ORIGINAL ARTICLE

Comparison of High Definition with Standard White LightEndoscopy for Detection of Dysplastic Lesions DuringSurveillance Colonoscopy in Patients with ColonicInflammatory Bowel DiseaseVenkataraman Subramanian, MD, DM, MRCP(UK),*,† Vidyasagar Ramappa, MD, MRCP(UK),†

Emmanouil Telakis, MD,† Jayan Mannath, MD, MRCP(UK),† Aida U. Jawhari, PhD, FRCP,†

Christopher J. Hawkey, DM, FRCP,† and Krish Ragunath, MPhil, FRCP†

Background: Dysplasia in colonic inflammatory bowel disease (IBD) is often multifocal and flat. High-definition (HD) colonoscopy improves

adenoma detection rates by improving the ability to detect subtle mucosal changes. The utility of HD colonoscopy in dysplasia detection in

patients with IBD has not been reported so far. We aimed to compare the yield of dysplastic lesions detected by standard definition (SD) white

light endoscopy with HD endoscopy.

Methods: A retrospective cohort study of patients with long-standing (>7 years) colonic IBD undergoing surveillance colonoscopy at Notting-

ham University Hospital was studied between September 2008 and February 2010. Details of diagnosis, duration of disease, and outcomes of the

colonoscopy were collected from the endoscopy database, electronic patient records, and patient notes.

Results: There were 160 colonoscopies (101 ulcerative colitis [UC] and 59 Crohn’s disease [CD]) in the SD group and 209 colonoscopies (147

UC and 62 CD) in the HD group. The groups were well matched for all demographic variables. Thirty-two dysplastic lesions (27 on targeted

biopsy) were detected in 24 patients in the HD group and 11 dysplastic lesions (six on targeted biopsy) were detected in eight patients the

SD group. The adjusted prevalence ratio of detecting any dysplastic lesion and dysplastic lesion on targeted biopsy was 2.21 (95% confidence

interval [CI] 1.09–4.45) and 2.99 (95% CI 1.16–7.79), respectively, for HD colonoscopy.

Conclusions: HD colonoscopy improves targeted detection of dysplastic lesions during surveillance colonoscopy of patients with colonic IBD

in routine clinical practice. Randomized controlled studies are required to confirm these findings.

(Inflamm Bowel Dis 2012;000:000–000)

Key Words: surveillance, UC, Crohn’s colitis, dysplasia, high definition

P atients with ulcerative colitis (UC) have an increased

risk for colorectal cancer (CRC) compared to the gen-

eral population.1 Cancer in UC occurs at a younger age

and increases with time, approaching 18% after 30 years of

disease.1 This increased risk has prompted both the North

American and UK gastroenterology societies to recommend

cancer prevention strategies.2,3 Random sampling through-

out the colon has been the mainstay of conventional sur-

veillance practice. Surveillance colonoscopy requires multi-

ple biopsies to be taken and processed, which is tedious,

expensive, and time-consuming. It has been estimated that

at least 33 biopsies are needed to achieve 90% confidence

to detect dysplasia if it is present.4 Surveillance colono-

scopy practices are not uniform and less than 10 biopsies

were noted to be taken based on gastroenterologists self-

reported practices for colonoscopic surveillance for UC.5

The focus of dysplasia in UC is flat and multifocal

and can be easily overlooked with conventional white light

endoscopy.6 There is growing evidence that the yield of

surveillance can be improved by addition of newer endo-

scopic methods that enhance the detection of subtle muco-

sal abnormalities like chromoendoscopy (CE) and auto-

fluorescence with narrow-band imaging (NBI).7 CE refers

to the topical application of dyes or pigments to improve

Received for publication April 8, 2012; Accepted April 9, 2012.

From the *Department of Gastroenterology and Leeds Institute of Molecular

Medicine, St James University Hospital, Leeds, UK, †Nottingham Digestive

Diseases Centre, Nottingham University Hospital, UK.

Venkataraman Subramanian was the recipient of an NIHR clinical

lecturership from the National Institute of Health Research (UK). Krish

Ragunath has received educational/grant support from Olympus (Keymed,

UK).

Reprints: Dr. Venkataraman Subramanian, Department of Gastroenterology, St

James University Hospital, Leeds LS9 7TF, UK (e-mail: venkat.subramanian@

leedsth.nhs.uk).

Copyright VC 2012 Crohn’s & Colitis Foundation of America, Inc.

DOI 10.1002/ibd.23002

Published online in Wiley Online Library (wileyonlinelibrary.

com).

