Prospective, randomized comparison of 2 methods of cold snare polypectomy for small colorectal polyps

ORIGINAL ARTICLE
Prospective, randomized comparison of 2 methods of cold snare
polypectomy for small colorectal polyps
Akira Horiuchi, MD,1
Kenji Hosoi, MD,2
Masashi Kajiyama, MD,1
Naoki Tanaka, MD,1
Kenji Sano, MD,3
David Y. Graham, MD4
Komagane, Tokyo, Matsumoto, Japan; Houston, Texas, USA
Background: Both cold-only snare and hot polypectomy snare are used for the removal of small colorectal polyps.
Objective: To compare the outcome of cold snare polypectomy of small colorectal polyps with a snare
exclusively designed as a cold snare versus cold snare polypectomy by using a traditional polypectomy snare.
Design: Prospective, randomized, controlled study.
Setting: Municipal hospital in Japan.
Interventions: Patients with colorectal polyps 10 mm or smaller in diameter were randomized to dedicated cold
snare (dedicated cold snare group) or traditional cold snare (traditional cold snare group). The primary outcome
measure was complete resection rates by cold snaring based on pathological examination. Secondary outcomes
included bleeding within 2 weeks after polypectomy and identification of submucosal arteries and injured arteries
in the resected specimens.
Results: Seventy-six patients having 210 eligible polyps were randomized: dedicated cold snare group, N Z 37
(98 polyps) and traditional cold snare group, N Z 39 (112 polyps). Patient demographic characteristics including
the number, size, and shape of the polyps removed were similar in the 2 groups. The complete resection rate was
significantly greater with the dedicated cold than with the traditional cold snare (91% [89/98] vs 79% [88/112],
P Z .015), with a marked difference with 8- to 10-mm polyps, both flat and pedunculated. Immediate bleeding
and hematochezia rates were similar (19% vs 21%, P Z .86; 5.4% vs 7.7%, P Z .69). No delayed bleeding
occurred. Histology demonstrated a similar prevalence of arteries and injured arteries in the submucosa (33%
[32/96] vs 30% [31/104], P Z .59; 3.1% [3/96] vs 6.7% [7/104], P Z .24).
Limitations: Small sample size, single-center study.
Conclusion: Polypectomy by using a dedicated cold snare resulted in complete polyp removal more often than
did cold snaring with a traditional snare, especially polyps 8 to 10 mm in diameter, whether flat or pedunculated.
(Clinical trial registration number: NCT02036047.) (Gastrointest Endosc 2015;-:1-7.)
The success of colonoscopy for the prevention of colo-
rectal cancer is based on the ability to detect and remove pre-
cancerous lesions from the colon and rectum.1,2
Recently,
the Complete Adenoma Resection (CARE) study demon-
strated incomplete resection of 17.3% in 10- to 20-mm and
6.8% in 5- to 9-mm diameter polyps by using hot polypec-
tomy in the blended coagulation mode.3
That study
opened the way for continued discussions regarding
polypectomy technique.4
For example, a previous study
that used histology to assess colonoscopic resection of
diminutive polyps (%5 mm) compared cold snare
polypectomy and cold forceps and reported that the cold
snare method was significantly better (ie, 93.2% vs 75.9%,
P Z .009). However, in that study, failure of tissue retrieval
after cold snaring was noted in 6.8% of polyps,5
which was
Abbreviation: ASA, American Society of Anesthesiologists.
DISCLOSURE: All authors disclosed no financial relationships relevant
to this article.
Copyright ª 2015 by the American Society for Gastrointestinal Endoscopy
0016-5107/$36.00
http://dx.doi.org/10.1016/j.gie.2015.02.012
Received October 22, 2014. Accepted February 7, 2015.
Current affiliations: Digestive Disease Center, Showa Inan General Hospital,
Komagane, Japan (1), Department of Pediatrics, Juntendo University
Faculty of Medicine, Tokyo, Japan (2), Department of Laboratory
Medicine, Shinshu University Hospital, Matsumoto, Japan (3),
Department of Internal Medicine, Michael E. DeBakey VA Medical Center,
Baylor College of Medicine, Houston, Texas, USA (4).
