Keywords
endoloop-assisted endoscopic resection - endoscopic submucosal dissection - large
pedunculated polyps
Introduction
In the past few decades, colonoscopic polypectomy has become an effective tool for
preventing colorectal cancer,[1]
[2] and most polyps can be removed under colonoscopy instead of surgery. In total, 76
to 90% reduction in incidence of colon cancer and 53% reduction in cancer-related
mortality are attributed to colon polypectomy.[1]
[3] However, complications including bleeding, perforation, and postpolypectomy coagulation
syndrome can be observed during this procedure.[4]
[5]
[6]
[7] According to some research, postpolypectomy bleeding (PPB) is the most common complications
of colonoscopic polypectomy, with an incidence ranging from 0.3 to 6.1%.[8] The incidence of PPB after resection of large pedunculated polyps can reach up to
15% due to the large feeding vessels traversing the stalk.[9]
[10]
[11]
[12] Therefore, several preventive methods including injection adrenaline or epinephrine
to the stalk as well as application of endoloop or hemoclip have been developed.[13]
[14]
[15]
[16] Effective comparisons between these preventive methods have been carried out. Kouklakis
et al found that endoloop and hemoclip were more effective than adrenaline injection
alone in preventing bleeding complication.[11] The application of a prophylactic clip was as effective and safe as an endoloop
in the prevention of PPB.[16] However, the use of endoloop is technically more difficulty than hemoclip application,
especially in the left colon.[15]
[16] Underwater endoloop-assisted endoscopic resection was performed to solve this difficult
problem, but this method still needs further research to verify its effectiveness
and safety.[17] Besides, endoscopic submucosal dissection (ESD) has also been proven to be safe
and effective for resection of large pedunculated polyps.[18] However, there has been no study evaluating the effectiveness and safety of endoloop-assisted
endoscopic resection and ESD. The aim of the present study was to compare the effectiveness
and safety of endoloop-assisted endoscopic resection and ESD in patients with large
pedunculated colorectal polyps.
Patients and Methods
Patients
This study was a single-center retrospective study in Jiangsu Province Hospital of
Traditional Chinese Medicine. We retrospectively analyzed 124 patients with large
pedunculated polyp (≥15 mm in head diameter, ≥5 mm in stalk diameter, and ≥5 mm in
stalk length) treated at our digestive endoscopy center from 2014 to 2024 year. One
hundred and twenty-four patients were divided into two groups: group A received ESD
(62 cases) and group B received endoloop-assisted endoscopic resection (62 cases).
Ethics Statement
This study was approved by the Ethics Committee of Affiliated Hospital of Nanjing
University of Chinese Medicine, Nanjing, China, and written informed consent was obtained
from all participants.
Endoloop-Assisted Endoscopic Resection and ESD Procedure
All procedures were performed by experienced doctors from our center. The compositions
of an endoloop system include an operating part and an attached loop. The loop is
retracted inside the plastic sheath for insertion through the accessory channel of
the colonoscope before operation. The polyp was adjusted to the six o'clock position
on the screen by manipulating the colonoscope. After the loop had been extended and
applied at the base of the stalk, it was tightened around the stalk by sliding the
stopper. After the color of the polyp head changed to dark red, the loop was detached
from the operating part. Then, we used a diathermic snare to sever the stalk of the
polyp above the tightened loop by electrosurgical coagulation current ([Fig. 1]).
Fig. 1 The procedure of endoloop-assisted endoscopic resection.
ESD was performed by experienced endoscopists in our center. After injecting 0.01%
adrenaline melamine injection, a mucosal flap was created at the anal side by a DualKnife
(KD-650L; Olympus) with a VIO 300D high-frequency generator (ERBE, Tübingen, Germany),
following which the dissection proceeded to the center of the polyp. Finally, the
circumferential mucosal incision was completed, and the submucosal dissection was
accomplished. Endoscopic hemostasis was achieved with the tip of the DualKnife. When
hemostasis could not be achieved with the DualKnife alone, hemostatic forceps were
used ([Fig. 2]).
Fig. 2 The procedure of endoscopic submucosal dissection.
Study Outcomes
The primary endpoint of the study was the rate of PPB in each group. PPB included
both immediate PPB (IPPB) and delayed PPB (DPPB). IPPB was defined as intraprocedural
hemorrhage occurring immediately after polyp resection. Hemostatic techniques were
chosen based on the physician's experience and preference. DPPB was defined as occurring
when hematochezia or melena was observed after a colonoscopic procedure within 30
days. The secondary outcome included operation time, hospitalization time, and the
number of clips used.
Statistical Analysis
SPSS software version 19.0 was used for statistical analysis (SPSS Inc., Chicago,
Illinois, United States). Continuous data were compared by unpaired Student's t-test. The categorical variables were tested using corrected chi-squared or two-tailed
Fisher's exact tests. A p-value of ≤0.05 was considered statistically significant.
Results
-
The baseline characteristic of the two groups: The baseline characteristic included
sex, age, location, mean size of the polyp head, and histopathology. There was no
significant differences in baseline characteristics between two the groups ([Table 1]).
