The Role of Mechanical Bowel Preparation in Laparoscopic Right Hemicolectomy With Totally Intracorporeal Anastomosis for Colon Cancer: A Randomized Controlled Trial
Phase: NA
Conditions: Colon Cancer
Sponsor: University Medical Center Ho Chi Minh City (UMC)

 
 
 
 
 
 
Official Title: 
THE ROLE OF MECHANICAL BOWEL PREPARATION IN LAPAROSCOPIC 
RIGHT HEMICOLECTOMY WITH TOTALLY INTRACORPOREAL 
ANASTOMOSIS FOR COLON CANCER:  
A RANDOMIZED CONTROLLED TRIAL 
 
NCT Number: 
Not yet assigned 
 
Document Type: 
Study Protocol 
 
Document Date: 
September 1, 2025 
 
 
 
 
 

 
 
 
 
 
TABLE OF CONTENTS 
TABLE OF CONTENTS 
LIST OF ABBREVIATIONS 
LIST OF TABLES 
REFERENCES  
 

 
 
LIST OF ABBREVIATIONS 
 
 
Abbreviations 
English 
MBP 
Mechanical Bowel Preparation 
 
 
 
 
 
 

1 
 
 
 
INTRODUCTION 
Surgery remains the cornerstone in the management of colon cancer, with the 
role of minimally invasive approaches becoming increasingly prominent. Among 
these, laparoscopic right hemicolectomy with totally intracorporeal anastomosis has 
been demonstrated to be safe and effective, without increasing the risk of 
intraoperative events or anastomotic complications. Moreover, it facilitates earlier 
recovery of bowel function and reduces the length of hospital stay 1-4. Consequently, 
this technique has gradually become an inevitable trend worldwide, including in 
Vietnam. 
The role of mechanical bowel preparation (MBP) alone in colorectal surgery 
remains controversial and has not been clearly established. Theoretically, MBP is 
intended to reduce intraluminal bowel contents, thereby decreasing the risk of 
surgical site infection and anastomotic complications. However, previous 
randomized controlled trials have failed to confirm these benefits5-8. Notably, these 
studies were conducted in patients undergoing extracorporeal anastomosis (via 
laparoscopic-assisted or open surgery), where the anastomosis can be directly 
controlled manually, thus significantly reducing the risk of fecal contamination of the 
operative field and peritoneal cavity. 
In the current context, where totally intracorporeal anastomosis is increasingly 
adopted, MBP may play a role in reducing intraoperative fecal contamination within 
the abdominal cavity, lowering the risk of surgical site infection, and avoiding 
prolongation of anastomotic construction time and overall operative duration. 
Therefore, this study was conducted to address the following question: Does 
mechanical bowel preparation reduce intraoperative events, postoperative 
complications, and facilitate faster recovery in patients undergoing laparoscopic right 
hemicolectomy with totally intracorporeal anastomosis? 
 

2 
 
 
 
STUDY OBJECTIVES  
To compare early outcomes of laparoscopic right hemicolectomy for colon 
cancer with totally intracorporeal anastomosis, with or without mechanical 
bowel preparation (MBP) via: 
1. Comparing 
intraoperative 
adverse 
events 
(intra-abdominal 
fecal 
contamination), postoperative complications (anastomotic leak, postoperative 
ileus, surgical site infection, and medical complications such as fluid–
electrolyte imbalance), and 30-day postoperative mortality between patients 
with and without MBP.  
2. Comparing operative outcomes (anastomotic construction time and total 
operative time) and postoperative recovery (time to first flatus, time to first 
bowel movement, and length of postoperative hospital stay) between the two 
groups. 
 
 

3 
 
 
 
LITERATURE REVIEW 
1.1 Colon cancer 
1.1.1 Overview 
Colon cancer is one of the most common malignancies of the gastrointestinal 
tract. More than 90% of colon cancers originate from glandular epithelial cells of the 
colonic mucosa (adenocarcinoma). Other less common histological types include 
neuroendocrine tumors, squamous cell carcinoma, spindle cell carcinoma, and 
undifferentiated carcinoma. 
According to GLOBOCAN 2020 data, colorectal cancer ranks third in 
incidence and second in mortality worldwide 9. ]. In Vietnam, colorectal cancer ranks 
fourth in men and second in women in terms of both incidence and cancer-related 
mortality 10. Furthermore, a recent study has projected that by 2025, colorectal cancer 
will become the second most common cancer in Vietnam for both sexes combined 11. 
1.1.2 TNM staging of colon cancer 
Based on data obtained from imaging modalities, accurate disease staging is 
mandatory prior to making treatment decisions. Comprehensive staging should 
include assessment of the extent of primary tumor invasion, the presence of regional 
lymph node metastases, and distant metastases. 
For decades, the TNM classification system developed by the American Joint 
Committee on Cancer (AJCC) has been widely adopted and accepted worldwide for 
evaluating cancer progression in general, and colorectal cancer in particular. In this 
system, T (tumor) refers to the primary tumor, N (regional nodes) to regional lymph 
node involvement, and M (metastasis) to distant metastasis 12.  
Since its introduction, the TNM classification has become a universal 
language among clinicians globally and serves as a fundamental framework for 
prognostic assessment and the development of treatment strategies in oncology.. 

