How to Prevent Colorectal Cancer

Colorectal cancer is the second most common cause of cancer and cancer death in American men and women. Approximately one out of every 18 people will develop colorectal cancer in their lifetime.

Is colorectal cancer preventable?
Unfortunately, half of people who get colon cancer will have disease that is at an advanced stage. When colorectal cancer is found at an advanced stage, the chance of cure is much less than when it is detected early. Fortunately, colorectal cancer is preventable by having regular checks of the colon called screenings. Colorectal cancer forms from polyps, called adenomas. If adenomas are found and removed before they grow large and turn into cancer, cancer is prevented. Even if cancer is found, it is curable in over 90% of patients if caught early. Most polyps and curable cancers do not produce symptoms. Therefore, do not wait for symptoms to develop, see your doctor for colon checks on a regular basis while you are feeling well.

Who is at risk of colorectal cancer?
We are all at risk of developing colorectal cancer. Over 75% of patients who get colorectal cancer have no identifiable risk factors. They are a group of patients called average risk. The remainder of patients either has a personal history of colorectal polyps or cancer, ulcerative or Crohn's colitis, or a strong family history of colorectal cancer. These patients are at moderate to high risk. When we say a strong family history we mean a family that contains multiple relatives or first-degree relatives (parent, brother/sister, or child) with colorectal cancer. The risk is particularly strong if the first degree relative with cancer was less than age 50.

Colorectal cancer screening to detect cancers and precancerous adenomatous polyps in average risk patients is encouraged by at least three expert groups. All screening options are not acceptable for patients with symptoms that could be consistent with colorectal cancer or patients at moderate or high risk. Symptoms of colorectal cancer include a change in bowel habits, abdominal pain, rectal bleeding or anemia. Patients with symptoms or at moderate to high risk should have an examination of the whole colon called colonoscopy.

Average risk:
People with no symptoms or any of the risk factors in moderate or high-risk group are considered average risk at developing colorectal cancer. These people should be screened for colorectal cancer starting at age 50.

Recommendations: (Options include either)

Fecal blood testing (FOBT) every year
This is a test on smears of stool. It can detect microscopic blood by a chemical reaction. Patients should be on a specialized diet before this test is performed to try to minimize falsely positive or negative tests. The restrictions include:

• No red meat, poultry, certain raw vegetables and melons
• No anti-inflammatory medications or aspirin for 7 days
• No vitamin C (or multivitamins with vitamin C)

The test is positive if any of six windows change to a blue color. If it is positive, a colonoscopy should be performed.

Flexible sigmoidoscopy every 5 years
This is a test where a physician passes a thin, flexible tube into the lower colon and examines the lining. It is done in addition to the yearly fecal occult blood testing. If an adenoma is found during the flexible sigmoidoscopy, a colonoscopy should be performed to remove the polyp and search for polyps higher in the colon. It is recommended that flexible sigmoidoscopy be combined with an annual FOBT.

Barium enema plus sigmoidoscopy
A barium enema is an x-ray. It is not accurate enough to check for colorectal polyps and can even miss cancers. It should not be used for colorectal cancer screening unless a colonoscopy cannot be performed. If it is used, it should be coupled with a flexible sigmoidoscopy to see the part of the lower colon that is not well seen on x-ray.

Colonoscopy every 10 years
Colonoscopy is a test where the doctor inserts a thin flexible tube into the complete colon. If the examination is normal, this test is done every 10 years. Colonoscopy is the preferred colorectal cancer screening test. It is also the test of choice if patients have any symptoms that could be suggestive of colorectal cancer such as intestinal bleeding, unexplained abdominal pain or change in bowel habits. No additional FOBT or sigmoidoscopy should be done between colonoscopy examinations. If any polyps are seen during the exam, they should be removed and sent to the laboratory for analysis. If adenomas are found, generally follow up colonoscopy is performed in 3 to 5 years. Many patients with adenomas require lifelong colonoscopy at 3 to 5 year intervals.

Moderate risk:
Those people at moderate risk of developing colorectal cancer have a personal history of adenomatous polyps or colorectal cancer; one first degree relative (parent, child or sibling) with colorectal cancer or adenoma < 50 years of age; or more than 1 first degree relative with colorectal cancer at any age.

Recommendation:

• Colonoscopy every 5 years
• Start at age 40, or 10 years before the youngest case in the family, whichever is earlier

High risk:
Those people with an inherited predisposition to colorectal cancer such as familial adenomatous polyposis (FAP) or Hereditary Nonpolyposis Colorectal Cancer (HNPCC) are considered at high risk for developing colorectal cancer. They and their family members should be seen by a team of experts familiar with the diagnosis and treatment of these disorders.

Familial adenomatous polyposis (FAP)
Recommendation:

• Flexible sigmoidoscopy or colonoscopy every 6-12 months. Start in puberty
• Refer to Medical Genetics at (216) 445 5686, the High Risk Clinic and Inherited Colorectal Cancer Registry at (216) 444-6470

Hereditary Nonpolyposis Colorectal Cancer (HNPCC)
These are families with colorectal cancer in at least three relatives, one first-degree relative of other two, and occurring over two generations. At least one relative must be diagnosed with colorectal cancer < 50 years of age. These families may also have uterine, ovarian or other gastrointestinal or urinary cancers.

Recommendation: 

• Colonoscopy every 2 years until age 40; then every year. 
• Start at age 25 or 10 years younger than the youngest case in the family.
• Pelvic Ultrasound and endometrial biopsy every year beginning at age 25.
• Refer to Medical Genetics at (216) 445 5686, the High Risk Clinic and Inherited Colorectal Cancer Registry at (216) 444-6470

Inflammatory bowel disease (Crohn's or ulcerative colitis)
People with inflammatory bowel disease (IBD) should have a colonoscopy with biopsy for dysplasia every 1-2 years. Colonoscopies should start 8 years after the onset of symptoms if the whole colon has been inflamed (pancolitis) and 12 years after the onset of symptoms if only the left-side of the colon has been inflamed.