Inflamm Bowel Dis 1

detection and delineation of surface abnormalities and is an

inexpensive adjunct to conventional endoscopy. It has been

shown to be useful in the detection of flat adenomas in the

sporadic setting as well as in patients with familial polypo-

sis syndromes.8,9 There is increasing evidence that most

dysplasias in UC are associated with visible mucosal

abnormalities.10,11 This has in turn led to increasing use of

endoscopic resection techniques to treat areas of raised,

visible dysplasia in patients with UC, without the need for

colectomy.12 There is therefore a need to improve detection

techniques during surveillance endoscopy. A recent meta-

analysis suggested that CE is superior to standard definition

(SD) white light colonoscopy for detection of dysplasia but

this technique has not been widely accepted in routine clin-

ical practice.13

High definition (HD) colonoscopy has also shown

promise in improving the detection of colorectal polyps

and adenomas.14 More recently HD with additional CE was

only shown to only marginally improve the adenoma detec-

tion rate compared to HD alone.15 With an increase in the

number of endoscopy units switching to HD endoscopes,

we sought to determine if the use of HD colonoscopes was

associated with increased detection of dysplastic lesions

both overall and targeted during surveillance colonoscopies

for patients with colonic inflammatory bowel disease (IBD)

in our institution.

MATERIALS AND METHODS

Data CollectionThe computerized clinical and endoscopic database of

the Nottingham University Hospitals served as the data source

for this retrospective cohort study. We reviewed the computer-

ized charts of consecutive patients with IBD undergoing colo-

noscopies between September 2008 and February 2010 at Not-

tingham University Hospital. Patient information was

collected regarding age, sex, diagnosis, extent of disease, use

of 5-aminosalicylates, use of immunomodulator medications

or biological drugs, number of biopsies taken during the colo-

noscopy, whether lesions were noted and if a dysplastic lesion

was confirmed on histopathology, and if colonoscopy was

done by a consultant, nurse endoscopist, or trainee and if an

HD scope and monitor was used. During colonoscopy infor-

mation was recorded about the location and size of any visible

abnormalities.

Only colonoscopies performed with CFH260DL (Olym-

pus, Keymed, UK) colonoscopies using an Olympus Excera

processor and an HD 1080i capable monitor (Olympus

OEV191H) were classed as high definition. All the other pro-

cedures were classed as standard definition and included

Olympus series scopes CF230L, CF240L, CF240 AL, CF240

DL, CF 260DL, and CF Q260DL. Bowel preparation was with

either two sachets of Picolax or four sachets of Kleen Prep

with two tablets of Senna.

During the time period of this study the British Society

of Gastroenterology recommended taking four quadrant biop-

sies every 10 cm2 and this was the protocol adopted by the

endoscopy unit at Nottingham. However, this was not

enforced and individual clinicians were allowed to practice

according to their clinical judgment. All endoscopists, how-

ever, took targeted biopsies of any lesions detected. Biopsy

materials were processed according to standard procedures

and read by an expert gastrointestinal pathologist. When there

was dysplasia or cancer the consensus opinion of two patholo-

gists was reported. Histology was classified according to the

Vienna criteria of gastrointestinal epithelial neoplasia ranging

from no intraepithelial neoplasia to invasive neoplasia.16

Patient Inclusion and Exclusion CriteriaPatients over the age of 18 years with a confirmed diag-

nosis of UC (at least left-sided) or Crohn’s colitis involving a

least one-third of the colon and disease duration of at least 7

years undergoing colonoscopy were included in the study.

Patients undergoing a planned therapeutic procedure or

referred from another center with a diagnosis of dysplasia/

cancer were excluded.

Statistical AnalysisNumeric variables are summarized with the sample

mean and standard deviation and categorical variables with

the number and percentage. The primary endpoints of interest

were the number of patients with any dysplastic lesion

detected and the number of patients with endoscopcially visi-

ble dysplastic lesions. The secondary endpoints were the num-

ber of high-grade dysplasia’s and cancers detected and the

number of patients with endoscopically visible flat dysplastic

lesions. The risk of association between the outcome variables

of interest and type of endoscopy (HD or SD) was estimated

using Poisson regression with robust standard errors rather

than the more commonly used logistic regression.17,18 The

choice of the Poisson model, which provides a prevalence

ratio (PR), was based on the fact that the outcomes were rela-

tively common. The Poisson model provides a more conserva-

tive estimate of the relative risk that is closer to its sample

value than when logistic regression is used in cross-sectional

studies. Potential confounders that were included in multiple

regression models were age, gender, duration of disease,

5-aminosalicylate use, extent of disease, exposure to immuno-

modulators or biologics, experience of colonoscopist, ade-

quacy of bowel preparation, and total number of biopsies

taken. A two-sided significance level was set at P < 0.05. The

statistical software SPSS v. 17 (Chicago, IL) and Stata v. 10

(College Station, TX) were used in all analyses.

