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Colorectal Cancer Awareness: Colonoscopy

March is Colorectal Cancer awareness month. To help raise awareness of this condition, we will be sharing guest blogs by gastroenterologist Dennis J. Ahnen M.D., AGAF, FACG of Gastroenterology of the Rockies.

Colonoscopy: What to Expect and Tips for Your Procedure

A colonoscopy is central to the care plan for families with hereditary colorectal cancer (CRC) syndromes. Colonoscopic screening is the major means for prevention and early detection of CRC. The main goals of a screening colonoscopy are the early detection of CRC while it is still curable or, better yet, prevention of CRC by detection and removal of pre-cancerous polyps. However, colonoscopies and colonoscopists are not equal, as there is surprisingly high variability in the quality of a colonoscopy.

Achieving a high-quality colonoscopy requires a joint effort by the patient, the endoscopist and the endoscopy unit. There is general agreement about important metrics for a high-quality colonoscopy, which include elements that occur before, during and after the procedure.


Prep is critical to identify and completely remove colonic polyps, as this requires good visualization of the entire colonic mucosa. A high-quality endoscopy suite is expected to have good to excellent quality preps for more than 85% of all colonoscopies. There are numerous colonoscopy preps available but, unfortunately, they all induce dramatic diarrhea.

The prep is generally considered the most unpleasant part of the exam. Better cleansing is obtained by using a split dose prep (half the night before, half the day of the procedure). Other pre-procedure quality metrics include an appropriate indication for the colonoscopy and proper informed consent for the procedure.

What should you expect pre-procedure?

  • Diarrhea and sleep disturbance.
  • Detailed information/instructions for the recommended prep including dietary restrictions, a description of what you will likely experience and the side-effects that can arise (dehydration, vomiting).
  • To be offered the option of a split prep.
  • To learn whether you need to change any of your medications/supplements prior to the examination.
  • Which type of sedation will be used and the need to arrange for transportation.
  • You should be able to find out how much the procedure will cost and how much of that you will be expected to pay.

Tips for pre-procedure

  • Get the prep kit several days prior to your scheduled procedure and read and follow the instructions carefully. You don’t want to have a poor-quality examination or to have to do the prep more than once.
  • Accept a split prep when offered or ask about it if it’s not offered.
  • Preps vary substantially in volume, palatability, and cost. Ask about your options.
  • Propofol anesthesia is preferred over conscious sedation with drugs like fentanyl and versed by many endoscopists (and patients) but it must be administered under the direction of an anesthesiologist. It doesn’t improve the quality metrics of the examination and it can add $500-$2,000 to the overall cost of the procedure.
  • The Affordable Care Act requires insurance companies to cover the cost of screening colonoscopies without copays but if a polyp is found or if the test is done to evaluate symptoms or as a second step after another type of screening test, it may be classified as a diagnostic examination and, depending on your insurance coverage, you may receive a substantial bill.

During the Procedure

The single most important component of a high-quality colonoscopy is a performance by a high-quality colonoscopist; one with a low interval CRC rate (ICR). Although it currently isn’t feasible to routinely measure ICRs, another more easily measured metric, the adenoma detection rate (ADR), strongly correlates with the ICR. The ADR is the percent of average-risk patients undergoing a screening colonoscopy who are found to have one or more colonic adenomas. This is arguably the single most important metric of a high-quality colonoscopist; the minimal acceptable ADR is 25% (20% in women, 30% in men).

In general, higher ADRs are found in providers who have had more endoscopic training and those that do more colonoscopies. As a group, gastroenterologists and colorectal surgeons have more extensive training, do more colonoscopies and have higher ADRs than internists or general surgeon colonoscopists but there are certainly exceptions to this generalization. ADRs can be improved through education and training.

Additional metrics of a high-quality colonoscopist are a high rate of examinations that are complete to the cecum (>95% for screening exams with good preps), an adequate amount of time examining the mucosa on the way back from the cecum (average > 6 minutes) and a low complication rate (serious complications <1/1,000 procedures).

What should you expect during the procedure?

  • A colonoscopy done by a high-quality colonoscopist.
  • The colonoscopist should be well-trained, perform enough colonoscopies to maintain technical expertise (some suggest >200/year) and have an ADR of over (preferably well over) 30%.
  • A high-quality colonoscopist should know and be willing to provide you with his/her training, colonoscopy volume and ADR.
  • The colonoscopy should be complete to the cecum and adequate time should be taken to carefully examine the colon.

Tips for during the procedure

  • Colonoscopy is highly effective but it is not perfect. The miss rate for CRCs is estimated to be 2-6% overall and even high-quality endoscopists occasionally miss CRCs. The miss rate for precancerous polyps is higher.
  • Colonoscopy is safe but serious complications such as perforations and bleeding do occur rarely (<1/1000 procedures).
  • Colonoscopy is expensive. In a highly publicized (and criticized) article, the NY Times reported costs as high as $4,000-$8,500 in cities across the country.


Quality metrics after completion of colonoscopy include the generation of a high-quality endoscopy report and appropriate follow-up recommendations.

What should you expect post-procedure?

  • To receive a copy of a high-quality endoscopy report. It should document the indication for and extent of the exam, the quality of the prep, describe all abnormalities found including the number, size, location and appearance of any polyps and how they were removed; photo-documentation of important findings is preferred.
  • To receive instructions on the symptoms associated with serious post-colonoscopy complications and information about who to contact for questions/concerns.
  • To receive your pathology results and recommendations for follow-up.

Tips for post-procedure

  • Inform your family about your colonoscopy findings. If you have a CRC or an advanced polyp, it may have implications for the cancer risk in your relatives.

Contact Gastroenterology of the Rockies to Schedule an Appointment

If you’d like to learn more about prevention and screening for CRC or wish to schedule an appointment for a colonoscopy, please call Gastroenterology of the Rockies at 303-604-5000.