Reprint requests: Akira Horiuchi, MD, Digestive Disease Center, Showa Inan
General Hospital, 3230 Akaho, Komagane 399-4117, Japan.
www.giejournal.org Volume -, No. - : 2015 GASTROINTESTINAL ENDOSCOPY 1

higher than the U.S. Multi-Society Task Force recommenda-
tion of more than 95% success polyp retrieval.6
One issue is how to accurately measure when a polyp is
completely resected because the endoscopist’s visual
impression is likely to be inaccurate.4
We previously
assessed complete resection rates after cold snare
polypectomy by using pathological examination and found
complete resection in 96% (95% confidence interval, 98%-
90%) of small polyps (1-8 mm) and 94% (95% confidence
interval, 97%-86%) of small polyps (1-10 mm) despite the
fact that the snares used in the 2 studies were different.7,8
In our experience, the success of resection and polyp
retrieval with cold snare polypectomy depends on both the
snare used and operator-related factors. It remains unclear
whether ease of resection and retrieval of specimens for path-
ological examination after cold snare polypectomy is more
related to the characteristics of the cold snare used or to
the type of polyp removed, pointing out the need for studies
comparing different snares that also take into account polyp
characteristics (eg, size, shape, histology).
Other issues with cold snare polypectomy relate to postpo-
lypectomy bleeding. Our previous comparison of cold and
hot polypectomy in anticoagulated patients found no de-
layed bleeding after cold snare polypectomy (78 polyps).8
However, endoscopic hemostasis for immediate and delayed
bleeding was required after hot polypectomy.8
We examined
whether the bleeding was related to injured submucosal
arteries and showed that the presence of histologically
demonstrable injured arteries in the submucosal layer after
cold snare polypectomy was significantly less than with hot
polypectomy (22% vs 39%, P Z .023). We hypothesized that
the difference in arterial damage was responsible for the
difference in delayed bleeding between the 2 techniques;
however, we have experienced delayed bleeding after cold
snare polypectomy for small colorectal polyps, even in the
absence of antithrombotic agents such that the relationship
between the snare used and the presence of injured
submucosal arteries is still an unanswered question.
The aim of this study was to compare cold snaring of
small colorectal polyps by using either a snare specifically
designed as a cold snare or cold snaring by using a tradi-
tional cold polypectomy snare. The study was based on
the hypothesis that cold polypectomy–specifically de-
signed snares with thinner wires are likely to resect colo-
rectal polyps more cleanly than is possible with
traditional cold polypectomy snares used without electro-
cautery and that this difference would result in an
increased complete resection rate and less damage to the
submucosal layer (ie, a lower delayed bleeding rate).
METHODS
Study design
This was a prospective, randomized, single-center com-
parison of 2 methods of cold polypectomies in patients
with small colorectal polyps by using a snare designed
only for cold polypectomy and 1 designed for cold or
hot polypectomy. The study was done at the Showa Inan
General Hospital in Japan. The Institutional Review Board
of Showa Inan General Hospital approved the study proto-
col, and all subjects gave written informed consent when
the procedure was scheduled. The study was reported ac-
cording to the CONSORT guidelines and was registered at
www.clinicaltrials.gov (NCT02036047).
Study population
Subjects referred and scheduled for screening, surveil-
lance, or diagnostic colonoscopy were prospectively
enrolled between January 2014 and June 2014; during
this time, 1393 patients underwent colonoscopy. Inclusion
criteria were patients with colorectal polyps up to 10 mm
in diameter. Exclusion criteria included age younger than
20 years, pregnant, history of colorectal surgical resection,
American Society of Anesthesiologists (ASA) class III and
IV, overweight (body weight O100 kg), or allergic to pro-
pofol or its components (soybeans or eggs). Those in
whom less than 90% of mucosa was seen due to a mixture
of semisolid and solid colonic contents were also excluded
because of poor bowel preparation. Antithrombotic agents
including antiplatelet agents and anticoagulant agents were
not discontinued in patients who were selected for this
study according to the basic policy of our endoscopy
unit. The patient parameters that were recorded included
demographic characteristics, indication for colonoscopy,
antithrombotic use, and history of abdominal surgery.
