Colorectal (Colon) Cancer Slideshow Pictures Digestive Disease Myths Slideshow Pictures Medical Illustrations of Colon Cancer Collection

Medical Author:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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A Surprising Colon Cancer From diagnosis to treatment, a fighting tale. An Unexpected Challenge Wed., Dec. 7, 2005 At the time, I had no idea anything at all was wrong. I just knew it was time for a colonoscopy. In fact it was past time, since I was 61 years old. I don't remember the procedure itself. What I do remember is waking up at home and Kim, my husband, telling me that they'd found a tumor at the very far end of my colon and that the doctor wanted to speak to me when I was awake and ready to talk. I called the doc right away. The doctor told me that he was totally surprised when he found the tumor, that it was being biopsied, and that he asked them to rush the results. No matter what the outcome of the biopsy; the tumor had to be removed, the doc said. He asked who I wanted to do the surgery. I somehow remembered that a lady I play golf with is a nurse for a gastro practice. I called her and found out who she'd ask for if she needed colon surgery. Once I got a name, I called my gastroenterologist back, told him who I wanted, and asked for an appointment. Patti deals with her diagnosis »

Colon cancer facts

• Colorectal cancer is a malignant tumor arising from the inner wall of the large intestine.
• Colorectal cancer is the third leading cause of cancer in males and fourth in females in the U.S.
• Risk factors for colorectal cancer include heredity, colon polyps, and long-standing ulcerative colitis.
• Most colorectal cancers develop from polyps. Removal of colon polyps can prevent colorectal cancer.
• Colon polyps and early cancer can have no symptoms. Therefore regular screening is important.
• Diagnosis of colorectal cancer can be made by barium enema or by colonoscopy with biopsy confirmation of cancer tissue.
• Treatment of colorectal cancer depends on the location, size, and extent of cancer spread, as well as the age and health of the patient.
• Surgery is the most common treatment for colorectal cancer.

What is cancer?

Cancer is a group of more than 100 different diseases. They affect the body's basic unit, the cell. Cancer occurs when cells become abnormal and divide without control or order. Like all other organs of the body, the colon and rectum are made up of many types of cells. Normally, cells divide to produce more cells only when the body needs them. This orderly process helps keep us healthy.

If cells keep dividing when new cells are not needed, a mass of tissue forms. This mass of extra tissue, called a growth or tumor, can be benign or malignant.

Benign tumors are not cancer. They can usually be removed and, in most cases, they do not come back. Most important, cells from benign tumors do not spread to other parts of the body. Benign tumors are rarely a threat to life.

Malignant tumors are cancer. Cancer cells can invade and damage tissues and organs near the tumor. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. This is how cancer spreads from the original (primary) tumor to form new tumors in other parts of the body. The spread of cancer is called metastasis.

When cancer spreads to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if colon cancer spreads to the liver, the cancer cells in the liver are colon cancer cells. The disease is metastatic colon cancer (it is not liver cancer).

What is cancer of the colon and rectum?

The colon is the part of the digestive system where the waste material is stored. The rectum is the end of the colon adjacent to the anus. Together, they form a long, muscular tube called the large intestine (also known as the large bowel). Tumors of the colon and rectum are growths arising from the inner wall of the large intestine. Benign tumors of the large intestine are called polyps. Malignant tumors of the large intestine are called cancers. Benign polyps do not invade nearby tissue or spread to other parts of the body. Benign polyps can be easily removed during colonoscopy and are not life-threatening. If benign polyps are not removed from the large intestine, they can become malignant (cancerous) over time. Most of the cancers of the large intestine are believed to have developed from polyps. Cancer of the colon and rectum (also referred to as colorectal cancer) can invade and damage adjacent tissues and organs. Cancer cells can also break away and spread to other parts of the body (such as liver and lung) where new tumors form. The spread of colon cancer to distant organs is called metastasis of the colon cancer. Once metastasis has occurred in colorectal cancer, a complete cure of the cancer is unlikely.

Globally, cancer of the colon and rectum is the third leading cause of cancer in males and the fourth leading cause of cancer in females. The frequency of colorectal cancer varies around the world. It is common in the Western world and is rare in Asia and Africa. In countries where the people have adopted western diets, the incidence of colorectal cancer is increasing.