4 
 
 
 
Based on the TNM classification, the American Joint Committee on Cancer 
8th edition defines stages of colon cancer as follows: Stage I includes tumors invading 
the submucosa or muscularis propria (T1–T2) without regional lymph node 
metastasis (N0); Stage II includes tumors invading the subserosa, pericolic tissues not 
covered by peritoneum, or penetrating the visceral peritoneum (T3–T4) without 
regional lymph node metastasis (N0); Stage III includes tumors with regional lymph 
node involvement regardless of the depth of tumor invasion (N1 or higher); and Stage 
IV includes tumors with distant metastasis (M1) 12. Accurate staging plays a critical 
role in prognostic assessment. In general, more advanced disease stages are 
associated with poorer outcomes. 
T3-4a 
T2-3 
T1-2 
N1 / N1c 
N2a 
N2b 
M0 
M0 
M0 
IIIB 
T4a 
T3-4a 
T4b 
N2a 
N2b 
N1-2 
M0 
M0 
M0 
IIIC 
T bất kỳ 
N bất kỳ 
M1a 
IVA 
T bất kỳ 
N bất kỳ 
M1b 
IVB 
T bất kỳ 
N bất kỳ 
M1c 
IVC 
 
In addition to the core TNM components, supplementary prefixes may be 
applied depending on the timing and context of staging. These include: c (clinical 
assessment), based on clinical and imaging data obtained prior to treatment; p 
(pathological staging), based on histopathological findings following surgical 
resection; y (post-treatment or restaging), indicating assessment after neoadjuvant 
therapy (e.g., chemotherapy or radiotherapy); r (recurrence), used for staging 

5 
 
 
 
recurrent disease after a disease-free interval; and a (autopsy), based on findings from 
postmortem examination. 
1.2 Laparoscopic right hemicolectomy / extended right hemicolectomy 
with totally intracorporeal anastomosis 
1.2.1 Surgical techniques 
From a technical perspective, according to Marco Milone, intracorporeal 
colonic anastomosis offers several advantages 2. First, the tumor-bearing colon 
does not require extensive mobilization for exteriorization, but only sufficient 
mobilization to allow intracorporeal anastomosis. Second, performing the 
anastomosis intracorporeally reduces exposure of digestive contents to the 
surgical wound, thereby decreasing the risk of surgical site infection. Third, the 
formation of intra-abdominal adhesions may be minimized due to reduced 
manual manipulation of the peritoneal cavity. Fourth, the length of the 
extraction incision can be reduced by up to 50%, as it is used solely for 
specimen retrieval rather than anastomotic construction, thereby reducing 
postoperative pain and wound-related complications. Finally, intracorporeal 
anastomosis under direct laparoscopic visualization eliminates the risk of 
anastomotic torsion associated with the limited operative field in extracorporeal 
techniques. 
However, Milone also highlighted several challenges associated with 
intracorporeal anastomosis 2. First, adequate bowel preparation is required to 
minimize intra-abdominal fecal contamination. Second, surgeons must possess 
advanced laparoscopic skills to perform intracorporeal suturing. Third, 
prolonged anastomotic construction time may increase the risk of anastomotic-
related complications. Fourth, operative costs may increase, as intracorporeal 
overlap techniques often require more stapling devices compared with 

6 
 
 
 
functional end-to-end anastomosis. In our study, we identified an additional 
challenge: for small colonic lesions, manual palpation during extracorporeal 
anastomosis facilitates accurate localization and determination of safe resection 
margins. This is more difficult when operating laparoscopically and often 
necessitates intraoperative colonoscopy, thereby prolonging operative time. 
 
