CPG: Surveillance Colonoscopy Flashcards
Describe the 2019 CPG practice points regarding bowel preparation in Surveillance Colonoscopy
High-quality bowel preparation is a crucial pre-requisite for successful colonoscopy. Optimal preparation is achieved with split-dose or same-day preparation timing.
PEG-based bowel preparations are safer for those with co-morbidities and the elderly.
A low-residue diet can be used on the days prior to colonoscopy with appropriate preparation timing.
Preparation quality should be documented on the colonoscopy report using a validated preparation scale.
Where the preparation is inadequate, repeat colonoscopy should normally be offered within 12 months.
Successful bowel preparation should be achieved in ≥90% of all colonoscopies.
Describe the practice points regarding technique in surveillance colonoscopy as per the 2019 CPG.
Fundamental colonoscopic inspection technique should ensure systematic exposure of the proximal sides of folds and flexures, intensive intraprocedural cleansing and adequate distension of the colon.
Water exchange should be considered to improve adenoma detection through an effect on mucosal cleansing and higher rates of adequate bowel preparation.
A second examination of the proximal colon in either the forward view or in retroflexion is recommended to improve lesion detection, particularly in patients with an expected higher prevalence of neoplasia.
Sessile polyps under 10mm in size should be removed using cold snare polypectomy. This is preferred over hot snare, which is unnecessary in most situations. Hot biopsy forceps should not be used because they are associated with unacceptably high rates of incomplete resection and deep mural injury.
Describe the 2019 CPG on Surveillance Colonoscopy with regard to adjunct technologies and technological advances.
High-definition colonoscopes should be used routinely, as the mainstay of colonoscopy is a careful white-light examination of the well prepared colon.
Electronic chromoendoscopy should be used for lesion characterisation, but has limited value in lesion detection.
Chromoendoscopy should be considered for patients undergoing surveillance for inflammatory bowel disease, although a recent study has shown equivalence with high resolution white-light endoscopy.
CO2 insufflation should be used routinely to improve patient tolerability of colonoscopy.
What are the quality indicators described by the 2019 CPG regarding surveillance colonoscopy?
Less than 10% of patients should require a repeat procedure due to poor bowel preparation, this should be offered within 12 months.
Unadjusted rates for caecal intubation should be ≥90%.
Photo-documentation, that terminal ileum or the base of the caecum (appendix orifice and ileocaecal valve) has been reached, should be performed to confirm completeness of the examination.
Withdrawal times of >6 minutes for examinations without polypectomy are a surrogate marker for adenoma detection rates, but cannot be relied on as an independent quality indicator.
Individual proceduralists should routinely document and maintain their adenoma detection rate at >25% in patients over the age of 50-years and without a diagnosis of inflammatory bowel disease.
Serrated polyp detection rates are likely to be an equally valid marker of quality as adenoma detection rate, and increasing evidence suggests that maintaining a rate of >10% in patients over age 50 years without a diagnosis of inflammatory bowel disease may prove to be an additional, useful quality indicator in the future.
Perforation rates post colonoscopy should be <1/1000. This is more relevant for population programs and large endoscopy units rather than individual colonoscopists.
Comprehensive computer-generated colonoscopy reports with embedded photo-documentation should be generated at the time of the procedure, and provided to patients and relevant clinicians.
What are the 2019 CPG practice points regarding CT colonography?
It is safe to perform same-day CT colonography following incomplete colonoscopy, including in patients who have had a biopsy or simple polypectomy. However, CT colonography should be delayed in patients with complex endoscopic intervention and in patients at high risk of perforation such as active colitis or high-grade stricture.
CT colonography should only be interpreted by radiologists who have undergone specialist training and are accredited by RANZCR.
Patients with a CT colonography detected polyp over 10mm should be referred for polypectomy. Patients with polyps 6–9mm can be offered either polypectomy or repeat colonic examination at 3 years.
What are the 2019 CPG recommendations for surveillance of “low risk conventional adenomas”?
Any caveats?
Low risk = 1-2 small (<10mm) adenomas w/o HGD
- First surveillance interval of 10 years is appropriate for most individuals
- Return to the NBCSP with a FOBT after 4 years, is an appropriate option and should be discussed with the patient.
- A shorter surveillance interval of 5 years could be considered for men who fit the criteria for the metabolic syndrome, because they may have increased risk of metachronous advanced neoplasia following removal of low- risk adenomas.
What are the 2019 CPG recommendations for surveillance of “high risk conventional adenomas”?
What is different about NZ’s guidelines regarding high risk adenomas?
High risk adenomas = one or more of the following features:
- Size >10mm
- High grade dysplasia
- Villous architecture
- 3-4 adenomas
5-year high risk adenomas:
- 1-2 adenomas with HGD or villous architecture
- 3-4 adenomas w/o HGD all of which are <10mm
3-year high risk adenomas
- 1-2 adenomas with HGD or villous architecture ≥10mm
- 3-4 tubular adenomas where the size of one or more is ≥10mm
- 3-4 tubulovillous and/or villous (+/- HGD) all <10mm
NZ considers HGD or villousity to be a high risk feature independent of number or size of adenoma. If presents, 3 year surveillance is recommended (2020 guidelines)
What are the “high risk” features of a conventional adenoma according to NZ and Aus criteria?
- Size (>10mm)
- Number (>4)
- Villousity (presence)
- High grade dysplasia (presence)
Generally speaking, if present, these factors reduce the surveillance interval to the proximate tier.
In NZ, the presence of any one of these in adenomata reduces surveillance from 5 to 3 years. In Australia HGD or villousity are considered to confer less risk unless 3 or more polyps display HGD or villousity.
