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First categorize polyps based on pathology into neoplastic vs non-neoplastic polyps (Gupta 2020).
Non-neoplastic polyps include:
Neoplastic polyps include: (categorized by histology)
Sessile serrated polyps (SSP) look similar to hyperplastic polyps on endoscopic evaluation. They are flat or minimally raised polyps with a subtle appearance. They are more frequently located in the proximal colon and microscopically they share many characteristics with hyperplastic polyps but they have more disorganization and serrated edges. SSPs are important to identify because they are easily missed and the presence of sessile serrated polyps increases the odds of developing colon cancer threefold compared to someone with a normal colonoscopy (Erichsen 2016,Gupta 2020). Part of the reason SSPs require closer follow up is because they are more difficult to identify on colonoscopy.
Size and Location
In addition to the type of polyp, the size of the polyp helps determine the surveillance interval. Polyps range from 2mm (~smallest you can see) to multiple centimeters in size. An important delineation of polyp size is <10mm in size vs. ≥10mm in size. Polyps ≥10mm in size are considered high risk and require closer follow up (Gupta 2020). The location of the polyp doesn’t guide follow up intervals, but it can provide insight into whether there could be a polyposis syndrome. Furthermore large right-sided hyperplastic polyps on pathology report raise Dr. Maranki’s suspicion for the possibility of a sessile serrated polyp as these two polyps can look similar on microscopic evaluation.
Advanced adenoma is an adenoma with any of the following
A high-quality colonoscopy is defined by multiple variables (Keswani 2021). First, the bowel preparation needs to be adequate. Differences in prep depend on local availability, insurance coverage, and comorbidities. Patients should follow a low residue diet 1-2 days prior to the colonoscopy (low fiber, easily digestible foods). Foods to avoid include nuts, dried fruit, berries, seeds, and many vegetables (Mentioned UMH Colonoscopy Guide). Low volume preparation solutions and polyethylene glycol + Gatorade have been associated with improved tolerability (Gu 2019). Below are examples of common preparations:
For patients with risk factors for inadequate prep such as chronic constipation, diabetes or chronic opiate use, Dr. Maranki recommends a clear liquid diet for multiple days prior to colonoscopy.
In addition to the bowel prep, look for scope advancement to the cecum or terminal ileum in a patient without prior surgery. For the adequacy of bowel prep, at a minimum look for “adequate” bowel prep. This implies the bowel prep was adequate to detect polyps >5mm. There are a variety of scales used to indicate adequate bowel prep such as the Boston Bowel Prep Scale (Lai, 2009). Bowel prep described as “good, excellent or adequate” above the threshold needed “fair, suboptimal or poor” are red flags which indicate the prep was not adequate to detect polyps. In average-risk patients with good-quality prep, adenomas are identified in at least 30% of men and at least 20% of women during first screening colonoscopy (Rex 2015, Heitman 2009). A minimum of 6 minutes should be spent on withdrawal of the endoscope, as most of the the evaluation for polyps is completed during withdrawal (Rex 2015).
Follow up guidelines assume adequate prep and apply to patients at average risk for colorectal cancer (Gupta 2020). Patients are considered high risk if they have a family history of colon cancer, advanced polyps in a first degree relative, or a personal history of inflammatory bowel disease.
Based on the size and type of polyps identified, repeat surveillance is recommended ranging from 1 to 10 years (Gupta 2020). Dr. Maranki recommends a number instead of a range when planning a follow up interval for patients to generate improved recall. Factors that push Dr. Maranki to choose the shorter side of the range include family history, size of polyp, and number of polyps.
Recommended follow up should be adjusted based on findings from the most recent colonoscopy. A decreased maximum interval of 5 years should only be considered for patients at high risk for CRC due to family history. Other methods of CRC screening such as FIT or FIT DNA testing are not recommended for surveillance following polyp detection.
Figure from the US Multi-Society Task Force on Colorectal Cancer regarding recommendations for follow up after colonoscopy and polypectomy in average risk adults: (Gupta, 2020)
A colonoscopy is generally a safe and well tolerated procedure (Rex 2015). Risks increase with polypectomy but complications remain rare. Abnormal bleeding occurs in 1-2% post polypectomy, and the incidence can increase to 5-10% following a large polyp resection such as endoscopic mucosal or submucosal for polyps >2cm in size (ASGE 2011). Bleeding can be immediate or delayed, and delayed bleeding (up to 3 weeks after colonoscopy) is more common if electrocautery is used with the snare for polypectomy. Small amounts of bleeding including streaks of blood in stool up to tablespoons of blood can be normal following polypectomy, but it should improve with each bowel movement.
Perforation is a rare but serious complication, occurring in <<1% patients following a typical polypectomy but up to 5% in the setting of mucosal or submucosal resection (Lohsiriwat, 2010). Post polypectomy syndrome is another potential complication that can present as focal peritonitis symptoms including fever, leukocytosis, or abdominal pain without evidence of perforation. It is usually managed outpatient with supportive care bowel rest but occasionally requires hospitalization (Reumkens 2016).
Listeners will review important characteristics of colon polyps and develop an approach to the updated colon polyp follow up.
After listening to this episode listeners will…
Dr. Maranki receives a consulting fee from Boston Scientific. The Curbsiders report no relevant financial disclosures.
Gibson EG, Maranki J, Okamoto EE, Grant K, Williams PN, Watto MF. “#353 Colon Polyps: Polyps, Polepectomy & Surveillance with Dr. Jennifer Maranki”. The Curbsiders Internal Medicine Podcast. http://thecurbsiders.com/episode-list September 12, 2022
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