Effect of sigmoidectomy in treating sigmoid colon cancer: A protocol of systematic review

Abstract

Background:
This study will assess the effect of sigmoidectomy in treating sigmoid colon cancer (SCC).

Methods:
This study will search the following databases from inception to the present: MEDLINE, EMBASE, Cochrane Library, CINAHL, PsycINFO, Scopus, OpenGrey, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. All electronic databases will be searched with no restrictions of language. Two researchers will independently handle all study selection, data extraction, and risk of bias, respectively. Any disparities between 2 researchers will be figured out by a third researcher through discussion. RevMan 5.3 software will be used for statistical analysis in this study.

Results:
This study will provide a high-quality synthesis of targeted outcomes to evaluate the efficacy and complications of sigmoidectomy in treating SCC.

Conclusion:
The results of this study will provide evidence to judge whether sigmoidectomy can benefit patients with SCC.

Study registration on osf:
osf.io/dpxkg.

Full text

Effect of sigmoidectomy in treating sigmoid colon
cancer
A protocol of systematic review
Hua-ping Hou, MM
a
, Pu-guo Gui, MB
b,∗
Abstract
Background: This study will assess the effect of sigmoidectomy in treating sigmoid colon cancer (SCC).
Methods: This study will search the following databases from inception to the present: MEDLINE, EMBASE, Cochrane Library,
CINAHL, PsycINFO, Scopus, OpenGrey, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. All
electronic databases will be searched with no restrictions of language. Two researchers will independently handle all study selection,
data extraction, and risk of bias, respectively. Any disparities between 2 researchers will be figured out by a third researcher through
discussion. RevMan 5.3 software will be used for statistical analysis in this study.
Results: This study will provide a high-quality synthesis of targeted outcomes to evaluate the efficacy and complications of
sigmoidectomy in treating SCC.
Conclusion: The results of this study will provide evidence to judge whether sigmoidectomy can benefit patients with SCC.
Study registration on OSF: osf.io/dpxkg.
Abbreviations: CC =colon cancer, CIs =confidence intervals, RCTs =randomized controlled trials, SCC =sigmoid colon
cancer.
Keywords: effect, sigmoid colon cancer, sigmoidectomy
1. Introduction
Colon cancer (CC) is one of most common malignancy tumors
and also the leading cause of cancer-related death globally.
[1]
At
initial stage, about 10% patients with CC have a primary tumor
proceeding to adjacent tissues.
[2]
Sigmoid colon is the final section
of colon before rectum, and shaped like an “S.”
[3,4]
Sigmoid
colon cancer (SCC), a type of CC, occurs in the sigmoid colon
section.
[3,5–7]
Its symptoms are mostly mild or inconspicuous at
the early stage, and thus are not easily to be detected.
[8]
At the
middle and late stages, it manifests as persistent abdominal
discomfort, dull pain, bloating, constipation, and intestinal
obstruction.
[9,10]
Thus, it is very important to diagnose and treat
at early stage.
Surgery is the principal treatment of SCC.
[11–13]
A variety of
previous clinical studies have reported to use sigmoidectomy for
the treatment of SCC.
[14–24]
However, there is still insufficient
evidence-based medicine evidence to support sigmoidectomy for
SCC. Therefore, this study will comprehensively and systemati-
cally assess the effect of sigmoidectomy in treating SCC.
2. Methods
2.1. Dissemination and ethics
We will plan to submit this study at a peer-reviewed journal or a
relevant conference. No ethic approval document is needed
because this study will not employ any individual data.
2.2. Study registration
We have registered on OSF (osf.io/dpxkg). It will be conducted
according to the guidelines of Cochrane Handbook for
Systematic Reviews of Interventions and the Preferred Reporting
Items for Systematic Reviews and Meta-Analysis Protocol
statement.
[25]
2.3. Inclusion criteria for study selection
2.3.1. Types of studies. All relevant randomized controlled
trials (RCTs) of sigmoidectomy in treating SCC will be included
without restrictions of language and publication status.
2.3.2. Types of participants. Inclusion criteria for study
participants will be all eligible patients who were diagnosed as
This study has been supported by the Shaanxi Key R&D Program (No. 2017SF-
207). The funder did not involve any parts of this study.
The authors report no conflicts of interest.
Data sharing not applicable to this article as no datasets were generated or
analyzed during the current study.
a
Department of General Surgery, The First Hospital of Yulin, Yulin,
b
Department
of General Surgery, Yangling Demonstration District Hospital, Xianyang, Shaanxi,
China.
∗
Correspondence: Pu-guo Gui, Department of General Surgery, Yangling
Demonstration District Hospital, No.8 Houji Road, Yangling District, Xianyang
712100, China (e-mail: 120054381@qq.com).
Copyright ©2021 the Author(s). Published by Wolters Kluwer Health, Inc.
This is an open access article distributed under the Creative Commons
Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
How to cite this article: Hou Hp, Gui Pg. Effect of sigmoidectomy in treating
sigmoid colon cancer: a protocol of systematic review. Medicine 2021;100:3
(e23914).
Received: 26 November 2020 / Accepted: 30 November 2020
http://dx.doi.org/10.1097/MD.0000000000023914
Study Protocol Systematic Review Medicine®
OPEN
1