Regarding operative time, previous studies have reported conflicting results. 
Studies by Vignali1 and Achilli 13 demonstrated significantly longer operative 
times in the intracorporeal anastomosis group, whereas studies by Allaix 3, 
Widmar 14, và Malczak 4 found no significant difference. In our study, total 
operative time did not differ significantly between the two groups (145.9 ± 32.0 
minutes vs. 138.7 ± 43.2 minutes, p = 0.04), although anastomotic construction 
time was significantly longer in the intracorporeal group (33.6 ± 6.1 minutes 
vs. 24.4 ± 6.1 minutes, p < 0.001). Intracorporeal anastomosis requires less 
extensive colonic mobilization, thereby shortening the resection phase. This 
reduction may offset the longer anastomotic construction time, resulting in no 
overall difference in total operative duration. Furthermore, both operative and 
anastomotic times are highly dependent on surgeon experience. As these were 
among our initial cases of intracorporeal anastomosis, these times may decrease 
as the surgical team progresses along the learning curve. 
In terms of postoperative recovery, numerous studies have demonstrated that 
intracorporeal anastomosis is associated with faster recovery of bowel function 
and shorter hospital stay. A meta-analysis by Milone in 2018, including 1,862 
patients undergoing laparoscopic right hemicolectomy, showed that 
intracorporeal anastomosis significantly reduced time to first flatus, time to first 
bowel movement, and length of hospital stay compared with extracorporeal 

7 
 
 
 
anastomosis2. These findings have been consistently confirmed in randomized 
controlled trials by Vignali1, Allaix3, Widmar14, và Malczak4. Notably, Vignali 
et al. also reported a markedly lower rate of postoperative ileus in the 
intracorporeal group (3.3% vs. 23.3%) 1. This may be explained by reduced 
bowel 
manipulation 
and traction 
during 
intracorporeal 
procedures. 
Additionally, longer extraction incisions in extracorporeal anastomosis may 
increase postoperative pain, analgesic requirements, and consequently the risk 
of ileus due to reduced mobilization and opioid-related effects. 
Regarding long-term outcomes, with a median follow-up of 40.0 
months in our study, no significant differences were observed between the two 
groups in terms of distant metastasis or cancer-related mortality. These 
findings are consistent with previous studies. However, our study has several 
limitations inherent to its retrospective design, including potential selection 
bias and differences in baseline characteristics between groups. Furthermore, 
postoperative pain, incision length, and surgical costs were not evaluated. 
Future prospective randomized controlled trials with comprehensive outcome 
assessment are needed to more accurately evaluate the advantages and 
limitations of these two techniques. 
1.2.2 Current Evidence 
Worldwide, the earliest studies comparing intracorporeal and 
extracorporeal anastomosis in laparoscopic right hemicolectomy were 
conducted around 2009. Hellan et al. performed a prospective study comparing 
23 patients undergoing intracorporeal anastomosis with 57 patients undergoing 
extracorporeal anastomosis15. Initial results demonstrated no significant 
differences in early postoperative outcomes between the two groups. However, 

8 
 
 
 
intracorporeal anastomosis was associated with a shorter incision and a 
potential reduction in wound-related complications. 
Over the subsequent decade, numerous retrospective and prospective 
studies have compared early postoperative outcomes between these two 
techniques in laparoscopic right hemicolectomy, although results remain 
somewhat inconsistent. Some authors have reported that intracorporeal 
anastomosis reduces length of hospital stay and improves postoperative 
recovery1,3. 
Randomized controlled trials have also demonstrated several advantages 
of intracorporeal over extracorporeal anastomosis. Mari et al. reported 
significantly lower postoperative levels of inflammatory markers, including 
interleukin-6 and C-reactive protein, in patients undergoing intracorporeal 
anastomosis 16. Similarly, Vignali et al. demonstrated improved postoperative 
recovery in the intracorporeal group compared with the extracorporeal group 1. 
Studies by Allaix et al. 3 and Bollo et al. 17 further showed that intracorporeal 
anastomosis was associated with better recovery of gastrointestinal function, 
lower rates of postoperative ileus, and reduced postoperative pain. 
Recent meta-analyses and systematic reviews have consistently 
suggested that intracorporeal anastomosis offers superior postoperative 
recovery compared with extracorporeal techniques. Analyses by Wu et al. 
(2016) 
18 , Milone (2018) 
2, and Emile (2019)19 demonstrated that 
intracorporeal anastomosis is associated with improved postoperative recovery, 
lower rates of surgical site infection, and reduced incidence of incisional hernia. 
Furthermore, patients undergoing intracorporeal anastomosis tend to 
experience faster return to normal physiological function, less wound pain, 

