Factors that determine the outcome of colonoscopy

Colonoscopy is the most effective test for the detection and prevention of colon cancer, the 2^nd leading cause of cancer death in the United States. In a study published in the New England Journal of Medicine in 2012, removal of polyps during colonoscopy led to a 53% reduction in colorectal cancer death.

Colonoscopy utilizes a flexible tube with light and camera at the end to look at the inner lining of a person’s large intestine (colon) through a video monitor.

Before the procedure, an informed consent is obtained by the physician from the patient or an adult caregiver if the patient cannot give one.

Colonoscopy can be done without sedation; with minimal sedation; with moderate sedation; with deep sedation or with general anesthesia.

During the procedure, the physician has the ability to take a small piece of tissue from the colon (biopsy), remove a polyp (polypectomy), mark a specific spot (tattoo), treat a blockage, or stop a bleeding. Any tissue or specimen removed during colonoscopy is sent to the pathologist for analysis. Pictures are taken during the procedure and a colonoscopy report with pictures is generated.

Three essential factors determine the outcome of a colonoscopy: The patient, the prep, and the physician.   

The 1^st P is the patient.

The patient is at the center of healthcare.

The patient should have three characteristics:

• Be able (or through a surrogate) to consent for the procedure.
• Be in a relatively stable condition for colonoscopy.
• Have a reason (indication) for colonoscopy.

These are some of the reasons for having a colonoscopy:

• Screening and surveillance of colorectal polyps and cancer.
• Evaluation and treatment of gastrointestinal bleeding.
• Evaluation of abnormalities seen on imaging studies such as X-ray or CT scan.
• Evaluation of change in bowel habits like unexplained diarrhea.
• Evaluation of unexplained abdominal pains.
• Evaluations of inflammatory bowel disease (ulcerative colitis or Crohn’s disease)
• Management of complications of surgery like strictures, leaks, fistula.
• Removal of foreign body from the colon.
• Excision and ablation of colorectal lesions such as angiodysplasias.
• Relief of colorectal obstruction.

The 2^nd P is the prep.

The colon needs to be prepared for a colonoscopy. It has to be cleaned out so that the physician can properly see the inner lining of the colon. This is called bowel preparation.

The adequacy of bowel cleansing is scored during colonoscopy using several bowel preparation scales. Adequate bowel prep is one that can detect polyps 5mm in size or more.

Inadequate bowel prep is associated with a reduced chance of detecting pre-cancerous polyps. It leads to longer procedure time and aborted procedure. Ultimately, it leads to higher healthcare cost.

There are many medications approved by the Food and Drug Administration as bowel cleansing agents. These include Colyte®, GoLYTELY®, NuLYTELY®, TriLyte®, HalfLytely®, MoviPrep®, SUPREP®, OsmoPrep®, and Prepopik®.

Regardless of the bowel cleansing agent used, the split dose regimen has been proven in multiple studies to be the most effective way to use the medication. In the split dose regimen, half of the bowel cleansing agent is taken the evening before the colonoscopy. The 2^nd half is taken 4-5 hours before the scheduled colonoscopy.

Bowel preparation is often the most unpleasant aspect of colonoscopy. Certain tricks can improve a patient’s experience of bowel preparation:

• Chill the bowel cleansing liquid. A cold cleansing liquid is easier to swallow than a warm one.
• Improve the taste of the cleansing agent by adding flavor with lemon juice, lemon slices or sugar-free flavor enhancers like Crystal Light®.
• Use a straw to drink the bowel cleansing agent to reduce exposure of the taste to the tongue.
• Suck on a menthol candy like Halls® cough drops while drinking the bowel cleansing agent. This has been shown in studies to improve taste and bowel preparation.

The 3^rd P is the physician

The training and competency of the physician is important in reaping all the benefits of colonoscopy. Certain quality measures have been established to assess the effectiveness of the endoscopist.

Perhaps the most important of these measures is the adenoma detection rate. This is the rate at which a physician detects pre-cancerous polyps in average risk individuals presenting for screening colonoscopy. According to a study published in the New England Journal of Medicine in 2014, each 1% increase in the adenoma detection rate was associated with a 3% decrease in colorectal cancer.

A task force on quality in endoscopy from the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy proposed the following quality measures for physicians:

• Detect pre-cancerous polyps in average risk persons presenting for screening colonoscopies in 25% or more of cases (30% for men; 20% for women; 25% for both).
• Spend at least 6 minutes when withdrawing and inspecting the colon in patients with a negative screening colonoscopy.
• Complete the procedure by reaching the start of the colon (cecum) in at least 95% of all screening examinations.
• Have less than one in a thousand patients with a complication of perforation in screening colonoscopies; and less than 1% of patients with bleeding after colonoscopy.

Beside these quality measures, a good bedside manner and a caring heart are important.

Colonoscopy is a life-saving procedure but often dreaded and misunderstood.

To get the most out of colonoscopy, remember the 3 Ps.

Adewale Ajumobi is a board certified gastroenterologist. This article originally appeared on www.bowelprepguide.com.