Colon Cancer
Colon Cancer
What is the disease?
Colon and rectal cancer develop in the digestive tract, which is also called the gastrointestinal, or GI, tract. The digestive system processes food for energy and rids the body of solid waste matter (fecal matter or stool). Colon cancer and rectal cancer have many features in common. Sometimes they are referred to together as colorectal cancer.
Over 95% of colorectal cancers are ad enocarcinomas. These are cancers of the glandular cells that line the inside of the colon and rectum. Other, less common type of tumors may also develop in the colon and rectum. Carcinoid tumors develop from hormone-producing cells of the intestine. Gastrointestinal stromal tumors develop in the connective tissue and muscle layers in the wall of the colon and rectum. Lymphomas are cancers of immune system cells that typically develop in lymph nodes but may also start in the colon and rectum or other organs.
Colorectal cancers are thought to develop slowly over a period of several years. Before a true cancer develops, there usually are precancerous changes in the lining of the colon or rectum. These changes might be dysplasia or adenomatous polyps. A polyp is a growth of tissue into the center of the colon or rectum. Some types of polyps (hyperplastic polyps and inflammatory polyps) are not precancerous. However, having adenomatous polyps, also known as adenomas, does increase a person's risk of developing cancer, especially if there are many polyps or they are large.
In contrast to the inward growth of a polyp, a true cancer can grow inward toward the hollow part of the colon or rectum, and/or outward through the wall of these organs. If not treated, cells from the tumor may break away and spread through the bloodstream or lymph system to other parts of the body. There, they can form "colony" tumors. This process is called metastasis. The colon has four sections. The first section is called the ascending colon. It
What is the disease?
Colon and rectal cancer develop in the digestive tract, which is also called the gastrointestinal, or GI, tract. The digestive system processes food for energy and rids the body of solid waste matter (fecal matter or stool). Colon cancer and rectal cancer have many features in common. Sometimes they are referred to together as colorectal cancer.
Over 95% of colorectal cancers are ad enocarcinomas. These are cancers of the glandular cells that line the inside of the colon and rectum. Other, less common type of tumors may also develop in the colon and rectum. Carcinoid tumors develop from hormone-producing cells of the intestine. Gastrointestinal stromal tumors develop in the connective tissue and muscle layers in the wall of the colon and rectum. Lymphomas are cancers of immune system cells that typically develop in lymph nodes but may also start in the colon and rectum or other organs.
Colorectal cancers are thought to develop slowly over a period of several years. Before a true cancer develops, there usually are precancerous changes in the lining of the colon or rectum. These changes might be dysplasia or adenomatous polyps. A polyp is a growth of tissue into the center of the colon or rectum. Some types of polyps (hyperplastic polyps and inflammatory polyps) are not precancerous. However, having adenomatous polyps, also known as adenomas, does increase a person's risk of developing cancer, especially if there are many polyps or they are large.
In contrast to the inward growth of a polyp, a true cancer can grow inward toward the hollow part of the colon or rectum, and/or outward through the wall of these organs. If not treated, cells from the tumor may break away and spread through the bloodstream or lymph system to other parts of the body. There, they can form "colony" tumors. This process is called metastasis. The colon has four sections. The first section is called the ascending colon. It
Cited: National Cancer Institute, http://cancernet.nci.nih.gov/wyntk_pubs/colon.htm