What are the 2019 CPG recommendations for surveillance of ≥5 adenomas?
Any difference with NZ guidelines?
First surveillance intervals should be within 3 years and stratified based on the number, size and histology following complete removal of ≥5 adenomas only.
For those with 5–9 adenomas, recommended surveillance intervals are:
• 3 years if all tubular adenomas <10mm without high grade dysplasia (HGD)
• 1 year if any adenoma ≥10mm or with HGD and/or villosity.
For those with ≥10 adenomas, the recommended surveillance interval is 1 year, regardless of size or histology.
In NZ, the only rationale for 1 year surveillance of adenomas is >10 polyps. Adenomas with HGD or villous features still get surveillance at 3 years even if over 10mm.
What is the evidence-based statement regarding SSP surveillance?
In the context of only serrated lesions being found, what are the follow up guidelines?
First surveillance intervals should be no greater than 5 years and should be based on features of synchronous conventional adenomas (if present) following complete removal.
Clinically significant serrated polyps only and no adenomata
5 years for:
- 1–2 sessile serrated adenomas all <10mm without dysplasia.
3 years for:
- 3–4 sessile serrated adenomas, all <10mm without dysplasia
- 1–2 sessile serrated adenomas ≥10mm or with dysplasia, or hyperplastic polyp ≥10mm
- 1–2 traditional serrated adenomas, any size.
1 year for:
- ≥5 sessile serrated adenomas <10mm without dysplasia
- 3–4 sessile serrated adenomas, one or more ≥10mm or with dysplasia
- 3–4 traditional serrated adenomas, any size.
i.e TSA, size, and number confer risk enough to shorten surveillance interval.
What do the 2019 CPG consider “clinically significant” serrated polyps?
Which hyper plastic polyps do not require surveillance?
- sessile serrated adenomas
- traditional serrated adenomas
- hyperplastic polyps ≥10mm
Small, particularly distal, true hyperplastic polyps do not require surveillance.
What are the 2019 CPGs for surveillance of large sessile or laterally spreading lesions?
Who should perform EMR?
First surveillance interval should be approximately 12 months in individuals who have undergone en-bloc excision of large sessile and laterally spreading lesions.
First surveillance interval should be approximately 6 months in individuals who have undergone piecemeal excision of large sessile and laterally spreading lesions.
Consideration should be given to referring large sessile and laterally spreading lesions to experienced clinicians trained in and regularly undertaking high quality EMR to reduce the risk of recurrence.
Generally speaking, what is the effect on subsequent colonoscopies when polyps are detected?
i.e. summarise the 2019 CPGs on risk stratification and interval between surveillance
Essentially, the higher risk your index colonoscopy, the shorter your interval to the next surveillance colonoscopy. Such that, if you were deemed high risk on index colonoscopy (e.g. 7 polyps with HGD) then even if you have “lower risk” findings at the time of your second colonoscopy (e.g. 3 polyps less than 10mm with HGD) then the interval will reduce to the shorter (e.g 1 year not 3).
Describe the 2019 CPG for Polyp Surveillance in the elderly.
Surveillance colonoscopy in those ≥75 years should be considered based on age, co-morbidity and the preferences of the patient. The reproducible and validated Charlson score is useful to assess life expectancy and could be implemented to assist decision-making.
Summarise the Charlson Score in the context of colonoscopy utility as per the 2019 CPG
A Charlson Score of >4 suggests colonoscopy is not recommended.
Age 75-79 receives a score of 3. Mild systemic disease of one organ system receives a score of 1 (e.g. diabetes w/o end organ damage, previous MI, COPD). Severe systemic disease receives a score of ≥2 (e.g.complicated diabetes 2, severe liver disease 3, metastatic cancer 6).
What do the 2019 CPG on Colonoscopy Surveillance consider to be a “low risk malignant polyp”?
Low-risk malignant polyps have all of the following features: superficial submucosal invasion (<1000 microns), moderate or well differentiated histology, no lymphovascular invasion, clear margins and no other risk features.
In these cases, where the endoscopist is certain that the lesion has been completely removed, then the neoplasm should be considered cured by endoscopic polypectomy.
Polyps that do not satisfy low risk criteria or have other histological risk features (often not routinely reported) including: malignant invasion depth >2mm, invasion width >3mm, tumour budding and cribriform architecture, should be considered at risk of harbouring residual bowel wall cancer or lymph node metastases.
What are the surveillance recommendations for a malignant polyp?
Surveillance recommendations for a T1 adenocarcinoma. First surveillance in one year with subsequent surveillance determined by findings.
Describe the CPG evidence based recommendations regarding follow up colonoscopy in a treated obstructing colorectal lesion
Colonoscopy should be performed 3–6 months after resection for patients with obstructive colorectal cancer in whom a complete perioperative colonoscopy could not be performed and in whom there is residual colon proximal to the location of the pre-operatively obstructing cancer.
If the index colorectal cancer (CRC) obstructs the lumen and prevents passage of a colonoscope, consideration should be given to specific pre-operative assessment of the proximal colon by alternative means. CT colonography (CTC) can be considered. However, its role in this clinical scenario requires further analysis. It is safe to perform same-day CTC following an incomplete colonoscopy, including in patients who have had a biopsy or simple polypectomy. CTC should be delayed in patients with complex endoscopic intervention and in patients at high risk of perforation, such as those with active colitis or high-grade stricture.
Describe or draw the table detailing follow up of conventional adenoma detected on colonoscopy with regard to number, size, dysplasia, and villosity.