RESULTSThe database search revealed 870 lower gastrointesti-

nal (GI) endoscopies that were done on 792 patients, of

which 98 were wrongly coded in the endoscopy database

Inflamm Bowel DisSubramanian et al

2

and did not have IBD, 188 were flexible sigmoidoscopes

not intended for surveillance, 106 did not meet the inclu-

sion criteria as they had less than 7 years of disease, 94

had limited colitis, two were referred with a diagnosis of

cancer high grade dysplasia (HGD) for further manage-

ment, and three were having planned therapeutic colonos-

copies for endoscopic resection of previously detected dys-

plastic lesions. In all, 369 colonoscopies done on 353

patients were included in the final analysis. Table 1 is a

summary of the patient demographics, disease characteris-

tics, and endoscopist characteristics for the 160 SD colo-

noscopies and 209 HD colonoscopies. The groups were

well matched for age, gender, diagnosis, extent of disease,

disease duration, and mean number of biopsies taken per

patient. There were significantly more patients on 5-amino-

salicylates in the HD group (89%) than the SD group

(81%). Significantly more colonoscopies in the HD

group (37%) were done by trainees compared to the SD

group (10%).

Eleven dysplastic lesions were detected in 8/160

colonoscopies in the SD group. Thirty-two dysplastic

lesions were detected in 24/209 colonoscopies in the HD

group. There were two patients with cancer and one patient

with HGD (noted on random biopsies) in the SD group.

There were five patients with cancer and two with HGD

(all picked up on targeted biopsies) in the HD group. Table

2 provides details of the number and characteristics of

lesions detected by the two modalities. Table 3 provides

the adjusted and unadjusted PR of picking up any dysplas-

tic lesion, HGD, or cancer, endoscopically visible dysplas-

tic lesions, and endoscopically visible flat dysplastic lesions

with HD colonoscopy compared to SD colonoscopy. Sig-

nificantly more dysplastic lesions were detected by HD

colonoscopy and there was significantly increased detection

of dysplastic lesions noted on targeted biopsies with HD

colonoscopy.

DISCUSSIONOur study shows that the use of HD colonoscopies is

associated with higher dysplasia detection rate in compari-

son to SD colonoscopy. This was most apparent for dys-

plastic lesions detected by targeted biopsies, especially on

the right side of the colon where 18 lesions (16 on targeted

biopsy) were detected by HD colonoscopy while four

lesions (three on targeted biopsy) were detected by SD

colonoscopy. SD colonoscopy has been felt to be poor at

picking up right-sided lesions at colonoscopy, which are

more likely to be flat or sessile.19 The clinical implications

of picking up a larger number of right-sided lesions needs

to be evaluated in the long term, especially in relation to

reduction in cancer-related mortality. Several studies have

now confirmed that local endoscopic resection with close

follow-up is a safe alternative to colectomy in selected

patients with dysplastic lesions detected on surveillance

colonoscopy.20,21 The increased rates of targeted yield of

dysplastic lesions by HD colonoscopy suggest that it could

help detect dysplastic lesions for endoscopic resection and

reduce the need for colectomy.

CE and electronic CE (NBI, Fujinon intelligent

chromo endoscopy and Pentax i-scan) have all been advo-

cated to improve endoscopic detection of dysplastic lesions.

All reported studies on CE in patients with IBD have used

SD endoscopes.13 Recently, HD chromocolonoscopy has

been shown to only marginally increase the yield of overall

adenoma detection compared to HD white light colono-

scopy in patients undergoing surveillance colonoscopy for

colorectal polyps.15 No differences in dysplasia detection

in patients with colitis was noted between NBI and HD

colonoscopy in a study from the Netherlands.22 Studies

TABLE 1. Patient and Colonoscopy Information for SDand HD Colonoscopy

Variable

SDColonoscopy(n ¼ 160)

HDColonoscopy(n ¼ 209)

Age (mean 6 SD) years 49.7 (14.2) 50.8 (14.9)

Gender:

Male (%) 85 (53%) 121 (58%)

Female (%) 75 (47%) 88 (42%)

Diagnosis:

Crohn’s disease (%) 59 (37%) 63 (30%)

Ulcerative colitis (%) 101 (63%) 146 (70%)

Disease extent:)

Pancolitis (%) 50 (31%) 85 (41%)

Left sided UC (%) 50 (31%) 61 (29%)

Ileocolonic CD (%) 30 (19%) 37 (18%)

Colonic CD (% 30 (19%) 26 (12%)

5-Aminosalicylate use (%)* 130 (81%) 187 (89%)

Immunomodulator orbiological drug exposure (%)

79 (49%) 86 (41%)

Disease duration (mean 6 SD) 16.3 (8.4) 17.8 (8.6)

Adequacy of bowel preparation

Poor (%) 13 (8%) 15 (7%)

Fair (%) 42 (26%) 70 (34%)

Good (%) 77 (48%) 96 (46%)

Excellent (%) 28 (18%) 28 (13%)

Scoped beyond knownextent of disease

145 (91.2%) 196 (93.8%)

Grade of colonoscopist**

Consultant (%) 97 (61%) 86 (41%)

Nurse endoscopist (%) 47 (29%) 45 (22%)

Trainee (%) 16 (10%) 78 (37%)

Mean number of biopsies (SD) 13 (6) 14 (7)

*P ¼ 0.03; **P ¼ 0.01.

Inflamm Bowel Dis Detection of Dysplastic Lesions

3

comparing HD colonoscopy with HD chromocolonoscopy

in detecting dysplasia in long-standing colitis are therefore

needed to confirm if the added time taken and experience

needed for CE has any advantages over HD colonoscopy.

The advantage of HD colonoscopy over other techniques

like CE and NBI is that it should not increase the time

taken for the procedure and is likely to have better accep-

tance among endoscopists, as it involves familiar white

light color imaging and does not involve learning a new

skill.

Similar to most studies looking at detection of dys-

plastic lesions in patients with UC, the major proportion of

lesions detected in this study were low-grade dysplasia

(LGD).13 However, both techniques picked up a similar

proportion of lesions with LGD (25/32 [78%] by HD and

8/11 [73%] by SD colonoscopy), suggesting that the

increased yield with HD colonoscopy is probably a true

reflection of the increased yield with this technique.

Of the 11 lesions detected using SD colonoscopy,

five were on random biopsies and of the 32 dysplastic

lesions detected using HD colonoscopy five were on ran-

dom biopsies, suggesting that random biopsies will still

need to be taken with either modality. These results are

similar to the yield of random biopsies in a large retrospec-

tive study from the Netherlands where 24/125 (19%) of

dysplastic lesions (all low grade) were detected on random

biopsy.23 In the Dutch study, only one of four patients in

whom dysplasia was noted on random biopsies had any

long-term clinical consequence. In our study of the two

patients with LGD detected on random biopsies alone in

the HD group, no changes in clinical outcomes were noted.

Both these patients were placed on colonoscopic surveil-

lance and of these one had LGD reconfirmed on repeat sur-

veillance colonoscopy and the other is awaiting follow-up

colonoscopy. Further studies are needed to confirm if aban-

doning random biopsies would have long-term clinical

TABLE 2. Number of Dysplastic Lesions, Number of High Grade Dysplasia’s or Cancer’s, Number of Patients with Dys-plastic Lesions Detected on Targeted Biopsies, and Number of Patients with Flat Dysplastic Lesions Detected on Tar-geted Biopsies

Standard Definition High Definition

Total number of dysplastic lesions 11 (6 on targeted biopsies) 32 (27 on targeted biopsies)

Number of patients with dysplasia 8 24

Anatomic location of lesions:

Right Colon 04 (03 on targeted biopsies) 18 (16 on targeted biopsies)

03 (03 on targeted biopsies) 10 (07 on targeted biopsies)

Sigmoid/descending/transverse rectum 04 (00 on targeted biopsies) 04 (04 on targeted biopsies)

Number of patients with high grade dysplasia /cancer High grade dysplasia: 1 High grade dysplasia: 2

Cancer: 2 Cancer: 5

Number of patients with any dysplastic lesions detectedby targeted biopsies

5 22

Number of patients with flat dysplastic lesions detectedby targeted biopsy

2 11

TABLE 3. Multiple Regression Analysis of the Association Between Type of Colonoscopy (SD or HD) and Detection ofAny Dysplastic Lesions, High Grade Dysplasia or Cancer, Endoscopically Visible Dysplastic Lesions, and EndoscopicallyVisible Flat Dysplastic Lesions on a Per Patient Basis