Enrolled patients were randomly assigned to 1 of the 2
polypectomy snares (dedicated cold snare group and tradi-
tional cold snare group) by using a computer-generated
random sequence if they qualified by having a polyp of
the appropriate size. If a patient had 1 or more polyps,
all eligible polyps were removed by using the initially as-
signed polypectomy snare.
Endoscopists and equipment
All procedures were performed by 1 of 2 experienced
endoscopists (having performed O10,000 colonoscopies
each). A pediatric variable-stiffness colonoscope (Olympus
PCF-Q260AZI; Olympus Medical Systems, Tokyo, Japan)
was used in all subjects. The instrument has a distal tip
diameter of 11.7 mm and an insertion tube diameter of
11.8 mm (working length, 133 cm; accessory channel diam-
eter, 3.2 mm). As is our standard practice, a transparent
short cap (Olympus D-201-12704) with an outer diameter
of 13.4 mm and an inner diameter of 12 mm was attached
to the tip of the colonoscope in an attempt to improve the
adenoma detection rate.9
The edge of the cap protrudes
approximately 4 mm beyond the tip of the colonoscope.
Retroflexion in the rectum was routinely performed.
The standard bowel preparation was performed by us-
ing 2 L of polyethylene glycol electrolyte lavage solution
plus ascorbic acid (Ajinomoto Pharmaceutical Co, Tokyo,
Cold-only vs traditional cold polypectomy snare Horiuchi et al
2 GASTROINTESTINAL ENDOSCOPY Volume -, No. - : 2015 www.giejournal.org

Japan) in all subjects. All of the procedures were
conducted under nurse-administered propofol sedation
(AstraZeneca, Osaka, Japan).10
Procedure
Cecal intubation was verified by identification of the ap-
pendiceal orifice and ileocecal valve. Endoscopists were in-
structed to measure polyp by using the size of the snare
catheter or the snare diameter. Polyps were measured in
increments of 1 mm. The time taken to reach the cecum,
the intubation rate of the terminal ileum, the procedure
time, the location of polyps (right side was defined as at
or proximal to the splenic flexure), and the size and
morphology (flat type was defined as height !2.5 mm as
measured by the diameter of the 2.4- or 2.6-mm snare cath-
eter) of each polyp were recorded. The size of polyp was
also estimated by using the open-forceps technique (for-
ceps span Z 7.3 mm). All colorectal polyps up to 10 mm
found, except for tiny hyperplastic polyps in the rectum
and distal sigmoid colon, were removed.
The dedicated cold snare (Exacto cold snare; US Endos-
copy, Mentor, Ohio) (Fig. 1, left) was designed to be used
exclusively for cold polypectomy snare and has a maximal
snare diameter of 9 mm. The traditional cold polypectomy
snare was the Snare Master snare (SD-210U-10; Olympus,
Tokyo, Japan) (Fig. 1, right) with a maximal snare
diameter of 10 mm that was designed for hot
polypectomy. The snare wire diameter of the Exacto cold
snare is 0.30 mm and 0.47 mm for the Snare Master
snare. The instrument was rotated for polypectomy to
align the polyp with the instrument channel at the 6
o’clock position. The snare was opened enough to allow
a rim of normal tissue to be ensnared and resected
(Fig. 2A). The colonoscope was angled into the colon
wall while the snare was pushed forward. The polyp and
small rim of normal tissue were snared closely without
tenting and guillotined (Fig. 2B). If submucosa tissue was
trapped, the captured tissue was guillotined repeatedly
to remove the polyp completely. The absence of visible
residual polyp tissue was also confirmed endoscopically
(Fig. 2C) and by using narrow-band imaging (Fig. 2D)
before the completeness of the polyp resection was
determined pathologically. If the residual polyp was seen
at the polypectomy site, it was resected again. The
transected small polyps (%6 mm) were sucked into a
trap. Larger resected polyps (R7 mm) were retrieved by
using retrieval forceps without the use of the endoscopic
suction channel to avoid fragmenting the samples.
