Colorectal Cancer: Understanding Risk Factors and Screening

Colorectal cancer is the third most common cancer in the United States and occurs most often in people over the age of 50. Cancer screening can help find colorectal cancer to help treat it as soon as possible. This fact sheet covers:

• Risk factors for colorectal cancer
• Why colorectal cancer screening is important
• Colonoscopy and other testing methods

What Are Some of the Risk Factors for Colorectal Cancer?

A risk factor is anything that raises your chances of developing cancer. The following are some of the known risk factors for colorectal cancer and mean you should likely get screened.

Age. Colorectal cancer is more common in people over the age of 50.

Personal and family history. People who have a parent, sibling or child with colorectal cancer are at a higher risk of developing it themselves, especially if the family member was diagnosed before the age of 60. If you have had colorectal cancer, you are at a higher risk of the cancer returning. People with personal or family history of colorectal polyps are also at increased risk of colorectal cancer.

Race. Black and African American individuals are at higher risk. The reasons for this are not yet fully understood.

Jews of Eastern European descent. About 6% of American Jews who are of Eastern European descent have DNA changes that increase their risk of colorectal cancer. For more information, ask your doctor about comprehensive biomarker testing, which may include genetic testing for inherited cancer risk.

Why Is Screening for Colorectal Cancer So Important?

Many colorectal cancers can be prevented through regular screening. Screening can find precancerous polyps—abnormal growths in the colon or rectum—so that they can be removed before they turn into cancer. Screening is important because when found early, colorectal cancer is highly treatable.

Early stages of colorectal cancer usually present no symptoms. This means that only screening can find the cancer, if present. Symptoms tend to appear as the cancer progresses.

Colonoscopy and Other Screening Tests

A colonoscopy is the best and only screening test that can detect many colorectal cancers. Here are a few things you should know about colonoscopies:

• During a colonoscopy, your doctor examines the lining of your entire colon to check for polyps or tumors. If any polyps are found, they can be removed immediately.

• Your doctor performs a colonoscopy by inserting a long, flexible tube into your colon through the rectum with a tiny video camera and light at the end.

• Before the procedure, you will receive instructions from your doctor on what to eat and how to empty your bowels.

• On the day of the colonoscopy, you will receive medication to help you relax. Most people fall asleep and do not remember much about the test when they wake up.

• It is usually recommended to start having colonoscopies at age 45, regardless of gender. People at increased risk may start earlier, depending on your doctor’s instructions.

If you are unable to have a colonoscopy, your doctor can give you information about alternate tests and how often they should be performed, including a sigmoidoscopy, double contrast barium enema, fecal occult blood test or DNA stool tests. These are not as thorough as a colonoscopy and if polyps or tumors are found, you will still need to have a colonoscopy.