Colorectal cancer (CRC) — cancer that starts in the colon or the rectum — is the fourth most common cancer diagnosed in men and women in the United States, and the second leading cause of cancer death.

“Despite its high incidence, if found early, CRC is one of the most preventable, treatable and beatable forms of cancer,” BCH gastroenterologist Dennis Ahnen, MD, AGAF, FACG, said during a free health lecture held in Boulder earlier this month.

CRC often begins with benign or non-cancerous polyps, which are flat or knob-like growths on the lining of the large intestine. While some polyps remain benign, others develop into cancer over time.

“It can take 10 to 15 years for precancerous polyps to develop into CRC. Through screening, we can find these polyps and remove them before they have a chance to turn into a potentially lethal cancer,” Dr. Ahnen said. “Screening can also find the cancer in its early stages, when it’s the most curable.”

The Best Screening is the One That Gets Done

According to Dr. Ahnen, for most men and women, screening for CRC should begin at age 45 or 50 and continue until age 75. If you have a first degree relative — parent, brother, sister or children — who has had colon cancer, talk to your provider about getting screened at age 40 or 10 years before the age that your family member was diagnosed with colon cancer, whichever is earlier.

There is more than one way to get screened for colon cancer, from at-home stool blood tests, stool blood plus DNA tests, flexible sigmoidoscopy, CT colonography and colonoscopy screening.

“The advantage of a colonoscopy screening is that it can both find and remove polyps—all in a single test. Its prep can be difficult, but the preps are getting better,” Dr. Ahnen said.

Talk to your doctor about the pros and cons of the different types of screening. Each has advantages and disadvantages.

“However, the best test is the one that gets done well," Dr. Ahnen added.

Pay Attention to Your Risk Factors

Dr. Ahnen explained that both men and women have the same lifetime risk of colon cancer, which is about 5 percent. Although no one knows the exact cause of the cancer, you should pay attention to these identifiable risk factors:

  • Age over 50: Colon cancer becomes more common as people age. In fact, more than 90 percent of those with colon cancer are diagnosed after age 50.
  • Diet and lifestyle: Diets high in red or processed meat can increase your risk, as well as diets low in fruits, vegetables and fiber. Physical inactivity, obesity, cigarette smoking and heavy alcohol use have also been linked to higher risk of colon cancer.
  • Family history of polyps: If you or a family member has a history of polyps, it may put you at a higher risk.
  • Family history of colon cancer: When a first degree relative of yours has had colon cancer, you are more likely to develop this disease.

Tell Your Relatives: Family History Can Elevate Risk

Dr. Ahnen stated that roughly 10 percent of the population has a family history of colon cancer. This group has a higher than average risk for developing the disease.

He explained further: "Your colon cancer risk is related to the number of close relatives you have with colon cancer and whether any of them had colon cancer at a young age (less than 50 years). If you have a first degree relative (FDR), meaning a parent, sibling or child with colon cancer, your risk is about two-fold higher than the general population. If you have one FDR with colon cancer under the age of 50, or two FDRs with the cancer regardless of age, your risk is increased by about three-to-four fold. Finally, if you have more than two first degree relatives with colon cancer, your risk goes up eight fold compared to the general population.”

Dr. Ahnen concluded with a call to action, saying, "Reach out! If you know you have relatives with colon cancer, tell your medical provider about your cancer family history and tell your other relatives to get screened and get informed!"

Dennis Ahnen, MD, FACG, has more than 40 years experience in successfully screening for and treating gastrointestinal diseases. Appointments are available by calling Gastroenterology of the Rockies at 303-604-5000.

Click here to view PowerPoint slides from Dr. Ahnen’s lecture on "Averting the Preventable Killer - Colon Cancer."

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