When snaring a pedunculated polyp, the snare was
placed approximately half way up the stalk, and the stalk
was cut. Submucosal injection of saline solution before
polyp removal was not performed. Prophylactic clipping af-
ter polyp removal was not routinely performed; however,
hemostatic clipping was carried out during the procedure
for immediate bleeding. When a vessel was visible after
the removal of a polyp of the pedunculated type, hemo-
static clipping was also performed.
The size, shape, and location of all polyps were
recorded. All patients who underwent polypectomy visited
our hospital 2 weeks after polypectomy to be informed of
the pathological results of polyps removed. Adverse events
and all GI symptoms within 2 weeks after each polypec-
tomy were recorded.
Pathological examination
The pathologist (K.S.) remained blinded to the snare
used for the cold snare polypectomy in this study (dedi-
cated cold polypectomy snare or conventional cold poly-
pectomy snare) until after all the analyses were
completed. After removal, excised specimens were
mounted with pins on Styrofoam plates and fixed in 10%
formalin. They were examined grossly, and after
sectioning, they were examined by using hematoxylin
and eosin staining. The resection was considered complete
histologically if vertical and lateral margins were free of
neoplasia tissue. The submucosal layer of the resected
specimens was also specifically examined for the presence
of arteries and injured arteries.
Outcome variables
The primary outcome measure was a comparison of the
rate of complete resection of colorectal polyps as assessed
by pathological examination. Secondary outcome mea-
sures were postpolypectomy bleeding within 2 weeks after
cold snare polypectomy and the presence of arteries and
injured arteries in the submucosal layer in the resected
specimens. When delayed bleeding was suspected without
a decrease in hemoglobin, the bleeding was judged to be
slight postpolypectomy bleeding, which was designated
as hematochezia. Immediate bleeding that requires
Figure 1. Left, Dedicated cold polypectomy snare (Exacto cold snare, US
Endoscopy, Mentor, Ohio). Right, Traditional cold polypectomy snare
(Snare Master, Olympus, Tokyo, Japan).
Horiuchi et al Cold-only vs traditional cold polypectomy snare

hemostatic clipping was defined as spurting or oozing that
continued for more than 30 seconds.
Sample size calculation and statistical analysis
Sample size calculation was based on the primary
outcome measure of the study. Our previous studies found
that the complete resection rates of cold snare polypec-
tomy based on the pathological examination were 96%
for small polyps of 1 to 8 mm and 94% for small polyps
of 1 to 10 mm.7,8
Based on this experience, we hypothe-
sized that the complete resection rate of relatively larger
polyps (8-10 mm) by cold snaring by using the exclusively
cold polypectomy snare to be more than 94%, whereas
that of the traditional cold polypectomy snare would be
80%. We assumed that the dedicated cold snare group
would increase the complete resection rate of polyps by
at least 14% compared with the traditional cold snare
group. At least 90 polyps per group were required to
demonstrate a superior complete resection rate of the
dedicated cold snare group compared with the traditional
cold snare group, with a Z .05 and a power of 80%. Statis-
tical differences were analyzed by c2
tests of independence
and the Fisher exact test or the Student t test. P values!.05
were considered significant. Statistical analysis was per-
formed by using JMP 9.0.2 version software (SAS Institute
Inc, Cary, NC).
RESULTS
Patients
Eighty-three patients were recruited for the study. Seven
patients who had a polyp larger than 10 mm found during
the procedure were dropped from the study; therefore 76
patients (dedicated cold snare group; N Z 37 and tradi-
tional cold snare group, N Z 39) were enrolled and under-
went polypectomy. Patient demographic characteristics,
indications for colonoscopy, and the use of antithrombotic
agents were similar between the 2 techniques (Table 1).
For subjects with more than 1 polyp, each polypectomy
was considered to be independent of the others.
