First surveillance intervals following removal of ≥5 conventional adenomas only

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Definition

Patients in whom ≥5 conventional (tubular, tubulovillous or villous) adenomas have been detected and removed are in a separate risk category from those with fewer adenomas. For surveillance intervals following removal of ≥5 conventional adenomas with synchronous clinically significant serrated polyps see First surveillance intervals following removal of serrated polyps (± conventional adenomas)

Background

In the 2011 Australian clinical practice guidelines for surveillance colonoscopy,[1] a surveillance interval of 1 year (5–9 adenomas) or within a year (≥10 adenomas) was recommended for individuals following the removal of ≥5 conventional adenomas at the index colonoscopy. Although the association of risk for metachronous advanced adenoma (MAAMetachronous advanced adenoma) and increasing numbers of adenomas detected and removed at index colonoscopy remains, in the era of high quality endoscopy, the magnitude of this risk may not be as great as previously.

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Evidence

What should be the surveillance interval following removal of ≥5 conventional adenomas only? [SAD5]

Systematic review evidence

The systematic review reported outcomes from three level III-2 studies.[2][3][4] One was at low[2] and two at moderate risk of bias.[3][4] Two studies were from Korea and the third from the USAUnited States of America, with a marked over-representation of males. Overall, although the evidence may not be directly generalisable, it could probably be sensibly applied to the Australian healthcare environment. In general, reported outcomes included metachronous adenomas (MAMetachronous adenoma), metachronous advanced adenomas (MAAMetachronous advanced adenoma), metachronous colorectal cancers (CRCColorectal cancer), metachronous advanced neoplasia (MANMetachronous advanced neoplasia) and metachronous neoplasia (MNMetachronous neoplasia) at follow-up of around 3 and 5 years. The three studies had different inclusions, thus limiting direct comparisons (see Table 6). There were no reports of long-term outcomes. In all studies, metachronous CRCColorectal cancer was uncommon with a risk of 0–0.8% in those with both 5–9 and ≥10 adenomas. The risk of MAAMetachronous advanced adenoma varied according to the number and other index adenoma features such as size and follow-up duration. The risk of MAAMetachronous advanced adenoma repotred in these studies was:

  • 5% in those with at least 5 adenomas all <10mm of any histology (n=169) after 3 years follow-up[2]
  • 9.1% for those with 5–9 non-advanced adenomas removed at index colonoscopy (n=99) after a mean follow-up of 4 years[3]
  • 11.9% for those with 3–10 adenomas (>60% advanced) removed at index colonoscopy (n=975) after a mean follow up of 4.0 years[4]
  • 16.3% in those with at least 5 adenomas with 1 ≥10mm (n=123) after 3 years follow-up[2]
  • 26.6% in those with >10 adenomas (>60% advanced) removed at index colonoscopy (n=214) after a mean follow-up of 4.3 years.[4]Back to top

Overview of additional evidence (non-systematic literature review)

Metachronous advanced neoplasia according to size of prior adenomas removed

One level III-2 study[5] investigated MANMetachronous advanced neoplasia after the removal of 3–9 non-advanced adenomas at index colonoscopy according to size (n=130). The incidence of MANMetachronous advanced neoplasia was 6.3% in the group with 3–9 adenomas sized 1–5mm (n=79) and 9.8% in the 3–9 adenomas sized 6–9mm (n=51) with a median follow-up of 32 months (interquartile range 13–48).

Table 6. Summary of studies with ≥5 adenomas – metachronous neoplasia

Author and design n Patient group at index colonoscopy Outcome and follow-up time
Advanced adenoma CRCColorectal cancer Advanced neoplasia
Park[3]

Retrospective multicentre

2007–2008

n=1394

99 5–9 NAANon-advanced adenoma 9.1%

4Y

0% AR 3Y AR 5Y
1.2%

(1.17–1.22)

6.4%

(6.34–6.46)

Park[4]

Retrospective multicentre

2009–2011

975 3–10 adenomas

(mean 4.5±1.9),

60% advanced adenomas

11.9%

4.0±1.2Y

0.1% AR 3Y AR 5Y
3.0%

(1.8–4.1)