PrevalenceRatio (95% CI) P-value

Adjusted PrevalenceRatio* (95% CI) P-value

Any dysplasia 2.30 (1.03-5.11) 0.04 2.21 (1.09-4.45) 0.03

High grade dysplasia or cancer 1.79 (0.48-6.91) 0.4 1.56 (0.42-5.79) 0.5

Any dysplastic lesions detected by targeted biopsies 3.37 (1.28-8.89) 0.01 2.99 (1.16-7.77) 0.02

Flat dysplastic lesions detected by targeted biopsies 4.21 (0.93-18.99) 0.06 2.64 (0.66-10.51) 0.16

*Adjusted for age, gender, diagnosis, duration of disease, extent of disease, 5-aminosalicylate use, immunomodulator or biologic drug exposure, numberof biopsies taken experience of colonoscopist, and bowel preparation noted.

Inflamm Bowel DisSubramanian et al

4

consequences, but improved targeted detection with HD

colonoscopy shows promise in reducing the need for ran-

dom biopsies in this patient population.

The retrospective nature of this study is another

potential limitation. We were not able to standardize the

collection of all data, such as withdrawal time, timing of

the procedure, and several endoscopists performed the pro-

cedure. However, the retrospective design could also be

considered a strength. The study provides information

regarding the yield of HD colonoscopy in actual clinical

practice. It has been argued that randomized controlled

studies in endoscopy are naturally biased, as endoscopists

perform the procedure more diligently than in routine clini-

cal practice as they feel they are being scrutinized. This

had led to the Institute of Medicine recommendations and

priorities on ‘‘comparative effectiveness research’’ includ-

ing colorectal cancer screening strategies to be done in rou-

tine clinical practice.24 As with all nonrandomized trials, it

is not possible to entirely exclude confounding variables;

however, we used appropriate statistical methods to

describe and account for differences in the populations

such as 5-aminosalicylate use and the proportion of trainee

colonoscopists performing the procedure. After accounting

for these differences, the dysplasia detection rate remained

different for HD versus SD colonoscopy. Not all the endo-

scopists used both modalities routinely. However, when the

analysis was limited to endoscopists who used both modal-

ities, 20 lesions (in 14 patients) were detected in 118 colo-

noscopies with HD colonoscopy, while no lesion was

picked up in 46 colonoscopies with SD colonoscopy, sug-

gesting that endoscopist skill alone could not explain the

differences noted in the study.

As this was a retrospective study, endoscopists were

not blinded to the clinical data and pathologists were not

blinded to the clinical and endoscopy data. Finally, we do

not have data on the false-positive rates in both SD and

HD colonoscopy, as lesions deemed nonsignificant were

less likely to have been recorded in the endoscopy report,

potentially causing underreporting of false-positive lesions

for both modalities. The median number of biopsies taken

in this study was 13 in the SD group and 14 in the HD

group. This is less than the recommended 33 biopsies that

are needed to achieve 90% confidence to detect dysplasia.4

As noted before, during the time period of this study the

British Society of Gastroenterology recommended taking

four quadrant biopsies every 10 cm2 and this was the pro-

tocol adopted by the endoscopy unit at Nottingham. How-

ever, this was not enforced and individual clinicians were

allowed to practice according to their clinical judgment.

The self-reported number of biopsies in a survey of UK

gastroenterologists revealed that 57% take fewer than 10

biopsies per patient.25 The St Mark’s group also reported a

median number of eight biopsies in their surveillance

program.26 Our figures are therefore representative of UK

clinical practice and can be generalizable to most clinical

practices. This could have led to lower identification of

dysplasia but, conversely, many studies have shown an

extremely low yield of dysplasia from nontargeted biopsies

compared to targeted biopsies, suggesting that the incre-

mental benefit from multiple nontargeted biopsies is

small.27,28

In conclusion, dysplasia yield was significantly higher

for HD colonoscopy compared to SD colonoscopy in

patients with long-standing colonic IBD. HD colonoscopy

was three times more likely to pick up a dysplastic lesion

on targeted biopsy than SD colonoscopy. No differences

were noted for the pick-up rate of lesions harboring HGD

or early cancer or visible flat lesions. Large multicenter

randomized controlled studies are needed to confirm the

findings of this study.

ACKNOWLEDGMENTSAuthor contributions: V.S., study design, data collec-

tion and analysis, wrote the article; V.R. and E.T., data

collection and analysis, critical review of the article; J.M.,

A.J., C.J.H., and K.R., study design, critical review of the

article.

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