Polypectomy
There were no significant differences in the cecal intuba-
tion rate, the mean cecal intubation time, the intubation
rateofterminalileum,and themeanprocedure timebetween
the dedicated cold snare group and the traditional cold snare
group (Table 2). The characteristics of number, size, and
shape of polyps removed are shown in Table 2 and were
also similar between the 2 techniques (dedicated cold snare
group: 98 polyps; average size, 6.5 mm; median size,
6.5 mm; traditional cold snare group: 112 polyps; average
size, 6.3 mm; median size, 6 mm).
Figure 2. A, The snare is opened enough to allow a rim of normal tissue to be ensnared and resected. B, The polyp and small rim of normal tissue are
snared without tenting and guillotined vigorously. C, The absence of visible residual polyp tissue was confirmed endoscopically. D, Removal confirmed by
using narrow-band imaging.

The complete resection rate in the dedicated cold snare
group was significantly higher than that in the traditional
cold snare group (91% [89/98] vs 79% [88/112], P Z
.015) (Table 2). The complete resection rates for polyps
8 to 10 mm in diameter and either flat or pedunculated
in morphology, and adenoma or sessile serrated
adenoma/polyp in the dedicated cold snare group were
significantly greater than those of in traditional cold
snare group (83% [15/18] vs 45% [10/22], P Z .014)
(Table 3). After resection, residual polyps were seen in 3
lesions in the dedicated cold snare group and 8 lesions
in the traditional cold snare group. All 11 residual polyps
were re-resected endoscopically, and all were defined as
incomplete resection pathologically. When the incom-
pletely resected polyps were adenomas or sessile serrated
adenoma/polyps, these patients were scheduled to un-
dergo colonoscopy 1 year after polypectomy.
There was no significant difference in the mean number
per patient of prophylactic hemostatic clips used after
polypectomy in the 2 groups. The occurrence of immedi-
ate bleeding and hematochezia during the both proce-
dures was similar (19% vs 21%, P Z .86; 5.4% vs 7.7%,
P Z .69). No delayed bleeding occurred in either group
(Table 2). All 5 patients with hematochezia (mild
uninvestigated bleeding) in both groups were also users
of antithrombotic agents. No perforation was observed in
either group.
Pathological examination
Tissue could be examined for arteries in the submucosal
layer in 98% (96/98) and 93% (104/112) of resected polyps
in the dedicated cold snare group and traditional cold
snare group, respectively (Table 4). Submucosal arteries
detected in the submucosal layer were similar between
the traditional cold snare group and the dedicated cold
snare group (33% [32/96] vs 30% [31/104], P Z .0.59)
(relative risk, 1.1; 95% confidence interval, 0.74-1.7).
There were fewer injured arteries detected in the
submucosal layer in the dedicated cold snare group than
in the traditional cold snare group, but the difference
was not significant (3.1% [3/96] vs 6.7% [7/104], P Z
.24) (relative risk, 0.46; 95% confidence interval, 0.12-
1.7). In all 5 patients with hematochezia (mild
uninvestigated bleeding) in both groups, the injured
arteries were detected in the submucosal layer in the
resected specimens.
DISCUSSION
Cold snare polypectomy is frequently used for small
polyps (%10 mm). However, it is often difficult to
completely remove polyps 10 mm in diameter and flat or
pedunculated in morphology by using cold snaring without
TABLE 1. Comparison of baseline characteristics in patients using the
dedicated cold polypectomy snare and traditional cold polypectomy
snare
Characteristic
Group
P
value
Dedicated
cold snare
Traditional
cold snare
No. of patients 37 39
Age, mean (SD), y* 66.4 (13) 69 (10) .87
Femaley 10 15
Indication, no. (%)y .70
Hemo-positive stool 25 (68) 24 (62)
Screening 8 (22) 12 (31)
Other 4 (11) 3 (8)
Antithrombotic agents
used, no. (%)y
4 (11) 4 (10) .94
Warfarin 2 (5) 1 (3)
Dabigatran 1 (3) 0
Aspirin 1 (3) 3 (8)
*Differences between dedicated cold snare group and traditional cold snare group
compared by the Student t test for continuous variables.
yDifferences between dedicated cold snare group and traditional cold snare group
compared by the c2
test for categorical data.