9 
 
 
 
shorter incision length, and significantly reduced hospital stay compared with 
those undergoing extracorporeal anastomosis. 
In Vietnam, there remains a relative paucity of studies comparing 
intracorporeal and extracorporeal anastomosis in laparoscopic colectomy in 
general, and right hemicolectomy in particular. Le Huy Luu reported a review 
highlighting the advantages of intracorporeal anastomosis over extracorporeal 
techniques in laparoscopic colectomy for cancer, as well as the challenges in 
adopting this technique in Vietnam 20. Dao Van Cam (2019)21 conducted an 
initial study demonstrating that intracorporeal anastomosis in laparoscopic 
colectomy is safe and feasible; however, this study did not include a direct 
comparison with extracorporeal anastomosis. 
 

10 
 
 
 
STUDY SUBJECTS AND METHODS 
1.3 Study design 
A single-center randomized controlled trial. 
1.4 Study setting and duration 
The study was conducted from April 2025 to April 2028 at University Medical 
Center Ho Chi Minh City. 
1.5 Study population 
1.6 Target population 
Patients undergoing right hemicolectomy or extended right hemicolectomy for 
colon cancer with totally intracorporeal anastomosis. 
1.7 Study population 
Patients undergoing right hemicolectomy or extended right hemicolectomy for 
colon cancer with totally intracorporeal anastomosis at University Medical 
Center Ho Chi Minh City between April 1, 2025 and April 1, 2028. 
1.8 Eligibilitiy criteria 
1.8.1 Inclusion criteria 
- Patients aged ≥18 years. 
- Patients with colon cancer stage I–III according to the TNM classification. 
- Patients undergoing right hemicolectomy or extended right hemicolectomy for 
colon cancer with totally intracorporeal anastomosis at University Medical 
Center Ho Chi Minh City. 
- Postoperative histopathology confirming adenocarcinoma. 
1.8.2 Exclusion criteria 
- Patients undergoing emergency surgery. 

11 
 
 
 
- Patients with contraindications to mechanical bowel preparation (e.g., bowel 
obstruction, subobstruction, bowel perforation, or peritumoral abscess). 
- Patients with contraindications to laparoscopic surgery (American Society of 
Anesthesiologists (ASA) physical status IV or V) or contraindications to 
intracorporeal anastomosis (e.g., bowel obstruction, subobstruction, bowel 
perforation, or peritumoral abscess). 
- Patients with distant metastasis at the time of surgery (stage IV according to 
the TNM classification). 
- Patients with recurrent colon cancer after prior surgery. 
- Patients with synchronous primary malignancies in organs other than the colon. 
- Patients undergoing palliative surgery or surgery for tumor-related 
complications (non-curative intent). 
- Patients lost to follow-up or unable to be contacted. 
1.9 Sample size calculation 
All patients were allocated into two groups: 
- Group I: with mechanical bowel preparation (MBP) before surgery.  
- Group II: without mechanical bowel preparation before surgery.  
The sample size was determined based on the primary outcome of the study, which 
was the rate of anastomotic leakage. The sample size for comparing two proportions 
was calculated using the following formula: 
- 
 
Where: 
- n: minimum sample size required for each group.  
- α: type I error probability; with α = 0.05, 𝑍(1−𝛼/2) = 1.96.  

12 
 
 
 
- β: type II error probability; with β = 0.20, 𝑍(1−𝛽) = 0.84 
- p1: rate of surgical site infection in Group I, according to Ozawa et al.22, 
p1=0,045 
- p2: rate of surgical site infection in Group I, according to Ozawa et al.22, 
p2=0,313 
- p* = (p1 + p2)/2 = 0,18 
- Substituting these values into the formula yielded a required sample size of n 
≥ 32. 
- To account for potential dropout and loss to follow-up, an additional 15% of 
participants will be recruited. Therefore, the total sample size is increased from 
64 to 74 patients. 
1.10 Randomization, Allocation Concealment, and Blinding 
Participants were randomly assigned in a 1:1 ratio to either the mechanical bowel 
preparation (MBP) group or the no mechanical bowel preparation group. 
Randomization was performed using a centralized, web-based platform employing a 
minimization algorithm to ensure balance between groups with respect to age (≤60 
vs >60 years), sex, and tumor stage (stage II vs III). 
Allocation concealment was maintained through the web-based system, which 
generated group assignments only after patient enrollment. The allocation sequence 
was not accessible to the investigators involved in patient recruitment or surgical 
procedures. Group assignments were available exclusively to designated research 
personnel responsible for preoperative preparation. 
Blinding was implemented at the level of the operating surgeons (investigators). 
Due to the nature of the intervention, participants were aware of their assigned group. 
However, the surgeons performing the procedures were not informed of the allocation 
prior to surgery. Standardized perioperative management protocols were applied to 
all participants to minimize potential bias. 

