by Sophia Ryzhikov

Created on: April 14, 2009

Colorectal cancer is the second most common cause of cancer deaths in the West. It is also one of the few cancers that can be detected at an early stage by screening people thought to be at risk, which can be successfully treated with surgery. Even though colorectal cancer occurs equally in men and women, it strikes women 5-10 years later than men. A high-fat, low-fiber diet, alcohol abuse, and obesity are risk factors for colorectal cancer. Also, getting regular exercise may help to prevent colon cancer.

Most people who get this type of cancer are over 60 years old, although in some cases, it occurs before 40 years of age. The cancer can occur anywhere in the colon or rectum, but about 3 in 5 tumors develop in the half of the colon nearest to the rectum. People with family history of colorectal cancer should be screened from the age of 40. An annual fecal occult blood test is advised for people over age 50 who have family history of the disease, in addition to sigmoidoscopy every 3-5 years or a colonoscopy every 10 years.

Countries where people traditionally live on a high-fiber diet consisting maninly of cereals, fruits and vegetables have low incidence of colorectal cancer, while people who consume a typical Western diet high in meat, animal fat, and low in fiber are at an increased risk of colorectal cancer. This is likely due to the fact that fiber shortens time it takes for waste matter to pass through the intestines.

As a result, potentially cancer causing substances, or carcinogens, in food are expelled at a faster rate. The risk for developing colorectal cancer is increased if a person consumes high amounts of alcohol, is obese, or doesn't exercise. Also, inflammatory disorders affecting the large intestine, such as ulcerative colitis and Crohn's disease, can increase the risk of colorectal cancer if they are long-standing.

There is a genetic component to the colorectal cancer. About 5% of all colorectal cancers are hereditary. Some people develop hereditary nonpolyposis colorectal cancer. Some patients with FAP (familial adenomatous polyposis) develop polyps, which become cancerous over time. Another gene may cause a triad of breast, ovary and colon cancers when it runs through a family. All members of the family should have regular screening for all 3 cancers.

Colorectal cancer is often diagnosed during screening before symptoms have developed. The doctor may first feel your abdomen to detect swelling. A rectal examination, in which a gloved finger is inserted into the rectum, may also be done to see if a tumor can be felt. A stool sample can be tested for the presence of blood, or a blood sample may be tested for anemia. The rectum may be examined visually with a viewing instrument through the anus, or the doctor may also order a colonoscopy, in which a flexibel viewing instrument is used to examine the entire colon. A biopsy may be taken during the procedure. You may also get a contrast X-ray in which a barium enema is used to detect an abnormality of the rectum or colon. If a cancerous tumor is detected, you will likely need to have CT scanning to see if the cancer has spread to the lymph nodes in the abdomen or to the liver.

Learn more about this author, Sophia Ryzhikov.
Click here to send this author comments or questions.