5 Risk Factors for Missed Colon Cancer or Polyps During Your Colonoscopy
The first and possibly the most important is an adequate bowel preparation
The ability to see pre-cancer polyps and colon tumors is dependent on you having colon clear of residual stool. This is dependent on you completing the bowel preparation as prescribed as well as drinking lots of supplemental fluid during the prep. All preps require you to fast from solids for a full day before your exam and only drink clear fluids. If you have had a prior poor prep or have tendency to be constipated, take medications or have conditions that slow the movement of your bowels then you may be asked to stop eating solids two days before your exam.
You will be asked to take one of several bowel preparations as directed by your provider. It has been proven that split dosing (dividing the preparation medications into two separate timed doses, typically the evening before very early on the day of the exam) achieves the highest success rate in adequate clearing of the colon. It cannot be over emphasized that no matter what prep you use; all of them are work the best when you drink lots of clear liquids.
Despite being given very detailed bowel preparation instructions some individuals fail to follow these instructions especially drinking plenty of fluids. Some just fail to drink adequate fluids during the prep or fail to avoid eating the day before or start too late to have adequate time to clear out all the stool and fluid. The patients in whom inadequate bowel prep is noted must be rescheduled for a repeat exam. You don't want to go through the bowel preparation half-heartedly only to have to be canceled or have an incomplete or inadequate colonoscopy that requires a repeat exam.
Non-gastroenterologist preforming exam increases risk of missed lesion
Multiple studies have confirmed that the risk of missed polyps and colon cancers is much higher when a physician other than a gastroenterologist performs the colonoscopy exam. The risk of missed polyps has been reported as high as 50% when colonoscopy is performed by a non-gastroenterologist. If possible you should insist that either a gastroenterologist performs your colonoscopy or a colorectal surgeon who routinely performs many exams a year. Most gastroenterologists perform over a 1000 colonoscopies a year.
Incomplete exam during your first colonoscopy risks missed lesions
Failure to reach the end of the colon is known risk for missed colon polyps and colon cancer. Inexperienced endoscopists and non-gastroenterologists may fail to reach the cecum but not be aware. Photo documentation of the anatomical landmarks of the cecum are increasingly used by endoscopists to document the extent of the exam was complete. If it is not clear from your report that exam was complete you should as
Women and older age
Several studies have shown that the female gender and older age are independent risk factors for missed polyps and interval colon cancers. If you are a woman or an older individual you should be aware of these risks and not be dissuaded from insisting that you had adequate bowel prep, complete and careful withdrawal examination. Some women have more difficult examinations technically than men and older patients may also have significant diverticular disease making the examination more difficult so an experienced endoscopist is important. Also older patients commonly have multiple other medical problems that may influence the endoscopist to try to complete the exam quickly to avoid intra-procedure complications including sedation issues.
Inexperienced endoscopists or those with poor technique or too rapid exam
More experienced endoscopists miss less lesions than trainees and less experienced endoscopists even when time of withdrawal is equal. The accepted standard for withdrawal time is now six minutes or more. Almost all exams report withdrawal time and many endoscopists have known withdrawal time averages correlated with their polyp detection rate. Subpar withdrawal times and polyp detection rates would be an indicator that an endoscopist's technique is below that generally accepted within peers. Poor endoscopy technique is related to training of the endoscopist as well as number of procedures performed in the past. As the number of procedures increase the skill of the endoscopist almost always improves