13 
 
 
 
Complete blinding of the operating surgeons may not be fully guaranteed due to 
intraoperative 
findings; 
however, 
allocation 
concealment 
and 
protocol 
standardization were strictly maintained to reduce the risk of bias. Whenever feasible, 
postoperative outcomes were assessed using predefined objective criteria, and 
outcome assessors not involved in the surgical procedures were kept blinded to group 
allocation. 
 
 
1.11 Definition of variables 
- Age: Continuous variable, expressed in years, calculated at the time of surgery. 
- Sex: Binary variable (male/female). 
Patients meeting the study 
eligibility criteria
Provided informed consent to 
participate in the study
Stratification factors:
Age (<60 vs. ≥60 years) 
Sex (male/female) 
Cancer stage (II vs. III)
Minimization algorithm:
Calculation of imbalance 
Comparison between groups
Group A
Group B
Update 
system data

14 
 
 
 
- 
ASA score: Patient physical status classified according to the American 
Society of Anesthesiologists, ranging from I to IV 23. 
- Body mass index (BMI): Continuous variable (kg/m²), calculated as body 
weight (kg) divided by the square of height (m²), measured at the time of 
surgery. Classified according to WHO criteria for Asian populations. 
- Preoperative laboratory parameters: Hemoglobin, albumin, sodium, potassium, 
magnesium, phosphate, and bicarbonate levels measured within 3 days prior to 
surgery. 
- Postoperative laboratory parameters: Hemoglobin, albumin, procalcitonin, 
sodium, potassium, magnesium, phosphate, and bicarbonate levels measured 
after surgery. 
- Comorbidities: Categorical variable, including hypertension, diabetes mellitus, 
cardiovascular diseases (atrial fibrillation, coronary stent, prior myocardial 
infarction, chronic ischemic heart disease), chronic obstructive pulmonary 
disease, bronchial asthma, cirrhosis, chronic kidney disease, and Cushing 
syndrome. 
- Tumor 
location: 
Categorical 
variable 
determined 
by 
preoperative 
abdominopelvic computed tomography (CT), including cecum, ascending 
colon, hepatic flexure, and transverse colon. 
- Tumor size: Continuous variable (cm), defined as the largest dimension 
(length, width, or height) measured on preoperative CT imaging. 
- Tumor differentiation: Histopathological grading (well, moderately, or poorly 
differentiated). 
- Cancer stage: TNM staging according to the American Joint Committee on 
Cancer 8th edition12, dựa vào hình chụp cắt lớp vi tính bụng chậu trước phẫu 
thuật. 
- Preoperative fasting time (solid food): Continuous variable (hours), calculated 
from the last intake of solid food before surgery to the start of surgery. 

15 
 
 
 
- Preoperative fasting time (liquids): Continuous variable (hours), calculated 
from the last intake of liquids before surgery to the start of surgery. 
- Operative time: Continuous variable (minutes), measured from skin incision to 
completion of skin closure, as recorded in the operative report and medical 
records. 
- Anastomotic construction time: Continuous variable (minutes), measured from 
completion of bowel resection to completion of the anastomosis, as recorded 
in the operative report. 
- Degree of fecal contamination: Categorical variable, classified as distant from 
the anastomosis / at the anastomosis / none. 
- Bowel condition: Categorical variable, classified as solid stool / liquid stool / 
clean bowel. 
- Intraoperative blood loss: Continuous variable (mL), recorded in the operative 
report. 
- Intraoperative adverse events: Categorical variable, including organ injury 
(organs other than the colon) and intra-abdominal fecal contamination, as 
recorded in the operative report. Intra-abdominal fecal contamination is defined 
as gross spillage of intestinal contents into the peritoneal cavity beyond the 
bowel mucosa, confirmed and documented by the operating surgeon. 
- Postoperative complications (Clavien–Dindo classification): Postoperative 
complications were graded according to the Clavien–Dindo classification 
system, ranging from Grade I to Grade V 24. 
- -Surgical site infection (SSI): Categorical variable. In this study, the term 
surgical site infection includes superficial SSI, deep SSI, and organ/space SSI, 
as defined by the Centers for Disease Control and Prevention.25. All cases of 
infection involving the skin and subcutaneous tissue occurring within 30 days 
after surgery, with at least one of the following findings: purulent discharge 
from the incision, positive wound culture, wound opening or drainage requiring 
suture removal or packing, together with signs of inflammation (swelling, 

