Subsequent surveillance intervals

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Definitions

Subsequent surveillance intervals herein refer to intervals for colonoscopies a patient would undergo following the baseline and first surveillance colonoscopies.

In this section

  • 1st colonoscopy refers to the baseline colonoscopy (initial, not surveillance)
  • 2nd colonoscopy refers to the first surveillance colonoscopy
  • 3rd colonoscopy refers to the second surveillance colonoscopy.

‘High-risk findings’ refers to advanced adenoma (size ≥10 mm, high-grade dysplasia [HGDHigh grade dysplasia], villosity) or ≥3 conventional adenomas.

Conventional adenomas include tubular, tubulovillous and villous adenomas.

Clinically significant serrated polyps include sessile serrated adenomas (SSAs), traditional serrated adenomas (TSAs), and large (≥10 mm) hyperplastic polyps (HPs).

Background

The 2011 Australian Clinical practice guidelines for surveillance colonoscopy[1] highlighted inconsistency in the literature guiding intervals for 2nd and subsequent surveillance colonoscopies. The importance of considering patient factors and colonoscopy history, most particularly whether the previous adenomas removed were low or high risk, was emphasised.

Generally, recommendations were tailored to risk determined by findings at the 1st and 2nd colonoscopy, with repeat of the high-risk surveillance interval for high-risk findings and in the setting of normal or low-risk findings, stopping surveillance or extending the surveillance interval as determined by the clinician on an individualised basis. No clear recommendations were given for second and subsequent colonoscopies for ≥5 adenomas, nor for serrated polyps.

In this section, intervals for conventional (tubular, tubulovillous and villous) adenomas and clinically significant serrated polyps (with or without synchronous conventional adenomas) are considered separately.

Understanding of the current literature base must consider dates of the colonoscopies performed (the quality of earlier procedures may falsely elevate incidence of metachronous neoplasia) and the lack of separate categorisation of serrated polyps.

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Overview of evidence (non-systematic literature review)

Four level III-2 studies with a high level of bias were identified.[2][3][4][5] Three studies were from Korea, with high proportions of males, and one was from the USAUnited States of America, with similar demographics to the Australian population. Although not directly generalisable, the results could be sensibly applied to the Australian population and healthcare system. Large numbers were included in most of the studies. Note is made of the wide range of results for risk of metachronous findings among studies in many settings mentioned below. The findings are summarised in Table 12.

In those who had low risk findings at 1st colonoscopy, the incidence of high risk findings at the 3rd colonoscopy ranged from 2.3–50.0%, depending on the findings of the 2nd colonoscopy. In those with low-risk 1st colonoscopy findings and a normal 2nd colonoscopy, it was 4.5–6.8%. The risk was only slightly higher (2.3–13.8%) in those with low risk findings on both 1st and 2nd colonoscopies. The greatest risk was in those with low risk 1st and high risk 2nd colonoscopy findings (18–50%).

In those who had high risk findings at 1st colonoscopy, the incidence of high risk findings at the 3rd colonoscopy had a similar range (9.6–50%) as when the 1st colonoscopy findings were low risk (2.3–50.0%). Within each risk category of 2nd colonoscopy findings, however, risk was elevated in high-risk 1st versus low-risk 1st colonoscopy findings. In those with high-risk 1st colonoscopy findings and a normal 2nd colonoscopy, it was 9.6–20.8%; in those with low-risk 2nd colonoscopy findings, it was 14–17.6%. The risk was greatest in those who had high risk findings on both 1st and 2nd procedures (15.8–50%).

No contemporary literature guides procedures following the 3rd colonoscopy. It is clear from the studies above that neoplasia decreases over time. Reasonably speaking, it is prudent to consider findings from the two most recent colonoscopies to recommend subsequent surveillance intervals thereby reducing complexity for clinicians. There is no literature base to inform recommendations on clinically significant serrated polyp surveillance. Therefore, the same principles as for conventional adenomas are suggested for subsequent surveillance interval recommendations.

IncidenceAn epidemiological term reporting number of new cases in a population within a specified period. of high risk findings at third colonoscopy relative to findings at first and second colonoscopies


Table 12. IncidenceAn epidemiological term reporting number of new cases in a population within a specified period. of high risk findings at the 3rd colonoscopy relative to findings at 1st and 2nd colonoscopies

High risk findings are classed as ≥3 or advanced adenoma (size ≥10mm, high-grade dysplasia or villosity)

Study details Morelli (2013)[2]

N=965

1985–2010

Chung (2013)[3]

N=131

1997–2011

Park (2015)[4]

N=4143

2001–2011

Suh (2014)[5]

N=852

2002–2009

Time to 2nd colonoscopy a29.1±17.7 to b38.3±21.22mc 17 (6–101) md 2.1y (1.7)e a19.2±8.8 to b37.1±16.9mc
Time to 3rd colonoscopy a32.6±15.1 to b46.2±18.4mc 24 (6–90) md 2.8y (2.5)e a23.0±9.9 to b33.0±15.0mc
1st colonoscopy

findings

2nd colonoscopy

findings

3rd colonoscopy incidence of high risk findings
Low risk Normal 6.6% 6.8% 4.5%
Low risk 13.8% 2.3% 10.6% 8.2%
High risk 18.0% 50% 24.3% 22.9%
High risk Normal 9.6% 17.7% 20.8%
Low risk 14.0% 17.5% 16.4% 17.6%
High risk 22.0% 50% 38.2% 15.8%
aHigh-risk group; blow-risk group; cmean ± standard deviation (SD) (m: months); dmedian (min–max) months; emean (inter-quartile range) years (y).
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Practice Points

Practice pointA recommendation on a subject that is outside the scope of the search strategy for the systematic review, based on expert opinion and formulated by a consensus process.Question mark transparent.png

The findings of the previous two colonoscopies predict high-risk findings on the subsequent colonoscopy and should be considered when recommending subsequent surveillance intervals.