-
The incidence of IPPB and DPPB in the two groups: Two patients in group A experienced
IPPB and one experienced DPPB, while four patients in group B experienced IPPB and
no case of DPPB ([Table 2]).
-
The operation time, hospitalization time, and number of clips used in the two groups:
The operation time and hospitalization time in group A were all significantly shorter
than those in group B. The number of clips used in group A was less than that used
in group B ([Table 3]).
Table 1
The baseline characteristic of two groups
|
Group A
|
Group B
|
p-value
|
|
Sex
|
|
Male
|
43
|
52
|
0.057
|
|
Female
|
19
|
10
|
|
Age (y), mean ± standard deviation (SD)
|
59.85 ± 11.73
|
56.08 ± 13.80
|
0.103
|
|
Location
|
|
Rectum
|
4
|
1
|
0.807
|
|
Sigmoid colon
|
37
|
42
|
|
Descending colon
|
4
|
6
|
|
Transverse colon
|
11
|
7
|
|
Ascending colon
|
6
|
6
|
|
Size of the head (cm), mean ± SD
|
2.40 ± 0.55
|
2.30 ± 0.53
|
0.268
|
|
Histopathology
|
|
|
0.051
|
|
Hyperplastic polyp
|
1
|
2
|
|
Inflammatory polyp
|
1
|
0
|
|
Juvenile polyp
|
2
|
4
|
|
Low-grade intraepithelial neoplasia (LGIN)
|
12
|
25
|
|
High-grade intraepithelial neoplasia (HGIN)
|
46
|
31
|
Table 2
The incidence of IPPB and DPPB in two groups
|
Group A
|
Group B
|
p-value
|
|
Group A
|
Group B
|
p-value
|
|
IPPB (+)
|
2
|
4
|
0.68
|
DPPB (+)
|
1
|
0
|
1.0
|
|
IPPB (–)
|
60
|
58
|
DPPB (–)
|
61
|
62
|
Abbreviations: DPPB, delayed postpolypectomy bleeding; IPPB, immediate postpolypectomy
bleeding.
Table 3
The operation time, hospitalization time, and number of clips used in two groups
|
Group A
|
Group B
|
p-value
|
|
Operation time (min)
|
29.31 ± 5.64
|
23.87 ± 3.97
|
<0.001
|
|
Hospitalization time (d)
|
7.14 ± 1.1
|
5.98 ± 1.18
|
<0.001
|
|
Number of clips
|
5.58 ± 1.3
|
2.37 ± 0.71
|
<0.001
|
Discussion
To our knowledge, this study is the first trial to investigate the difference between
ESD and endoloop-assisted endoscopic resection. Our study compared the efficacy of
ESD versus endoloop-assisted endoscopic resection in preventing IPPB, DPPB, operation
time, hospitalization time, and the number of clips used in large, pedunculated colonic
polyps. The outcomes show that there is no significant difference in the efficacy
of preventing IPPB and DPPB. However, the operation time and hospitalization time
in group A were all significantly shorter than those in group B. The number of clips
used in group A was less than that in group B.
Colonic adenomatous polyp is a precancerous disease of the colon that can transform
into cancer through genetic and epigenetic pathways (adenoma–carcinoma sequence).[19] Endoscopic polypectomy, a gold standard in removing polyps, reduces the need for
surgery and has been shown to be effective in preventing the development of colorectal
cancer.[1] However, the method used for endoscopic polypectomy depends rather on the experience
of the endoscopist and there are some inevitable complications.
PPB is the most common adverse event of colonoscopic polypectomy. The higher incidence
of IPPB and DPPB in large pedunculated colonic polyps is attributed to the presence
of a large blood vessel within the stalk.[20] To reduce PPB of large pedunculated polyps, mechanical prevention and injection
therapy have been performed and research has indicated that injection therapy is inferior
to mechanical prevention.[11] Besides, the effectiveness of hemoclip only in preventing PPB is not inferior to
the combination of hemoclip and injection treatments,[21] indicating that PPB can be effectively prevented by mechanical prevention alone.
ESD technology has matured and can provide a clear field of vision. Recently, colorectal
ESD has been accepted as an effective and safe procedure.[18]
[22] In this study, we compared the efficacy and safety of endoloop-assisted endoscopic
resection and ESD for large pedunculated polyps. The results indicated that there
was no significant difference in the efficacy of preventing IPPB and DPPB. However,
the operation time and hospitalization time in group A were all significantly shorter
than those in group B. The number of clips used in group A was less than that in group
B. However, for difficult areas with poor visibility such as splenic curvature and
a large polyp head or lobulated polyp head, ESD can serve as an alternative solution
to provide effective and safe treatment for patients.
There are some limitations to the study. The retrospective design of the study may
present selection bias, but all patients were treated by experienced Chinese endoscopists
and none of the patients required surgical treatment due to serious adverse events
within the established indications.
In conclusion, our study showed that there was no difference between endoloop-assisted
endoscopic resection and ESD in preventing the incidence of IPPB and DPPB. Although
the operation time and hospitalization time were shorter and the number of clips used
was less in endoloop-assisted endoscopic resection, ESD can be an effective and safe
alternative for difficult areas with poor visibility or polyps with large or lobulated
heads.