16.2%

(12.3–20.1)

214 >10 adenomas

(mean 14.2±0.3),

68.2% advanced adenomas

26.6%

4.3±1.5Y

0 6.8%

(2.9–10.7)

28.7%

(20.8–36.5)

Vemulapalli[2]

Secondary analysis of a database

2002–2012

n=1859

143 5–10

All <10mm,

any histology

0.6% 5% (1068 days, SD 529)
103 5–10

at least one ≥10mm,

any histology

0.8% 16.3% (737 days, SD 553)
Sneh-Arbib[5]

2005–2013

Single centre

1–9mm with LGDLow grade dysplasia

n=1192

n Patient group at index colonoscopy Follow up years IncidenceAn epidemiological term reporting number of new cases in a population within a specified period./rate per 1000/per annum

HR (95% CI)

130 3–9 NAANon-advanced adenoma

All <10mm

282 <0.2% 7.7%/35.5/NA
79 3–9 NAANon-advanced adenoma

1–5mm

193 6.3%/25.9/1
51 3–9 NAANon-advanced adenoma

6–9mm

89 9.8%/56.2/2.4 (0.69–8.36)
Abbreviations: AR: absolute risk; CRCColorectal cancer: colorectal cancer; HR: hazard ratio; LGDLow grade dysplasia: low grade dysplasia; SD: standard deviation; NA: not applicable NAANon-advanced adenoma: non advanced adenoma; Y: years.
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Expert opinion and clinical practice guidelines from other countries

International recommendations demonstrate considerable variability (Table 7) and Table 4 Summary of international surveillance guidelines).

Table 7. International recommendations for multiple adenomas

International recommendation Adenoma description Recommended surveillance interval
American Gastroenterological Association[6] 3–10 tubular adenomas 3 years
>10 adenomas <3 years
British Society of Gastroenterology[7] ≥5 adenomas 1 year
Canadian Association of Gastroenterology[8] 3–10 tubular adenomas 3 years
>10 adenomas <3 years
European Society of Gastroenterology)[6] ≥3 adenomas 3 years
New Zealand[9] ≥5 adenomas 1 year
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Evidence summary and recommendations

