Four steps you can take to prevent colon cancer

By Todd Crocenzi, M.D., oncologist, Providence Oncology and Hematology Care, and medical director, Providence Gastrointestinal Cancer Program, Providence Cancer Center

One of the things that makes cancer so frightening is that its causes are so often unknown or out of our control. With colorectal cancer, though, much is within our control. By some estimates, this form of cancer is 90 percent preventable.

So why is it still the second-leading cause of cancer deaths? One reason could be that people just aren't aware that there are steps they can take to prevent it. Let's change that.

The scientific evidence points to four actions you can take that will greatly reduce your risk of developing this deadly cancer:

  1. Take 30 minutes a day to exercise.
  2. Take a closer look at what you eat.
  3. Take another shot at quitting smoking.
  4. Take your doctor's advice about screenings.

1. Take 30 minutes a day to exercise.

Besides getting regular screenings, exercise is the most important thing you can do to prevent colon cancer. A recent analysis of 52 studies revealed that regular activity could cut the risk of developing colon cancer by 24 percent. It also lowers the risk of recurrence in people who have been treated for colon cancer.

Earlier studies have suggested that walking a few hours a week can make a difference. If you're not into walking, choose whatever activity you enjoy, start with 15 minutes, and increase your time gradually until you're up to 30 minutes or more.

2. Take a closer look at what you eat.

Accumulating evidence suggests that controlling body weight can reduce the risk of developing colon cancer. These four dietary recommendations can help control weight, and may have protective benefits as well:

  • Eat smaller portions, and less overall.
  • Eat five to six servings of vegetables and fruits every day.
  • Eat less red meat.
  • Incorporate more whole grains into your diet.

3. Take another shot at quitting smoking.

Tobacco use is now firmly established as a cause of colon cancer, increasing the risk by 25 percent. According to an American Cancer Society study published in 2009, "The incidence of colorectal cancer was significantly higher in current and former smokers compared with lifelong nonsmokers."

But there was good news in the study, too: when smokers quit, their risk declined steadily. If you've tried to quit before, try again, and take advantage of medications and support programs to increase your likelihood of success.

4. Take your doctor's advice about screenings.

A recent study found that colonoscopy – the screening that uses a scope to view the inside of your colon – may reduce colorectal cancer risk by 77 percent. This screening offers the only opportunity to find pre-cancerous polyps and to remove them before they become cancerous. Since all colon cancers start as polyps, colonoscopy gives you the chance to stop cancer before it even starts.

If the idea of colonoscopy makes you uncomfortable, be aware that there are several ways to get screened, some of which are completely noninvasive, and all of which are much better than avoiding screenings altogether. Ask your doctor about your options, and about when and how often you should get screened. Most people should start at age 50, but some people with higher risks – including African Americans, people with a family history of colon cancer, and people with Crohn's disease or ulcerative colitis – may be advised to start earlier.