Colonoscopy Myths: What’s the Truth?

A colonoscopy is a common procedure that lets doctors examine the colon and rectum for abnormalities and changes. It’s often used as a screening tool for colorectal cancer, the fourth leading cause of cancer-related deaths in the United States according to the American Cancer Society. Routine testing can help prevent colorectal cancer or find it at an early, easily treatable stage.

Current guidelines state you should have your first colonoscopy at age 45 and one every 10 years thereafter if you have no special risk factors for colorectal cancer. If a relative has had colorectal cancer, or if you have an inflammatory bowel disease such as Crohn's disease or ulcerative colitis, a genetic risk such as Lynch syndrome, or an inherited polyposis syndrome, you may need screenings earlier or more often.

Many people avoid colonoscopies for various reasons. Unfortunately, this means only 4 out of 10 people are being diagnosed with colorectal cancer in its early stages. According to the American Cancer Society, the five-year survival rate is 90% for people whose colorectal cancer is found and treated early. So there’s a big benefit to being tested and catching any precancerous and cancerous lesions as soon as possible.

Benjamin Yip, M.D., a gastroenterologist and interventional endoscopic specialist with Sutter, says people who are candidates for the test will often put off scheduling one because they’re fearful of the procedure and have misconceptions about colon cancer.

“People may not realize that colorectal cancer is one of the most preventable cancers and that a colonoscopy could save their life,” Dr. Yip says. “A colonoscopy is unique in that we’re not only able to find early cancers but can also prevent colorectal cancer. The vast majority of polyps identified during the colonoscopy can be removed at the time they’re found, so the patient doesn’t have to come back for another procedure.”

Here are some of the common concerns and myths associated with colonoscopies:

Myth: I don’t have time for a colonoscopy.

Medical appointments do take time out of your routine, but they’re important to maintain good health. Reading more about colonoscopy preparation and timing can help you plan. The procedure itself is fairly quick. It takes about 20 to 30 minutes to complete, followed by another 30 minutes in the recovery area. Often, the entire appointment takes two hours or less.

Myth: A polyp means I have cancer.

A polyp is actually a noncancerous (benign) growth that can develop anywhere in the large intestine. Over time, these growths can develop into colorectal cancer. Polyps are easily removed during a colonoscopy by using an endoscope, a flexible tube with a tiny video camera and light at the tip, and small surgical tools. These polyps are often sent to a laboratory for testing after removal.

“Polyps are very common. At least 1/4 of people who have colonoscopies have polyps. They’re the precursors to colorectal cancer. The idea is to identify these polyps and remove them, reducing the risk of colorectal cancer,” Dr. Yip says.

Myth: I don’t have symptoms, so I don’t need a colonoscopy.

Colon polyps often don’t cause any symptoms. It’s not until they’ve transformed into full-blown colorectal cancer that symptoms may arise. The whole point of a colonoscopy is to remove these polyps before they become cancerous. Schedule an appointment with your doctor if you have rectal bleeding, bloody stool, black stool, prolonged constipation or diarrhea, lower stomach cramping, the frequent urge to have a bowel movement or unintentional weight loss, as these are all possible signs of underlying colon issues. You should talk to your doctor if you have a family history of colon cancer, which could mean you need to begin colonoscopies earlier.

Myth: The preparation solution is too hard to drink.

Until recently, patients were asked to drink a gallon of preparation solution, which induces bowel movements to clean out the colon. Drinking that much liquid can be challenging, but these days it’s standard for a patient to drink one quart of prep solution the night before and a second quart of prep the morning of the procedure. There are four quarts in a gallon, so the new standard requires half the volume of the traditional cleanse.

“If needed, we can even use smaller volumes of the preparation solution. For those who can’t drink fluids, we have pills that can be taken to clean out the colon,” Dr. Yip says.

As far as dealing with the typically salty taste of the prep solution, Dr. Yip suggests mixing it with 7UP, ginger ale, Gatorade or Crystal Light to make it more palatable. He stresses that it’s very important to finish all of the preparation solution and to take it as instructed. Research suggests doctors could miss precancerous growths in patients who don’t properly prepare because stool left in the colon can block the scope’s view.

Myth: It’s too painful.

During a colonoscopy, your doctor inserts a flexible tube with a tiny video camera at the tip into the rectum and colon. This allows your doctor to visually inspect your colon for precancerous or cancerous lesions. You may feel some pressure and cramping, but you’ll be given medication to make you sleepy and comfortable.

“We use sedatives during the procedure and the great majority of patients wake up having no idea that the procedure was done,” Dr. Yip says. “Luckily, the colon has no nerve endings on the inside, so removing polyps doesn’t cause any pain.”

Myth: The risks of colon perforation and bleeding outweigh the benefit.

A colonoscopy is a safe procedure, but in rare cases the endoscope can puncture the wall of the colon or rectum, creating a perforation. This complication usually requires surgery for treatment. Dr. Yip says studies have shown that the risk of perforation is less than one in every 10,000 patients, or less than 1/10 of 1%.

Rectal bleeding may occur rarely at the site of a biopsy or where a polyp was removed, but it’s usually very minor and goes away after a few days. If the bleeding is severe and persistent, it’s important to contact your doctor right way.

Myth: Colorectal cancer only affects men.

Colorectal cancer affects both men and women. Each year more than 150,000 people across the nation are diagnosed with colorectal cancer and more than 50,000 die from the disease, according to the CDC. Dr. Yip says the notion that this cancer only affects older men is simply untrue.

“People often mistake colorectal cancer for prostate cancer. Women need to have colonoscopies just as regularly as men,” he says.