Evidence summary Level References
In patients with 5–9 non-advanced adenomas at index colonoscopy, metachronous neoplasia was detected in almost 80% of patients at follow-up of 4.0±1.5 years. In the same group of patients, 100% had developed metachronous neoplasia at 6–7 years after index colonoscopy. III-2 [3]
In a group of 214 patients with >10 adenomas at index (14.2 ± 0.3 adenomas; 68.2% with advanced adenomas at index) neoplasia was detected in almost 90% of patients after a mean follow-up of 4.3 years. In the same group, metachronous neoplasia was detected in 100% of patients 8 years after index colonoscopy. III-2 [3]
In patients with 5–9 non-advanced adenomas at index (n=99), metachronous advanced adenoma was reported in 9.1% after a mean follow-up of 4 years. III-2 [3]
In patients with >10 adenomas at index (14.2±0.3 adenomas, 68.2% with advanced adenomas at index, n=214), metachronous advanced adenomas were reported in 26.6% after a mean follow-up of 4.3 years. III-2 [4]
The risk of metachronous advanced neoplasia was similar to that of advanced adenomas, and was 16.3% after 3 years of follow-up. III-2 [2]
Only one case of metachronous colorectal cancer was reported across two studies (n=551) in patients with no advanced adenomas at index. III-2 [3], [2]
Only one case of metachronous colorectal cancer was reported across two studies (n=1312) in patients with advanced adenomas at index. III-2 [3], [2]
Those with at least 5 adenomas with one ≥10mm had a detection rate of 2.4%, compared to no findings in those with 5 adenomas all ≤10mm, after 3 years follow-up. III-2 [2]
Those with at least 5 adenomas with 1 ≥10mm had a detection rate of MANMetachronous advanced neoplasia of 1.6%, compared to 0.6% in those with 5 adenomas all ≤10mm at index, after 3 years follow-up III-2 [2]
Those with at least 5 adenomas with 1 ≥10mm had a detection rate of 11.4% for tubular adenoma ≥10mm verse 3.7% for those with 5 adenomas all ≤10mm at index. III-2 [2]
Absolute riskThe risk a subject has for developing the tested disease over a stated time period. of metachronous advanced adenoma was reported in one study in patients with 5–9 non-advanced adenomas at index (n=99) at 3 years (AR=1.2%, CI=1.17–1.22) and 5 years (AR=6.4%, CI=6.34–6.46) follow-up. In another study it was reported that the risk of metachronous advanced adenomas in those patients with at least 5 adenomas all <10mm at index (OR=3.1, CI 1.2–8.2, p=0.021) with 1068±529 days follow-up. III-2 [3], [2]
At follow-up of 737±553 days after index colonoscopy, the risk of metachronous advanced neoplasia was significantly greater in patients with at least 5 adenomas with 1 ≥10mm, than in those with 1–2 adenomas all < 10mm (OR=10.8, CI=4.5-25.7, p<0.001). III-2 [2]
In a single study that reported outcomes in patients with >10 adenomas, the risk of metachronous neoplasia at follow-up of 4.3±1.5 years was significantly higher in those with >10 adenomas at index colonoscopy than in those with 3–10 adenomas at index colonoscopy (odds ratio 3.46; 95% CI 1.90–6.28). III-2 [4]
In a single study that separately reported the rate of metachronous advanced adenomas, the risk at follow-up of 4.3±1.5 years was higher in those with >10 adenomas at index colonoscopy than in those with 3–10 adenomas at index colonoscopy (odds ratio 2.25; 95% CI 1.49–3.38). III-2 [4]
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Evidence-based recommendationA recommendation formulated after a systematic review of the evidence, indicating supporting references.Question mark transparent.png Grade
≥5 conventional adenomas only

First surveillance intervals following complete removal of ≥5 conventional adenomas only, should be no longer than 3 years.

D
Consensus-based recommendationA recommendation formulated in the absence of quality evidence, after a systematic review of the evidence was conducted and failed to identify admissible evidence on the clinical question.Question mark transparent.png

≥5 conventional adenomas only

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 (HGDHigh grade dysplasia)
  • 1 year if any adenoma ≥10mm or with HGDHigh grade dysplasia and/or villosity

For those with ≥10 adenomas, the recommended surveillance interval is 1 year, regardless of size or histology.

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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

Surveillance intervals should be determined after the colon has been cleared of all significant neoplasia, once histology is known, and in the context of individualised assessment of benefit to the patient.

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

Consistently high-quality colonoscopy is imperative for optimal cost effectiveness and for implementation of uniform surveillance guidelines.

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

PolypA small growth protruding from a mucous membrane, such as the lining of the bowel./adenoma size as per the endoscopist documentation should be used for determining surveillance intervals. All endoscopists should ensure size measurements are accurate using a reference standard (eg an open biopsy forceps or snare).

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

Polyps removed at colonoscopy should be sent separately for histology to guide surveillance recommendations.

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

Clinicians should accurately record adenoma features relevant to surveillance intervals so that individualised surveillance recommendations can be made.

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

An underlying familial predisposition to colorectal cancer should be considered in all individuals with ≥10 polyps removed. Referral to a familial cancer clinic should be considered, along with appropriate psychological support.

Separate screening and surveillance recommendations apply to patients with diagnosed or likely familial syndromes (see Should family history affect surveillance intervals?).

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Notes on the recommendations

The systematic review supported surveillance within 3 years following removal of ≥5 conventional adenomas but did not offer guidance on intervals within this broad timeframe. General review of the literature offered further information to guide clinical practice and inform the current recommendations which are consistent with international guidelines.

The recommendations are based on the expectation that endoscopists in Australia are performing high quality colonoscopy with complete adenoma excision and are supported by accurate pathology reporting.