TABLE 2. Comparison of outcomes and adverse events in patients
using the dedicated cold polypectomy snare and traditional cold
polypectomy snare
Group
P
value
Dedicated
cold snare
Traditional
cold snare
Cecal intubation rate, %* 100 100
Cecal intubation time, miny 5.6 (5) 5.4 (6) .67
Intubation rate of terminal
ileum, %*
89 87 .79
Procedure time, mean (SD), miny 17 (8) 18 (9) .88
Total no. of polyps removed 98 112
No. of polyps removed per
patient, mean (SD)
2.6 (1.8) 2.9 (2.4) .68
Polyp size, mm, mean (SD) 6.5 (1.8) 6.3 (2.2) .32
Median polyp size, mm 6.5 6.0 .81
Complete resection rate, %* 91 (89/98) 79 (88/112) .015
No. of hemostatic clips per
patient, mean (SD)y
0.28 (1.0) 0.35 (0.8) .37
Postpolypectomy bleeding, %*
Immediate bleeding 19 (7/37) 21 (8/39) .86
Hematochezia 5.4 (2/37) 7.7 (3.39) .69
Delayed bleeding 0 0
Total 24 (9/37) 28 (11/39) .70
Perforation 0 0
Hematochezia (mild uninvestigated bleeding) and delayed bleeding within 2 weeks
after each polypectomy were recorded.
compared by the c2

electrocautery. This study demonstrated that the complete
resection rate of small polyps (%10 mm) by using a snare
designed exclusively for cold polypectomy was significantly
better than when using a traditional cold polypectomy
snare for cold snaring (91% [89/98] vs 79% [88/112], P Z
.015). In particular, the rate of complete resection was
highest in polyps 8 to 10 mm in diameter that were flat
or pedunculated in morphology (83% [15/18] vs 45% [10/
22], P Z .014).
The difference in the complete resection rates with the
2 types of snares used in this study is possibly related to
the different characteristics of the snares, likely the differ-
ences in the diameter and shape of the snare wire (Exacto
cold snare, 0.30 mm, diamond-shaped; Snare Master snare,
0.47 mm, oval shape). The Exacto cold snare was designed
specifically to be used for cold resection, and the device
was tested and validated for this indication. It cannot be
used for hot snaring is the sheath/catheter, which is not
thermally/electrically insulated. We postulate that the
design of the device, such as thinner wire and/or shield
shape, may be more effective for cold resection than that
of the traditional cold polypectomy snare and result in
more cutting than tearing through the mucosa or stalk,
thus making resection of the polyp technically easy.
The definitions of complete resection rate and
incomplete resection rate have not been standardized.
One previous method of determining complete resection
was to take 2 or more additional biopsy specimens from
the base or edges of the polypectomy site for microscopic
examination.3-5
We used an adenoma-free condition of the
horizontal margins of the resected specimen as seen on
pathological examination as our definition of complete
resection of the polyp removed. In Japan, irrespective of
the size of polyps, excised specimens of polypectomy as
well as EMR were mounted with pins on Styrofoam plates
and fixed in 10% formalin and submitted for pathological
examination. Japanese pathologists are trained to examine
the lateral margin of all polyps and to report the results of
the completeness of resection. Our pathologist is
experienced in this and has participated in our previous
studies.
The status of horizontal margins of the resected polyps
8 to 10 mm in diameter and flat or pedunculated was his-
tologically unclear more frequently after the use of the
traditional cold polypectomy snare than with the dedicated
cold snare (Table 3). We used cold snare polypectomy for
all small polyps (%10 mm), irrespective of their shape.
However, electrocautery is often used for pedunculated
and bulky sessile polyps in the 6- to 10-mm diameter
range with the thought that it is likely more effective
than cold snaring.11,12
This study showed that the snare de-
signed exclusively for cold polypectomy provided excellent
results with pedunculated polyps 8 to 10 mm in diameter
and electrocautery was unnecessary.