Practice pointA recommendation on a subject that is outside the scope of the search strategy for the systematic review, based on expert opinion and formulated by a consensus process.Question mark transparent.png

For individuals who have undergone two or more colonoscopies, the surveillance interval for the next (3rd) colonoscopy should be based on the reports and histology from the two most recent procedures (1st and 2nd colonoscopies) as per Tables 14–16 (see Table 13 as a quick reference guide).

Table 13 ColonoscopyAn examination of the large bowel using a camera on a flexible tube, which is passed through the anus. findings and surveillance intervals: reference guide to Tables 14–16
1st colonoscopy findings 2nd colonoscopy findings 3rd colonoscopy

surveillance interval

Conventional adenomas only Normal colonoscopy or

conventional adenomas only

Table 14
Clinically significant serrated polyps

without synchronous

conventional adenomas

Table 15a
Clinically significant serrated polyps

with synchronous

conventional adenomas

Table 15b
Clinically significant serrated

polyps with or without

synchronous conventional

adenomas

Normal colonoscopy or

conventional adenomas only

Table 16
Clinically significant serrated polyps

without synchronous

conventional adenomas

Table 15a
Clinically significant serrated polyps

with synchronous

conventional adenomas

Table 15b
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Notes on the recommendations

Clinicians should make every effort to obtain procedure reports and histology from previous colonoscopies to inform whether a surveillance colonoscopy is indicated and the appropriate surveillance interval. If information is not available, first surveillance intervals should be used as per Table 3 (Conventional adenomas only) or Table 9 (Clinically significant serrated polyps ± conventional adenomas), although this will lengthen the surveillance interval for those with 2nd colonoscopy low-risk findings if 1st colonoscopy findings were high-risk.

Recommended surveillance intervals for 3rd colonoscopy


Table 14. Recommended surveillance intervals for 3rd colonoscopy – conventional adenomas only at 1st and 2nd colonoscopy Table 14 Conventional adenoma 3rdcol.PNG
Table 15. Recommended surveillance intervals for 3rd colonoscopy. a. (top) clinically significant serrated polyps only at 2nd colonoscopy. b. (bottom) clinically significant serrated polyps with synchronous conventional adenomas at 2nd colonoscopy.

Table 15ab 3rd col clinical serrated.PNG
Table 16. Recommended surveillance intervals for 3rd colonoscopy – clinically significant serrated polyps at 1st colonoscopy, no adenomas or conventional adenomas only at 2nd colonoscopy

Table 16 3rdcol no ad or conventional ad.PNG

Health system implications

Clinical practice

These guidelines are the first ever to separate conventional adenomas and clinically significant serrated polyps. There will be a learning curve for health care providers. The aim of the tables and colour-coding in this section is to facilitate transition from the old to new guidelines. An educational program and simple decision aids, such as wall charts and online decision tools, would help healthcare provider become familiar with the recommendations for surveillance intervals. These could be administered in conjunction with the relevant professional bodies and healthcare providers in both the public and private domains.

Resourcing

The resourcing implications of these guidelines are unclear and ideally would be assessed in a research forum.

Barriers to implementation

The main barrier for implementation of these recommendations will be dissemination across Australia and familiarisation for health care providers. This will be facilitated by a coordinated implementation and evaluation programme.

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References

  1. Cancer Council Australia ColonoscopyAn examination of the large bowel using a camera on a flexible tube, which is passed through the anus. Surveillance Working Party. Clinical Practice Guidelines for Surveillance Colonoscopy – in adenoma follow-up; following curative resection of colorectal cancer; and for cancer surveillance in inflammatory bowel disease. Sydney: Cancer Council Australia; 2011 Dec.
  2. 2.02.1 Morelli MS, Glowinski EA, Juluri R, Johnson CS, Imperiale TF. Yield of the second surveillance colonoscopy based on the results of the index and first surveillance colonoscopies. Endoscopy 2013 Oct;45(10):821-6 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/24019133.
  3. 3.03.1 Chung SH, Park SJ, Cheon JH, Park MS, Hong SPSerrated polyp, Kim TI, et al. Factors predictive of high-risk adenomas at the third colonoscopy after initial adenoma removal. J Korean Med Sci 2013 Sep;28(9):1345-50 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/24015041.
  4. 4.04.1 Park HW, Han S, Lee JY, Chang HS, Choe J, Choi Y, et al. Probability of high-risk colorectal neoplasm recurrence based on the results of two previous colonoscopies. Dig Dis Sci 2015 Jan;60(1):226-33 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/25150704.
  5. 5.05.1 Suh KH, Koo JS, Hyun JJ, Choi J, Han JS, Kim SY, et al. Risk of adenomas with high-risk characteristics based on two previous colonoscopy. J Gastroenterol Hepatol 2014 Dec;29(12):1985-90 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/24909388.

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