of the tumor once it is discovered. Stage 0 represents the polyp stage where colorectal cancer is virtually 100% cured if the polyp is removed. If left untreated, the polyp can develop into a cancer which will grow and spread throughout the body. For early colorectal cancer in the stage I and early stage II phase, surgery may be all that is needed for successful treatment. However, if the tumor is in the stage III or stage IV phase of development, then more aggressive treatments with chemotherapy and radiation may be necessary.

The majority of colorectal cancer is caused by adenomatous polyps (adenomas) which may grow undetected in the colon. There are generally two factors that determine a polyp's chance of become cancerous: type and size. Even though there are several different types of colorectal polyps, most are generally considered benign. Adenomas however, are most likely to become cancerous if they grow undetected to a large enough size. Generally speaking, the larger a polyp grows, the more likely it is to become cancerous. After a polyp reaches approximately one inch in size, the risk of that polyp being malignant exceeds 20%. Thus it is extremely important to remove polyps no matter how small they are, in order to prevent their growth and progression to colon cancer.
Information courtesy of the National Cancer Institute

What is Cancer?

The body is made up of different types of cells that normally divide and multiply in an orderly way. These new cells replace older cells. This process of cell birth and renewal occurs constantly in the body.
Cancer or malignant growths occur when:
• Some cells in the body begin to multiply in an uncontrolled manner.
• The body's natural defenses, such as certain parts of the immune system, cannot stop uncontrolled cell division.
• These abnormal cells become greater and greater in number.
• In some types of cancer, including colon cancer, the uncontrolled cell growth forms a mass, also called a tumor.
Some tumors are benign, which means that they are not cancerous. Cancerous or malignant tumors grow out of control and can invade, replace, and destroy normal cells near the tumor. In some cases, cancer cells spread to other areas of the body.

Types of growths that occur in the colon:

• Noncancerous growths, such as polyps.
• Malignant or cancerous growths. Colon cancer usually begins with the growth of benign growths such as polyps.
Most types of colorectal cancer are adenocarcinomas. This means that the cancer cells are formed from abnormal gland cells that line the inner surface of an organ. The prefix "adeno" means "gland." In colorectal cancer, the abnormal growth begins to form in the inner lining of the large bowel.

If a polyp develops and is not removed, it may become cancerous. Once a cancer develops it begins to invade the intestinal wall and may spread to nearby lymph nodes. Lymph nodes are part of the lymphatic system, which carries special filtered fluids throughout the body. Through the lymphatic system, cancer cells may also be carried to areas of the body far away the original tumor.
This process of cancer cells traveling to other parts of the body is known as metastasis. The spread of cancer may also occur via the blood stream. Colon and rectal cancers that metastasize through the blood stream will travel first to the liver. There the cancerous cells may continue to grow and develop new tumors. As these new tumors continue to grow and spread further, the function of vital organs, such as the liver, may deteriorate.

About The Digestive System

The digestive system receives food, breaks it down into smaller, useful nutrients, absorbs these nutrients into the bloodstream, and eliminates the remaining waste from the body.
The digestive system is made up of
• The esophagus
• The stomach
• The small intestine
• The large intestine, also known as the colon

The colon has several parts:

• Ascending colon - Beginning in the lower right abdomen and continuing up the right side.
• Transverse colon - Beginning at the upper right side of the abdomen and continuing across to the left side of the abdomen.
• Descending colon - From the left upper abdomen straight down to the left lower side.
• Sigmoid colon - An S-shaped section that leads downward into the pelvic cavity.
• Rectum - The last six or so inches of the colon, ending at the anus.