Cold snare polypectomy has been previously reported
to be associated with a low rate of postpolypectomy
bleeding.13,14
We speculated that the cause of delayed
bleeding was related to injury of blood vessels in the sub-
mucosa layer caused by snaring. In a previous study, we
TABLE 3. Comparison of complete resection rate of polyps removed
in patients by using the dedicated cold polypectomy snare and
traditional cold polypectomy snare
Complete resection rate, %
P value
Dedicated cold
snare group
Traditional cold
snare group
Total 91 (89/98) 79 (88/112) .015
Size, mm
%5 92 (35/38) 91 (41/45) .87
6-7 93 (39/42) 82 (37/45) .14
8-10 83 (15/18) 45 (10/22) .014
Location
Left colon 95 (38/40) 82 (40/49) .06
Right colon 88 (51/58) 76 (48/63) .10
Shape
Flat 74 (17/23) 42 (8/19) .037
Sessile 96 (64/67) 91 (74/81) .32
Pedunculated 100 (8/8) 50 (6/12) .017
Pathology
High-grade adenoma 100 (1/1)
Adenoma 89 (75/84) 78 (73/94) .039
SSA/P 100 (5/5) 50 (3/6) .064
Hyperplastic polyp 100 (9/9) 100 (11/11)
Differences between dedicated cold snare group and traditional cold snare group
compared by the c2
SSA/P, sessile serrated adenoma/polyp.
TABLE 4. Comparison of artery in submucosal layer in resected
specimens with the dedicated cold polypectomy snare and traditional
cold polypectomy snare
Group
P value RR (95% CI)
Dedicated
cold snare
group
Traditional
cold snare
group
Total no. of polyps
examined
96 104
Polyp size, mm,
mean (SD)*
6.5 (1.7) 6.4 (2.3) .33
Presence of arteries
in submucosay
33% (32/96) 30% (31/104) .59 1.1 (0.74-1.7)
Presence of injured
arteries in
submucosay
3.1% (3.96) 6.7% (7/104) .24 0.46 (0.12-1.7)
RR, Relative risk (presence in dedicated cold snare/presence in traditional cold snare);
CI, confidence interval.
compared by c2

demonstrated that injured submucosal arteries were seen
significantly less frequently after cold snare polypectomy
than after hot polypectomy (22% vs 39%, P Z .023).8
This difference was also consistent with the increase in
delayed bleeding associated with hot compared with cold
polypectomy.8
This study compared 2 different types of
snare for cold snaring, and histologically injured arteries
were present in the submucosal layer in both groups.
Although the difference was not significantly different,
the rate was lower with the thinner, specially designed
cold snare (3.1% [3/96] vs 6.7% [7/104], P Z .24). In
addition, the mean number of patients receiving
prophylactic hemostatic clips and the frequency of
postpolypectomy bleeding with the thin wire was also
lower than with the hot snare, but again the differences
were not significant (0.28 vs 0.35, P Z .37; 24% vs 28%,
P Z .70). We excluded ASA class III patients because
ASA class III patients with severe systemic diseases were
expected to possibly affect postpolypectomy bleeding
rates. Larger studies including ASA class III patients are
needed to clarify whether the snare characteristics are an
important variable in this regard.
The use of a transparent cap in all cases has implications
related to the external validity of the study because a trans-
parent cap is not routinely used in the West for screening
colonoscopy. In addition to an increased adenoma detec-
tion rate, it is possible that the use of the cap may facilitate
polypectomy. We do not believe that the use of a trans-
parent cap affects the primary and secondary outcome
measures of this study; however, a randomized compari-
son would be required if the issue were considered impor-
tant enough.
If a small (%10 mm) polyp is detected and removed
with an exclusively designed cold snare and then a second
larger polyp is seen, it may be necessary to use a second
hot snare for hot polypectomy. This would double the
cost of the devices per colonoscopy. The cost of the Exacto
cold snare in Japan is also 1.5 times higher than that of
Snare Master (4500 JPY vs 3000 JPY). The Exacto cold snare
cannot be used for hot polypectomy because it was not de-
signed with attachments for electrocautery. It is unknown
whether the sheath is insulated for electrocautery. There-
fore, the use of an exclusively designed cold snare could
increase the cost of polypectomy compared with that of
a traditional cold polypectomy snare but with the advan-
tage that fewer resections will leave residual polyp
material.