SCC. No limitations will be applied in terms of country, ethnicity,
and educational background.
2.3.3. Types of interventions. In the experimental group,
intervention to be utilized is sigmoidectomy alone.
In the control group, any treatment management could be
used, such as radiotherapy, chemotherapy, but not sigmoidec-
tomy.
2.3.4. Type of outcome measurements. Outcomes include
overall survival, pathological complete response, progression-
free survival, recurrence-free survival, and any complication.
2.4. Search methods for the identification of studies
2.4.1. Electronic databases search. We will search the
following databases from inception to the present: MEDLINE,
EMBASE, Cochrane Library, CINAHL, PsycINFO, Scopus,
OpenGrey, Chinese Biomedical Literature Database, and China
National Knowledge Infrastructure. No language and publica-
tion status limitations will be imposed to all above electronic
databases. We will build a detailed search strategy for Cochrane
Library in Table 1. In addition, we will also adapt similar search
strategies to any other electronic databases.
2.4.2. Search for other resources. Aside from above electronic
databases, we will also search conference proceedings, disserta-
tions, and reference list of associated reviews.
2.5. Data collection and analysis
2.5.1. Study selection. All searched records will be imported to
the Endnote X7 and all duplicated data will be eliminated. Then,
all titles and abstracts will be screened. After that, we will read
full text of all potential papers to determine if they fit the final
inclusion criteria. Any inconsistencies between 2 researchers will
be worked out by a third researcher through discussion. We will
note any exclusion reasons for all removed studies. The whole
process of study selection will be demonstrated in a flow diagram.
2.5.2. Data extraction and management. Two researchers will
independently extract all relevant data from included studies
using a standardized data extraction sheet. Any deviations
between 2 researchers will be coped with a third researcher
through consultation. The extracted information consist of study
title, first author, country, time of publication, characteristics of
patients, study setting, randomization, binding, allocation,
concealment, sample size, details of interventions, controls,
follow-up, outcome indicators, study results, adverse events, and
funding information. If we identify any missing or unclear data,
we will contact primary author to request them by email.
2.5.3. Risk of bias assessment. Two researchers will indepen-
dently appraise the risk of bias assessment for each qualified
study using Cochrane risk of bias tool based on the guidelines of
Cochrane Handbook for Systematic Reviews of Interventions. It
covers 7 aspects, and each item is further referred as low, unclear,
or high risk of bias. Any different opinions between 2 researchers
will be disentangled by a third researcher through discussion.
2.5.4. Measurement of treatment effect. For enumeration
data, we will employ the results as risk ratio and 95% confidence
intervals (95% CIs). For continuous data, we will exert the results
as mean difference or standardized mean difference and 95% CIs.
2.5.5. Assessment of heterogeneity. The heterogeneity of the
study results will be determined through I
2
test. I
2
50%
suggests low level of heterogeneity, and a fixed-effects model will
be utilized. I
2
>50% reveals a high level of heterogeneity, and a