16 
 
 
 
warmth, redness, pain), or a diagnosis of superficial surgical site infection by 
the surgeon, were classified as superficial SSI. 
- All cases of infection involving the fascial and muscle layers of the incision 
occurring within 30–90 days after surgery, with at least one of the following 
findings: purulent discharge, positive wound culture, wound opening or 
drainage, or spontaneous wound dehiscence, together with symptoms such as 
localized tenderness or fever >38°C, or a diagnosis of deep SSI by the surgeon, 
were classified as deep SSI. 
- All cases of infection involving organs or body spaces occurring within 30–90 
days after surgery, with at least one of the following findings: purulent drainage 
from a drain placed in the organ/space, positive culture from drainage fluid, or 
evidence of abscess or infection on clinical examination, histopathology, or 
imaging, and meeting the diagnostic criteria for intra-abdominal infection, 
were classified as organ/space SSI. 
- According to Centers for Disease Control and Prevention criteria, intra-
abdominal infection was diagnosed if at least one of the following was present: 
(1) evidence of abscess or infection on clinical or histopathological 
examination; (2) positive culture from intra-abdominal fluid or drainage; or (3) 
at least two of the following clinical features: fever >38°C, hypotension, 
nausea, vomiting, abdominal pain, elevated liver enzymes (transaminases), or 
jaundice, together with at least one of the following: Gram stain demonstrating 
bacteria in intra-abdominal fluid/drainage, or imaging findings consistent with 
intra-abdominal infection. 
- Wound dehiscence: Categorical variable, defined as separation of the 
abdominal fascia at the incision site, with or without evisceration.  
- Bleeding (wound/intra-abdominal/gastrointestinal): Categorical variable, 
defined as bleeding from the surgical wound, abdominal cavity, or 
gastrointestinal tract requiring procedural or surgical intervention (e.g., 
hemostatic suturing or reoperation).  

17 
 
 
 
- Postoperative electrolyte imbalance: Categorical variable, defined as the 
presence of any of the following abnormalities: hypokalemia (serum potassium 
≤3.5 mmol/L), hyperkalemia (≥5.5 mmol/L), hyponatremia (serum sodium 
≤130 mmol/L), hypernatremia (≥150 mmol/L), hypomagnesemia (≤0.50 
mmol/L), hypophosphatemia (≤0.80 mmol/L), metabolic acidosis (serum 
bicarbonate ≤22 mmol/L), or metabolic alkalosis (≥30 mmol/L). 
- 
26. 
- Length of postoperative hospital stay: Continuous variable (days), calculated 
from the date of surgery (postoperative day 0) to discharge. 
- Time to first flatus: Continuous variable (days), calculated from the date of 
surgery to the first passage of flatus. 
- Time to first bowel movement: Continuous variable (days), calculated from the 
date of surgery to the first defecation. 
- 30-day postoperative mortality: Proportion of patients who died from any cause 
within 30 days after surgery. 
1.12 Study procedure 
All patients diagnosed with colon cancer at University Medical Center Ho Chi 
Minh City who, after multidisciplinary team discussion, were indicated for right 
hemicolectomy or extended right hemicolectomy and met the study inclusion criteria 
were approached by a member of the research team. Patients were provided with 
detailed information regarding the surgical procedure and study participation. 
If the patient agreed to participate, written informed consent for both the surgical 
procedure and study participation was obtained from the patient and their legal 
representative. Patients were then randomly assigned by a member of the research 
team, using a lottery method, to one of two groups: with or without mechanical bowel 
preparation (MBP) prior to surgery. 