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Table 3. Summary of recommendations for first surveillance intervals following removal of conventional adenomas only Table 3 Removal conventional adenomas.PNGBack to top

Health system implications

Clinical practice

These surveillance guidelines will result in substantial change to which health care providers will need to adjust. The aim of Table 3 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 developed, promoted and distributed in conjunction with the relevant professional bodies and healthcare providers in the public and private domains.

Resourcing

The management of surveillance following removal of adenomas is critical in terms of health outcomes, demand for colonoscopy and cost. Recently, the Cancer Research Division, Cancer Council NSW used the Australian developed and validated model Policy1-Bowel[10] to compare the new and previous surveillance guidelines specifically related to the National Bowel Cancer Screening Program. Preliminary results demonstrate comparable health outcomes, reduced number of surveillance colonoscopies and similar program-related costs (see the preliminary results report on Modelled comparison of proposed surveillance recommendations for the NBCSP). There is likely to be an increased cost for pathologic assessment if a substantial proportion of health care providers currently do not submit all polyps removed for pathologic assessment or do not separate specimens.

Barriers to implementation

The main barrier for implementation of these recommendations will be dissemination across Australia and familiarisation for healthcare 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. 2.002.012.022.032.042.052.062.072.082.092.102.112.12 Vemulapalli KC, Rex DK. Risk of advanced lesions at first follow-up colonoscopy in high-risk groups as defined by the United Kingdom post-polypectomy surveillance guideline: data from a single U.S. center. Gastrointest Endosc 2014 Aug;80(2):299-306 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/24796960.
  3. 3.03.13.23.33.43.53.63.73.83.9 Park SK, Song YS, Jung YS, Kim WH, Soo Eun C, Ko BM, et al. Do surveillance intervals in patients with more than five adenomas at index colonoscopy be shorter than those in patients with three to four adenomas? A Korean Association for the Study of Intestinal Disease study. J Gastroenterol Hepatol 2017 May;32(5):1026-1031 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/27862272.
  4. 4.04.14.24.34.44.54.64.7 Park SK, Hwang SW, Kim KO, Cha JM, Boo SJ, Shin JE, et al. Risk of advanced colorectal neoplasm in patients with more than 10 adenomas on index colonoscopy: A Korean Association for the Study of Intestinal Diseases (KASID) study. J Gastroenterol Hepatol 2017 Apr;32(4):803-808 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/27785837.
  5. 5.05.1 Sneh Arbib O, Zemser V, Leibovici Weissman Y, Gingold-Belfer R, Vilkin A, Eizenstein S, et al. Risk of advanced lesions at the first follow-up colonoscopy after polypectomy of diminutive versus small adenomatous polyps of low-grade dysplasia. Gastrointest Endosc 2017 Mar 8 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/28284884.
  6. 6.06.1 Lieberman DA, Rex DK, Winawer SJ, Giardiello FM, Johnson DA, Levin TR. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2012 Sep;143(3):844-857 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/22763141.
  7. Cairns SR, Scholefield JH, Steele RJ, Dunlop MG, Thomas HJ, Evans GD, et al. Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002). Gut 2010 May;59(5):666-89 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/20427401.
  8. Leddin D, Enns R, Hilsden R, Fallone CAConventional adenoma, Rabeneck L, Sadowski DC, et al. Colorectal cancer surveillance after index colonoscopy: guidance from the Canadian Association of Gastroenterology. Can J Gastroenterol 2013 Apr;27(4):224-8 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/23616961.
  9. New Zealand Guidelines Group. Colorectal cancer: Management of Early Colorectal Cancer. Wellington: Ministry of Health; 2011.
  10. Lew JB, St John DJB, Xu XM, Greuter MJE, Caruana M, Cenin DR, et al. Long-term evaluation of benefits, harms, and cost-effectiveness of the National Bowel Cancer Screening Program in Australia: a modelling study. Lancet Public Health 2017 Jul;2(7):e331-e340 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/29253458.

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Appendices

Jutta's magnifying glass icon.pngPICO question SAD 5 View Evidence statement form SAD5Evidence statement form SAD5 View Systematic review report SAD5Systematic review report SAD5
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