random-effects model will be applied.
2.5.6. Data synthesis. RevMan 5.3 software will be employed
for statistical analysis in this study. Meta-analysis will be
undertaken if we identified low level of heterogeneity, and
sufficient data are collected on the similar characteristics of study
and patient, treatments, controls, and outcome records. Other-
wise, if high level of heterogeneity is found, we will perform
subgroup analysis to detect the possible reasons for such
situation. Moreover, we will carry out narrative summary for
the study results by reporting detailed written commentary to
present the target patient characteristics, study findings, types of
treatments and controls, and outcomes.
2.5.7. Reporting bias. Funnel plot and Egger regression test will
be performed to explore any potential reporting bias if sufficient
studies are available (normally at least 10 qualified studies).
[26]
2.5.8. Subgroup analysis. We will implement subgroup analy-
sis according to the different characteristics of study or patient,
intervention, comparators, and outcomes.
2.5.9. Sensitivity analysis. We will preside over sensitivity
analysis to explore the robustness of outcome results by
excluding low-quality studies.
2.5.10. Grading the quality of evidence. We will exploit
Grading of Recommendations Assessment, Development and
Evaluation method to check the strength of evidence for included
study. Two researchers will independently manage all the
assessments, and any different views between both of them will
be solved by a third researcher through discussion.
3. Discussion
A variety of previous studies have reported that sigmoidectomy is
often utilized in treating SCC. However, its results are still
inconsistent. Thus, it is necessary and crucial to make sure
whether sigmoidectomy is a good option for the treatment of
patients with SCC. This study aims to systematically and
comprehensively investigate the efficacy and safety of sigmoi-
dectomy in treating SCC. The results of this study will provide
Table 1
Search strategy of Cochrane Library.
Number Search terms
1 MeSH descriptor: (sigmoid neoplasms) explode all trees
2 MeSH descriptor: (colonic neoplasms) explode all trees
3 ((neoplasm
∗
) or (cancer
∗
) or (tumor
∗
) or (colon
∗
) or (sigmoid
∗
)or
(colonic
∗
) or (intestinal
∗
) or (colorectal
∗
)):ti, ab, kw
4 Or 1-3
5 MeSH descriptor: (general surgery) explode all trees
6 ((surgery
∗
) or (operation
∗
) or (sigmoidectomy
∗
) or (resection
∗
)or
(laparoscopic
∗
) or (surgical procedure
∗
)):ti, ab, kw
7Or5–6
8 MeSH descriptor: (randomized controlled trials) explode all trees
9 ((random
∗
) or (randomly
∗
) or (allocation
∗
) or (placebo
∗
) or (blind
∗
)
or (control trial
∗
) or (clinical trials
∗
)):ti, ab, kw
10 Or 8–9
11 4 and 7 and 10
Hou and Gui Medicine (2021) 100:3 Medicine
2

helpful evidence for both clinical practice and future relevant
studies.
Author contributions
Conceptualization: Hua-ping Hou, Pu-guo Gui.
Data curation: Hua-ping Hou, Pu-guo Gui.
Formal analysis: Hua-ping Hou, Pu-guo Gui.
Methodology: Hua-ping Hou, Pu-guo Gui.
Resources: Hua-ping Hou.
Software: Hua-ping Hou.
Validation: Hua-ping Hou, Pu-guo Gui.
Visualization: Hua-ping Hou, Pu-guo Gui.
Writing –original draft: Hua-ping Hou, Pu-guo Gui.
Writing –review & editing: Hua-ping Hou, Pu-guo Gui.
Investigation: Pu-guo Gui.
Project administration: Pu-guo Gui.
Supervision: Pu-guo Gui.
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