Her Stage IV colon cancer now in remission, Anita Mitchell is working hard to promote awareness and early screenings. Read Anita's Story >

Hear SCCA oncologist Dr. Tony Back talk with interviewer Andrew Shorr about the latest advancements in colorectal cancer treatments explored at the 2007 ASCO convention, on "Patient Power." To listen, click here. 

When it comes to the decline in death rates due to cancer, the most dramatic drop has been in colon cancer deaths. More people are getting screened and there are more drugs to treat it. To read the KING-5 TV special report, click here.

Colorectal Cancer

What does the colon do? 
The colon and rectum are parts of the gastrointestinal (GI) system. As you eat, food drops into the stomach and gastric juices are secreted to break it down. The food and gastric juices are mixed into a thick fluid and then emptied into the small intestine. The small intestine continues to further break down the food and absorbs most of the nutrients. The small intestine joins the colon, which absorbs water and nutrients from the food matter and serves as a storage place for waste before it is eliminated through the rectum and anus. The colon and rectum together form a long, muscular tube called the large intestine. The upper 5 feet to 6 feet of the large intestine is the colon and the lower 5 inches to 6 inches is the rectum.

What is colon cancer? Cancer begins when cells in the colon or rectum become abnormal and divide without the body's normal control or order. This leads to a mass called a tumor. Cancer cells invade and destroy the tissue around them. They can also break away from the tumor and spread to form new tumors in other parts of the body (metastisis).

The cancer can begin in any of the four sections of the colon—the ascending colon, the transverse colon, the descending colon, or the sigmoid colon—or in the rectum. Each of these sections has several layers of tissue. Cancer starts in the innermost layer and can grow through any or all of the layers. Most cancers begin in the sigmoid colon just above the rectum.

In most cases, colon and rectal cancers develop slowly over a period of several years. Most of these cancers begin as a growth of tissue called a polyp into the center of the colon or rectum. Adentomatous polyps become cancerous; more than 95 percent of colon and rectal cancers are adenocarcinomas. Removing the polyp early may prevent it from becoming a cancerous tumor.

Other colon cancer types
Other types of colorectal cancers include carcinoid tumors, gastrointenstinal stromal tumors, and lymphomas.

Gastrointestinal carcinoid tumors happen when cancer cells develop in certain hormone-making cells in the gastrointestinal system. These cancers are rare and are not discussed here.

When colorectal cancers are caught early, they have a high cure rate. Because colon cancer becomes more common as people age, doctors recommend that certain tests—such as a sigmoidoscopy or a colonoscopy—be performed at regular intervals after age 50, and more frequently for people with a family history of the disease.

At Seattle Cancer Care Alliance, our doctors can offer you the latest treatments, including those available only through a clinical trial. Our doctors are dedicated to providing outstanding medical care to all our patients.

December 2007