18 
 
 
 
1.13 Preoperative investigastions 
All patients included in the study underwent laboratory testing, including complete 
blood count, serum albumin, procalcitonin, creatinine, and serum electrolytes 
(sodium, potassium, magnesium, phosphate, and bicarbonate). These investigations 
were performed within 3 days prior to surgery. 
1.13.1 Mechanical bowel preparation 
On the day before surgery, all patients were allowed solid food until 22:00 and 
fasted thereafter until surgery. On the day of surgery, patients were allowed to drink 
water ad libitum and received 400 mL of 12.5% maltodextrin solution every 4 hours 
until 2 hours before surgery. 
On the evening prior to surgery, patients in the mechanical bowel preparation 
(MBP) group received 3 liters of water mixed with three sachets of Coliet (Medisun 
Pharmaceutical Joint Stock Company; each sachet containing macrogol 4000 64 g, 
sodium bicarbonate 1.68 g, sodium sulfate 5.7 g, sodium chloride 1.46 g, potassium 
chloride 0.75 g, and sodium saccharin as excipient) for bowel preparation. The MBP 
protocol was approved and implemented at University Medical Center Ho Chi Minh 
City. 
1.13.2 Laparoscopic right hemicolectomy with totally intracorporeal 
anastomosis 
All procedures were performed by members of the research team. 
a). Patient positioning and trocar placement 
Patients underwent general anesthesia with endotracheal intubation and were 
placed in the supine position, with arms and legs adducted, in a 20–30° Trendelenburg 
position and 20–30° left tilt. Five trocars were inserted as follows: a 10-mm port at 
the umbilicus, a 12-mm port in the left subcostal region, and three 5-mm ports in the 
left flank, right iliac fossa, and right flank. 

19 
 
 
 
b). Colonic mobilization 
The surgeon explored the abdominal cavity to assess tumor characteristics, 
including the extent of tumor invasion, regional lymph node involvement, evidence 
of distant metastasis, and tumor-related complications. The terminal ileum, appendix, 
and cecum were mobilized from the posterior abdominal wall. The right ureter and 
gonadal vessels were identified and preserved. The ascending colon and right 
mesocolon were further mobilized from the posterior abdominal wall, as well as from 
the duodenum and pancreatic head. 
The greater omentum was divided to mobilize the transverse colon from the greater 
curvature of the stomach. The transverse colon, hepatic flexure, and corresponding 
mesocolon were mobilized from the posterior gastric wall, duodenal frame, and 
abdominal wall. 
c). Vascular ligation 
The ileocolic vessels and right colic vessels (if present) were ligated at their origin, 
with lymphadenectomy performed at the root of the ileocolic artery. Complete 
mesocolic excision (CME) was carried out. 
For tumors of the cecum and ascending colon, the right branch of the middle colic 
vessels was ligated, and lymphadenectomy was performed at the origin of the middle 
colic trunk. For tumors of the hepatic flexure and transverse colon, the middle colic 
vessels were ligated at their origin, with lymphadenectomy performed at the root of 
the middle colic artery. 
d). Bowel resection 
The terminal ileum was transected approximately 20 cm proximal to the ileocecal 
valve, and the transverse colon was transected at least 10 cm distal to the tumor using 
an endoscopic linear stapler. The resected ileocolic specimen was placed in a 
specimen retrieval bag. Hemostasis was carefully ensured, and the operative field was 
irrigated with 0.9% saline solution. 

20 
 
 
 
e). Intracorporeal anastomosis, mesenteric closure, and abdominal drainage 
The terminal ileum and transverse colon were positioned side by side in an 
isoperistaltic orientation. Small enterotomies (5–10 mm in diameter) were created on 
the antimesenteric borders of both the ileum and transverse colon using monopolar 
electrocautery. A side-to-side ileocolic anastomosis was constructed using an 
endoscopic linear stapler. The common enterotomy was closed with a continuous 
suture using polydioxanone (PDS) 3-0 or 4-0, followed by reinforcement with 
interrupted PDS 3-0 or 4-0 sutures. 
The mesenteric defect at the ileocolic anastomosis was closed with a continuous 
PDS 3-0 or 4-0 suture. A 16-Fr drain was placed in the right paracolic gutter and 
exteriorized through the right flank. 
f). Specimen extraction 
The colonic specimen was extracted within a retrieval bag through a suprapubic 
transverse incision measuring 5–10 cm. The peritoneum at the incision site was 
closed with continuous polyglactin 3-0 sutures. The rectus muscle was approximated 
with interrupted polyglactin 3-0 sutures. The anterior rectus sheath at the suprapubic 
incision was closed with continuous polyglactin 1 sutures. Fascial defects at the 10-
mm and 12-mm trocar sites were closed with polyglactin 1 sutures. 
The suprapubic incision was irrigated with 100 mL of 0.9% saline solution. The 
skin was closed with interrupted nylon 3-0 sutures 
 

21 
 
 
 
Figure 1. Study protocol 
 
 
 
 
 
 
 
 
 
