Open Accessibility Menu

Dr. Matthew Karowe: 'Colorectal Cancer is Preventable'

Dr. Matthew Karowe: 'Colorectal Cancer is Preventable'

Excluding skin cancers, colorectal cancer (CRC) — cancer that starts in the colon or the rectum — is the third leading cause of cancer-related deaths in the United States. It is also the third most common cancer in men and women.

"This cancer is extremely common and lethal. The good news is that it’s preventable,” said board-certified gastroenterologist Matthew W. Karowe, MD, of Gastroenterology of the Rockies during a free online lecture.

“In fact, we have made significant strides in preventing CRC and CRC-related deaths. In 2000, deaths decreased significantly in those older than 50. This coincided with the increase in CRC cancer screenings,” said Dr. Karowe.

Throughout his presentation he explains how to reduce your risk of and potentially prevent CRC.


VIDEO: Watch Dr. Karowe's online lecture on preventing colorectal cancer.

What is Colorectal Cancer?

Our colon and rectum make up our large intestine (or large bowel) and are a part of our digestive system. Colorectal cancer is a cancer that begins in the colon or rectum.

The cancer will begin as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the colon. “Over time,” explained Dr. Karowe, “some of these polyps can grow and become cancers. It has a clear progression from a normal cell, to a polyp, to a cancer.” He added, “We estimate that it takes 10 to 15 years for an abnormal cell to grow into cancer. This is why we can schedule colonoscopies at 10-year intervals.”

The Stages of Colon Cancer

  • Stage 1—is the earliest stage. At this point the cancer is contained within the colon and it’s not spreading. For stage 1 we can expect 80 to 95 percent of patients to survive five years from the diagnosis.
  • Stage 2—is when the cancer extends into the layers of the colon wall, but it still has not spread significantly.
  • Stage 3—is when we unfortunately see that the cancer has spread to the patient’s lymph nodes.
  • Stage 4—is when the cancer has metastasized. This means the cancer cells are spreading to the liver, lung or elsewhere. For stage four, the five-year survival rate decreases to less than five percent.

Colorectal Cancer Risk Factors

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

Family history

According to Dr. Karowe, family history is by far the most important indicator of colorectal cancer risks. If you have a first degree relative (parent, sibling, child) who has had CRC at any age, your risk is about two-and-a-half times more than for the general population. And, if that relative was younger than 50 years, your risk can be as much as four times more.

“The more relatives you have who have had CRC and/or if you have a heredity abnormality, the greater your risk is for getting the cancer,” Dr. Karowe noted. “As your risk increases so too does the intensity of screening so that we can help to prevent this disease.”

Other risks include:


  • Being obese or overweight
  • Not getting enough physical activity: “We recommend 30 minutes of physical activity each day,” said Dr. Karowe.
  • Smoking
  • Alcohol consumption—even mild to moderate
  • Diet
    • Eating too much red/processed meat
    • Not getting enough daily fiber
    • Not eating enough of fruits and vegetables

Age over 45

CRC becomes more common as people age. Studies show rates of colorectal cancer among people younger than 50 years are on the rise. As a result, experts have determined that screening starting at 45 years could help save more lives.

Failing to Get Screened

“Far and away the biggest risk factor for developing and dying from colorectal cancer,” said Dr. Karowe, “is failing to get screened. Screening is essential for detecting early cancer and potentially preventing it from developing.”

At What Age Should You Get Screened?

Screening guidelines for those at average risk for colorectal cancer

The American Cancer Society (ACS) has guidelines for CRC screening and recommends people at average risk for colorectal cancer begin screening at age 45. (Average risk means you have no personal family history of polyps or cancers or inflammatory bowel disease.)

Dr. Karowe noted, “In the past, age 50 was the recommended age to begin screenings. However, we are seeing cancers and polyps increasing for this younger age group. Experts have determined that screening starting at 45 could help save more lives.”

Screening is recommended to continue to age 75, with screenings for those between ages 76 to 85 individualized, depending upon health status, family history and history of polyps.

Screening guidelines for people at higher risk for colorectal cancer

If you have a first degree relative — parent, brother, sister or children — who has had colorectal 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. Dr. Karowe added, “The more relatives that you have who have been diagnosed with colorectal cancer, the more often you should be screened.”

Individuals with certain hereditary syndromes will develop polyps and cancers at much younger ages and will want to start their annual screening much earlier, as young as 12 to 25 years old.

‘The Best Screening is the One That Gets Done’

There is more than one way to get screened for CRC.

  • Stool screening tests. According to Dr. Karowe, stool-based screening tests can help identify large polyps and cancers. “However, they are less sensitive and less specific than other tests. They are not great for identifying small or moderate polyps. They can miss a lot and have a high incidence of false positives.” he said.

    There are three types of stool tests that Dr. Karowe describes in detail in his lecture. He said, “Generally, the fecal immunochemical test (FIT) and Cologuard® are all equal. If the screening test comes back positive, your health care provider will recommend that you schedule a diagnostic colonoscopy.”
  • Sigmoidoscopy. This is a visual examination; however, it only provides imaging of the left side of the colon. It’s Dr. Karowe’s opinion that the colonoscopy is the better option for screening, as it provides a more complete picture of your colon’s health.
  • Computer Tomography (CT or CAT scan) Colonography. This is a CAT scan; it does use radiation and requires the same prep as for a colonoscopy. “The benefit of this test is we can see everything outside of the colon and it also sees other organs,” said Dr. Karowe. He added, “If an abnormality is identified, a colonoscopy would be recommended as the next step.”
  • Colonoscopy. A colonoscopy is a visual examination that evaluates the entire inside of the colon. “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. Karowe said.

Current Insurance Coverage

Colorado follows the U.S. Preventive Services Task Force (USPSTF) guidelines that recommend screenings starting at 50 years old. Dr. Karowe explained, “This means your insurance may not cover your CRC screening if you are younger than 50.” Dr. Karowe does believe this will be changing and that those 45 years and older will be covered in the future.

Dr. Karowe ended his lecture as he had started it. He emphasized that colorectal cancer is common, lethal, but most importantly preventable. He urges everyone to get screened and said, “Any type of screening will decrease our incidence of CRC and deaths related to CRC.”

Visit the Gastroenterology of the Rockies website for more information or call (303) 604-5000 to schedule an appointment with Matthew W. Karowe, MD.

Click here to view/download a PDF of slides shown during Dr. Matthew Karowe’s BCH lecture “Colon Cancer—The Preventable Killer.”