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Ask the Expert: Colorectal Cancer Screenings

All About Getting a Colonoscopy

Vivek Patil, M.D.

If you’re 50 or over, you should add colorectal cancer screening to your to-do list. A recent report from the Centers for Disease Control and Prevention (CDC) showed that screening rates aren’t where they should be (only one in three people are getting tested), despite the fact that colorectal cancer—cancer of the colon or rectum—is the second leading cause of cancer-related deaths in the United States, killing approximately 50,000 Americans per year. The good news is that it’s also one of the most preventable cancers, which is where screening comes in. So what are you waiting for? Suburban Hospital colorectal surgeon Vivek Patil, MD, explains what to expect when getting a colonoscopy, who’s at risk for colon cancer, and what you can do to lower your chances of a cancer diagnosis.

What is a colonoscopy?

Colonoscopy is a diagnostic procedure that allows the physician to examine the entire length of the large intestine. Colonoscopy can assist in identifying problems with the colon, such as early signs of cancer, inflamed tissue, ulcers, and bleeding.

An endoscope - a long, flexible, lighted tube (also called a colonoscope), is inserted through the rectum into the colon. In addition to allowing visualization of the internal colon, the colonoscope enables the physician to irrigate, suction, inject air, and access the bowel with surgical instruments. During a colonoscopy, the physician may remove tissue for further examination and possibly treat any problems that are discovered.

What should I expect before the procedure?

Prior to the procedure, your physician will explain the procedure to you and offer you the opportunity to ask questions. You will be asked to sign a consent form. You will need to fast for eight hours before the procedure, generally after midnight. If you are pregnant or suspect that you are pregnant, you should notify your physician. Let your physician know of any allergies and all medications and supplements you are taking. Mention if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.

Your physician will instruct you about specific ways to prepare your bowel for the test. You may be asked to take a laxative, undergo an enema, use a rectal laxative suppository, and/or drink a special fluid that helps prepare your bowel. Patients with certain diseases of the heart valves may be given antibiotics before the procedure. You will be awake during the procedure, but you will be given a sedative. You will need someone to drive you home afterwards. Based upon your medical condition, your physician may request other specific preparation.

What is the colonoscopy process like?

A colonoscopy may be performed on an outpatient basis or as part of your stay in the hospital if you have already been admitted for a related reason. Procedures vary depending on your condition and your physician's practices. Generally, the colonoscopy follows this process:

You will be asked to remove clothing and be given a gown to wear. An intravenous (IV) line may be inserted in your arm or hand. A sedative may be injected into the IV. Your heart rate, blood pressure, respiratory rate, and oxygen level will be monitored by an anesthesiologist during the procedure. You will lie on your left side with your knees bent towards your chest. The physician will examine the colon with the colonoscope. This may cause mild pain, pressure, and/or cramping, although the sedative should prevent you from feeling too much discomfort. If a polyp is seen, it may be removed, biopsied, or left alone until a subsequent operation is performed.

What should I expect after the procedure?

After the procedure, you will be taken to the recovery room for observation. Your recovery process will vary depending upon the type of sedation that is given. Once your blood pressure, pulse, and breathing are stable and you are alert, you will be taken to your hospital room or discharged to your home. Colonoscopy is almost always done on an outpatient basis.

You may be asked to fast for a few hours and avoid foods high in fiber content for the first 24 hours after the procedure. You may also experience flatulence (passing of gas) and gas pains after the procedure. This is normal. Walking and moving about may help to ease any discomfort.

When should I have a colonoscopy?

Colorectal cancer screening guidelines for early detection from the American Cancer Society recommend that beginning at age 50, both men and women should follow one of the examination schedules below:

  • Annual fecal occult blood test (FOBT) or fecal immunochemical test (FIT) using an at-home test kit. FOBT uses the chemical guaiac to detect blood. FIT uses antibodies to detect blood in the stool. You return the test kit to the doctor or a lab, where the stool samples are checked for the presence of blood.
  • Flexible sigmoidoscopy (FSIG) every five years (with FOBT every three years). For this test, the doctor puts a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon.
  • Double-contrast barium enema every five years
  • Colonoscopy every 10 years

Who is at risk for colorectal cancer?

  • Individuals with any of the following colorectal cancer risk factors should begin screening procedures at an earlier age and be screened more often:
  • Strong family history of colorectal cancer or adenomatous polyps in a first-degree relative, in a parent or sibling before the age of 60 or in two first-degree relatives of any age
  • Family with hereditary colorectal cancer syndromes, such as familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC)
  • Personal history of colorectal cancer or adenomatous polyps
  • Personal history of chronic inflammatory bowel disease

Has colonoscopy been shown to be effective in preventing cancer of the colon and saving lives?

Screening for colorectal cancer helps prevent this disease. Screening can find precancerous polyps (abnormal growths), so they can be removed before they turn into cancer. Screening also finds colorectal cancer early, when treatment works best.

Are there any complications from colonoscopy?

A colonoscopy poses few risks. Rarely, complications of a colonoscopy may include an adverse reaction to the sedative used during the exam, bleeding from the site where a tissue sample (biopsy) was taken or a polyp or other abnormal tissue was removed, or a tear in the colon or rectum wall (perforation).

How can I lower my risk of developing colorectal cancer?

The development of colon cancer is a complex interplay of both genetic and environmental factors. Some of the genes involved are known and identifiable, but many are still yet to be discovered.

While you cannot change your genetic risks, you can lower your risk of developing colorectal cancer by managing the risk factors that you can control, like diet and physical activity.

Most studies have found that being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Having more belly fat (that is, a larger waistline) has also been linked to colorectal cancer.

Overall, diets that are high in vegetables, fruits, and whole grains (and low in red and processed meats) have been linked with lower colorectal cancer risk, although it's not exactly clear which factors are important. Many studies have found a link between red meat or processed meat intake and increased colorectal cancer risk.

Studies show a lower risk of colorectal cancer and polyps with increasing levels of activity. Moderate activity on a regular basis lowers the risk, but vigorous activity may have an even greater benefit.

For More Information

About Dr. Vivek Patil

Dr. Patil is a board-certified colorectal surgeon associated with Johns Hopkins Community Physicians. He practices at the Johns Hopkins Health Care and Surgery Center, 6420 Rockledge Drive in Bethesda. His clinical interests include laparoscopy and minimally invasive surgery. Dr. Patil graduated from Georgetown University School of Medicine and completed his residency at Lenox Hill Hospital in New York City. He completed further surgical training with a fellowship in colon and rectal surgery at Washington Hospital Center.

For more information about gastroenterology tests and procedures, click here. If you need a referral to a gastroenterologist or colorectal surgeon, call 1-855-JHM-3939.