 
2025–2027 
Patients with colon cancer at University Medical Center Ho Chi Minh City who 
met the inclusion criteria and provided informed consent were enrolled 
Randomization 
MBP 
Non MBP 
Laparoscopic right 
hemicolectomy / extended right 
hemicolectomy with totally 
intracorporeal anastomosis 
 
Evaluate 
Laparoscopic right 
hemicolectomy / extended 
right hemicolectomy with 
totally intracorporeal 
anastomosis 
Evaluate 

22 
 
 
 
1.14 Postoperative care and assessment 
Patients were allowed oral intake of water and a liquid diet within 24 hours after 
surgery, provided there were no contraindications (e.g., postoperative ileus, bowel 
obstruction, or persistent vomiting). 
Routine laboratory tests, including complete blood count, serum albumin, 
procalcitonin, creatinine, and electrolytes, as well as abdominal ultrasound, were 
performed on postoperative day 2 and repeated every 48 hours. 
Wound dressings were changed every 24 hours starting from postoperative day 2. 
Samples of suprapubic wound discharge and drain fluid were collected for culture on 
postoperative day 3. 
1.15 Data analysis 
All data were collected, processed, and analyzed using Microsoft Excel and SPSS 
software. Continuous variables were compared using the Student’s t-test when 
normally distributed and the Mann–Whitney U test when non-normally distributed. 
Categorical variables were analyzed using the chi-square test or Fisher’s exact test, 
as appropriate. 
Logistic regression analysis was performed to identify independent risk factors. A 
p-value of <0.05 was considered statistically significant. 
1.16 Ethical considerations 
This study was approved by the Institutional Review Board of University of 
Medicine and Pharmacy at Ho Chi Minh City. 
Participants had the right to withdraw from the study at any time without any 
impact on their medical care. All patient information was kept strictly confidential in 
accordance with regulations of the Ministry of Health

23 
 
 
 
EXPECTED RESULTS 
Objective 1: To compare intraoperative adverse events (intra-abdominal fecal 
contamination), postoperative complications (anastomotic leak, postoperative ileus, 
deep surgical site infection, superficial surgical site infection, and medical 
complications), and 30-day postoperative mortality between patients with and 
without mechanical bowel preparation (MBP). 
Objective 2: To compare operative outcomes (anastomotic construction time 
and total operative time) and postoperative recovery (time to first flatus, time to first 
bowel movement, and length of postoperative hospital stay) between patients with 
and without MBP. 
The expected results will be presented in tables and figures as follows: 
Table 3.1: Baseline clinical and laboratory characteristics of patients 
Patient characteristics 
n or Mean ± SD 
Percentage 
(%) 
Age 
 
 
Sex 
 
 
BMI 
 
 
ASA score 
 
 
Comorbidities: 
• Cardiovascular disease 
• Diabetes mellitus 
• Respiratory disease (COPD, asthma) 
• Cirrhosis 
• Chronic kidney disease 
• Cushing syndrome 
 
 
Pre-operative 
hemoglobin, 
albumin, 
sodium, potassium, magnesium, phosphate, 
and bicarbonate levels 
 
 

24 
 
 
 
Post-operative 
hemoglobin, 
albumin, 
sodium, potassium, magnesium, phosphate, 
and bicarbonate levels 
 
 
Tumor location 
• 
Cecum  
• 
Ascending colon  
• 
Hepatic flexure  
• 
Transverse colon 
 
 
Maximum tumor size (mm) 
 
 
Tumor differentiation 
 
 
 
Table 3.2: Surgical outcomes 
Surgical outcomes 
 
Preoperative fasting time for solid food (hours) 
 
Preoperative fasting time for liquid food (hours) 
 
Operating time (minutes) 
 
Anastomotic construction time (minutes) 
 
Intraoperative blood loss (mL) 
 
Intraoperative adverse events 
• 
Organ injury  
• 
Intra-abdominal fecal contamination 
 
Time to first flatus (days) 
 
Time to first bowel movement (days) 
 
Length of postoperative hospital stay (days) 
 
Postoperative complications 
• 
Superficial surgical site infection  
 

25 
 
 
 
• 
Deep surgical site infection  
• 
Organ/space surgical site infection  
• 
Anastomotic leak  
• 
Intra-abdominal bleeding  
• 
Gastrointestinal bleeding  
• 
Gastrointestinal fistula  
• 
Abdominal wound dehiscence  
• 
Fluid–electrolyte imbalance  
• 
… 
Clavien–Dindo classification of postoperative complications 
 
30-day postoperative mortality rate 
 
 
 

 
 
 
 
 
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