Q: I just turned 50. Do I need a colonoscopy?

A: The answer is yes. Let me explain why.

Colorectal cancer is the third most common cancer in men and women. The incidence and mortality of this cancer has been declining over the past two decades due to early screening and treatment.

Your lifetime risk of getting colorectal cancer is only 5 percent, but it increases with age.

Major risk factors include family history, obesity, inactivity, smoking and heavy alcohol use.

Most physicians recommend colon cancer screening begin at age 50, depending on your family history.

Usually, screening is no longer necessary when you reach 75 to 80 years old if you’ve had no history of polyps, you’re in good general health and you have a life expectancy of at least 10 years.

There are three types of colon cancer screening:

Stool testing is done with old-fashioned stool cards (guaiac-based fecal occult blood testing) that can be checked for blood at your physician’s office.

If you and your doctor choose this screening, it should be done annually; however, it has the highest risk of missing a cancer, and it has a high rate of false positive results.

A newer, more accurate stool test is called Cologuard, which detects specific precancerous markers.

Medicare covers Cologuard at 100 percent, and many commercial insurance plans are now covering it, as well. Cologuard should be performed every three years.

If any stool test is positive, a colonoscopy should be performed.

Imaging involves colonography, which is a detailed CT scan of the colon. It shows any existing polyps but might miss small precancerous polyps.

This screening includes radiation exposure.

Insurance coverage for colonography varies, and recommendations on how often to use this test are not clear.

If your colonography is positive, a colonoscopy would be recommended.

Procedure-based screenings include sigmoidoscopy and colonoscopy.

Most doctors prefer colonoscopy because it provides a view of your entire colon and any precancerous or cancerous polyps.

A colonoscopy is usually recommended every 10 years in patients with no history of polyps or a family history of colon cancer.

It should be performed more frequently if you have a positive history. Most insurance plans cover this procedure if it is done at the recommended times.

The U.S. Preventive Services Task Force’s 2016 guidelines do not emphasize any one specific screening method, as long as you are screened.

However, colonoscopy is still the gold standard for screening because it gives the best overall exam of the colon for precancerous lesions and polyps.

Discuss with your physician which screening test is best for you.

Dr. William E. Kyle is an internal medicine physician at Memorial Health University Physicians – Legacy Center in Okatie.