This study has some limitations. The study could not be
blinded because the endoscopist knew the type of snare
used. It is possible that there was bias due to the different
techniques used or other preexisting bias of the investiga-
tors. In addition to a relatively small sample size, the study
was conducted at a single hospital and will need to
be confirmed in multicenter studies and in different
populations. We also examined only 1 specially designed
snare and 1 traditional cold polypectomy snare. Ideally, a
snare could be developed that included the best character-
istics of both.
In conclusion, the complete resection rate by using a
snare designed exclusively for cold polypectomy was better
than a snare designed for traditional cold polypectomy.
The cold snare technique by using the thinner snare was
especially designed for cold snaring and obtained a higher
proportion of with complete adenoma removal than cold
snaring with a traditional cold polypectomy snare with
used for colorectal polyps 8 to 10 mm in diameter whether
flat or pedunculated. In clinical practice, the majority of
colorectal polyps encountered are less than 10 mm in
diameter, suggesting that cold snare polypectomy with a
specially designed snare would improve polypectomy
results and likely result in more successful prevention of
colorectal cancer.
REFERENCES
1. Winawer SJ, Zauber AG, Ho MN, et al. Prevention of colorectal cancer
by colonoscopic polypectomy. The National Polyp Study Workgroup.
N Engl J Med 1993;329:1977-81.
2. Citarda F, Tomaselli G, Capocaccia R, et al. Italian multicentre study
group. The Italian Multicentre Study Group: Efficacy in standard clinical
practice of colonoscopic polypectomy in reducing colorectal cancer
incidence. Gut 2001;48:812-5.
3. Pohl H, Srivastava A, Bensen SP, et al. Incomplete polyp resection dur-
ing colonoscopy- results of the complete adenoma resection (CARE)
study. Gastroenterology 2013;144:74-80.
4. Liu S, Ho SB, Krinsky ML. Quality of polyp resection during colonos-
copy: are we achieving polyp clearance? Dig Dis Sci 2012;57:1786-91.
5. Lee CK, Shim JJ, Jang JY. Cold snare polypectomy vs. cold forceps
polypectomy using double-biopsy technique for removal of
diminutive colorectal polyps: a prospective randomized study. Am J
Gastroenterol 2013;108:1593-600.
6. Rex DK, Bond JH, Winawer S, et al. U.S. Multi-Society Task Force on
Colorectal Cancer: Quality in the technical performance of
colonoscopy and the continuous quality improvement process for
colonoscopy: recommendations of the U.S. Multi-Society Task Force
on Colorectal Cancer. Am J Gastroenterol 2002;97:1296-308.
7. Ichise Y, Horiuchi A, Nakayama Y, et al. Prospective randomized
comparison of cold snare polypectomy and conventional polypectomy
for small colorectal polyps. Digestion 2011;84:78-81.
8. Horiuchi A, Nakayama Y, Kajiyama M, et al. Removal of small colorectal
polyps in anticoagulated patients: a prospective randomized
comparison of cold snare and conventional polypectomy. Gastrointest
Endosc 2014;79:417-23.
9. Horiuchi A, Nakayama Y, Kajiyama M, et al. Benefits and limitations of
cap-fitted colonoscopy in screening colonoscopy. Dig Dis Sci 2013;58:
534-9.
10. Horiuchi A, Nakayama Y, Fujii H, et al. Psychomotor recovery and blood
propofol level in colonoscopy when using propofol sedation. Gastro-
intest Endosc 2012;75:506-12.
11. Fyock CJ, Draganov PV. Colonoscopic polypectomy and associated
techniques. World J Gastroenterol 2010;16:3630-7.
12. Hewett DG. Colonoscopic polypectomy: current techniques and
controversies. Gastroenterol Clin North Am 2013;42:443-58.
13. Deenadayalu VP, Rex DK. Colon polyp retrieval after cold snaring.
Gastrointest Endosc 2005;62:253-6.
14. Repici A, Hassan C, Vitetta E, et al. Safety of cold polypectomy
for !10 mm polyps at colonoscopy: a prospective multicenter
study. Endoscopy 2012;44:27-31.

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