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Closing the Door on Colon Cancer

Here are the facts: Colorectal cancer is the second leading cause of cancer death in the United States, and the leading cancer killer among non-smokers. In 2005, the American Cancer Society estimates that over 145,000 new cases will be diagnosed in the U.S., and over 56,000 men and women will die from colorectal cancer. Michigan alone will account for more than 4,800 of those estimated new cases and approximately 1,900 of those deaths.

Yet one overwhelmingly hopeful fact stands in stark contrast to these frightening statistics:The vast majority of colorectal cancer deaths are preventable by screening and early detection. If that's the case, why doesn't everyone take steps to be screened for colon cancer? For an answer, Progress turned to D. Kim Turgeon, M.D., F.A.C.P., clinical associate professor in the Department of Internal Medicine at U-M to provide some background on the disease, define who's at risk and describe what's involved in screening.Turgeon did all that and more: she also gave every Progress reader the chance to take part in her latest prevention outreach initiative: The Polyp Pest.

Colon Cancer's Causes

Colon cancer actually refers to cancer of the large intestine or large bowel, which is made up of the colon and the rectum, or colorectum. Science is still grappling with the exact causes of the disease, but it is known that nearly all (95%) of colorectal cancers begin as a particular type of polyp called an adenoma. It is thought that mutations in specific genes eventually cause normal cells in the lining of the colon to develop polyps. Eventually, the accumulation of more mutations in specific genes can turn these adenomas into cancers. Most polyps in the colon are benign. Not all polyps are adenomas that can turn cancerous. Identifying and removing polyps to prevent the development of colorectal cancer is the purpose of a colonoscopy.

Risk Factors
More than 90% of colon cancer cases occur in people (men and women equally) age 50 and older, making age the No. 1 risk factor for the disease. There are, however, other risk factors to consider:

  • Family history of colorectal cancer or adenomas
  • Cigarette Smoking -- which can increase the risk of colon cancer death by 30%-40%, perhaps accounting for up to 12% of colon cancer fatalities
  • Obesity
  • Sedentary lifestyle
  • High fat diet, especially one from mostly animal sources
  • Heavy alcohol intake
  • Ulcerative colitis or Crohn's colitis
  • Cancer of the uterus or ovaries before age 50
  • Past removal of the gallbladder
  • Past radiation of the abdomen
  • Diabetes-- increasing the risk of developing colorectal cancer 30%-40%

Turgeon cautioned that the absence of these additional risk factors is no excuse to avoid screening. "Very significant risk develops because of age alone," she reminds us.


Symptoms of colon cancer include rectal bleeding, anemia, a change in bowel habit, abdominal pain and weight loss. But unfortunately, notes Turgeon, "these symptoms are common and often do not signal colorectal cancer. Worse yet, when they are caused by cancer, they often represent the disease in its late stage."


As Turgeon notes, this form of cancer nearly always develops from adenomas in the colon and rectum. Screening tests can find these polyps, making it possible to remove them before they turn into cancer, as well as finding colorectal cancer early, when survival rates are highest. "Colorectal cancer has four stages," she explains. "Stage one cancers are confined to the inner lining of the colon and first layer underneath it.When these are found and removed, there is a survival rate of more than 95%. Stage two tumors have spread into or through the muscle layer of the colon but do not involve the lymph nodes -- catching the cancer here results in an 80% survival rate. At stage three, tumors involve the lymph nodes adjacent to the colon, and the survival rate decreases to about 50%. At the final stage, the tumors have spread to distant organs, most commonly to the liver, and the survival rate is about 5%. Clearly, the ability to see and remove precancerous polyps and cancerous tumors early is the key."

In fact,Turgeon considers one screening tool, the colonoscopy, to be the most powerful prevention tool in clinical medicine, since it can both identify and remove precancerous polyps. Other colon cancer screening tools include the fecal (stool) occult blood test with flexible sigmoidoscopy and the double contrast barium enema.Together they comprise a powerful arsenal in the war against colon cancer.

For people at average risk, current recommendations call for screening to begin soon after one's 50th birthday, then continuing at regular intervals. Individuals should discuss screening options with their physicians to determine whether they fall into an elevated risk group requiring testing to begin before age 50. The doctor and patient together can also decide which test to pursue and when the test should be repeated.

"Currently, although awareness of colon cancer is increasing, rates for screening remain below those of breast, cervical and prostate cancer, even though the evidence is so strong to support getting tested," says Turgeon. Why? She believes many adults, thinking they have no symptoms, don't realize they are at risk. "Once symptoms are present, it's a whole new situation. Half of those who are diagnosed after symptoms have developed will die from this cancer.That's why it'Ts so important to be screened before symptoms show up."

Of course, there are other barriers to overcome. "People are uncomfortable discussing that part of the body, and they're also fearful of the test." As Turgeon notes, for most patients, the test itself is not difficult. Performed under conscious sedation, it results in little if any pain. But the bowel preparation necessary prior to the test can be quite uncomfortable, requiring frequent trips to the bathroom. "That's why we need to work harder to address these concerns and help patients take charge of their own health." To do so,Turgeon and her colleagues at the U-M Cancer Center have launched a unique program to encourage people to get a screening colonoscopy, and to persuade those they care about to do the same.

The Polyp Pest

Turgeon's team designed the Polyp Pest, a special bathroom door hanger to put to use when preparing for a colonoscopy. "We realized that when it comes to encouraging colon screening, sometimes you just need to be a pest. Although it sounds crazy," explains Turgeon, "we have a serious purpose in mind. In addition to providing people with a friendly reminder of the importance of colorectal cancer screening for themselves, we also want to give them something they can easily pass along, encouraging someone else to get screened too.We've included a toll-free phone number and web address hoping that everyone who receives it will contact us and let us know anonymously whether they were screened, and whether they passed along the Polyp Pest."

Over a six-month period, approximately 40,000 Polyp Pests will be distributed. Their "paths" will be tracked over the course of a year to determine whether information, paired with a little friendly pestering, can make a difference.


To learn more about Colon Cancer, or for help finding a doctor near you, call the Cancer AnswerLine™ at 800-865-1125.

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This article is part of the Cancer Center's News Archive, and is listed here for historical purposes.

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