Nghiên cứu sự thay đổi hàm lượng malondialdehyde ở bệnh nhân ung thư đại tràng trước và sau phẫu thuật triệt căn tt tiếng anh

MINISTRY OF EDUCATION
TRAINING

MINISTRY OF AND
DEFENSE

VIETNAM MILITARY MEDICAL UNIVERSITY
========

PHAM MANH CUONG

RESEARCH ON CHANGES OF MALONDIALDEHYDE
CONTENT IN PATIENTS WITH COLON CANCER
BEFORE AND AFTER RADICAL SURGERY

Major : Gastrointestinal surgery
Code

: 9 72 01 04

SUMMARY OF MEDICAL DOCTORAL THESIS

HANOI - 2019


WORKS COMPLETED AT
VIETNAM MILITARY MEDICAL UNIVERSITY

Supervisor:
1. Ass. Prof. Nguyen Van Xuyen
2. Ass. Prof. Trinh Hong Thai

Reviewer 1: Ass. Prof. Nguyen Xuan Hung
Reviewer 2: Prof. Ha Van Quyet
Reviewer 3: Ass. Prof. Nguyen Anh Tuan

The thesis will be defended in front of the Reviewing Council at
the University level at:
Time….. day…..month….year…

The thesis can be found out at:
1. National Library
2. Library of Vietnam Military Medical University


LIST OF PUBLISHED RESEARCH WORKS BY THE
AUTHOR RELATED TO THE THESIS
1. Pham Manh Cuong, Nguyen Van Xuyen (2018). Understanding
factors related to length of the colon section removed after
radical surgery for colon cancer treatment at Military Hospital
103. Journal of Military Pharmaco - Medicine, 43 (special
subject of abdominal surgery): 44-50.
2. Pham Manh Cuong, Nguyen Van Xuyen, Trinh Hong Thai
(2019).

Investigation

on

changes

in

the

erythrocyte

Malondialdehyde value in patients with colon cancer after
radical surgery. Journal of military pharmaco - medicine, 44(2):
213-219.
3. Pham Manh Cuong, Nguyen Van Xuyen, Trinh Hong Thai
(2019). The comparison of oxidative stress between tumour
tissue and healthy colon tissue using the Malondialdehyde index
in colon cancer patients undergoing radical surgery at 103
Military Hospital. VietNam Medical Journal, 481(1): 71-75.


1
BACKGROUND
Currently, the strong development of researches on the
mechanism of action and consequences of free radicals, as well as
oxidative stress on the body has provided evidence showing that
oxidative stress and Oxygen-free radicals are also a pathological
factor involved in the development of colon cancer.
In particular, the results of many studies show that oxidative
stress and the presence of oxygen-free radicals, produced during
surgery removing colon cancer, also play an important role in relapse
and metastasis after surgery. Therefore, the study of changes in
oxidative stress after surgery is currently of interest to many
researchers. There are many indices to assess oxidative stress status,
but in the studies, the most widely and commonly applied index to

indirectly assess oxidative stress in general and in abdominal surgery
in particular is Malondialdehyde (MDA), a product of lipid
peroxidation.
In Vietnam, not many studies mentioned the issue of oxidative
stress in colon cancer and exploring the changes in MDA content
after radical surgery for colon cancer treatment. Therefore, we
conducted the topic “Research on the changes in Malondialdehyde
content in patients with colon cancer before and after radical
surgery” with the following goals:
1. Study the Malondialdehyde content in patients with colon
cancer who underwent radical surgery treatment.
2. Evaluate the changes in red blood cell Malondialdehyde
content of patients with colon cancer after radical surgery.
Layout of the thesis
The thesis consists of 124 pages, including the following parts:


2
Background (2 pages), Overview (38 pages), Subjects and research
methodology (20 pages), Results (32 pages), Discussion (30 pages),
Conclusion (2 pages). The thesis has 56 tables, 11 figures, 11 charts,
1 diagram, 173 references including 11 Vietnamese documents, 162
English documents, and 53 documents within 5 years.
CHAPTER 1
OVERVIEW
1.1. Colon cancer and radical surgery to treat colon
cancer
Radical surgery is the main method in colon cancer treatment,
chemicals and radiation therapy are complementary method to
surgery. Currently, there has not yet been a specific and consensus

standard to precisely determine the radical surgery for colon cancer;
however, to ensure the treatment in cancer surgery, radical surgery is
required to comply with the following requirements.
* Diagnosis of the disease stage before surgery
Examining the entire colon (with one or more tumors, polyps
combined), diagnosing the disease stages (with lymph node
metastases, distant metastases), assessing the local invasion of the
tumor before surgery exactly are essential to plan the radical surgery
for colon cancer.
* Vertical colon resection extent
For colon cancer, a length of 5cm is defined as no more cancer
organization and will not cause recurrence at the junction. In surgery,
the actual length of the colon segment removed will be determined by
the removal extent of the colon arteries, parallel to the lymphatic
drainage. This length may have to be extended, depending on the
extent of lymph node dredging.


3
* Resection extent of invaded organs
During surgery, it is difficult to identify if an organ or organization
that is attached to the tumor is due to inflammation or invasive colon
cancer. Therefore, when the tumor invades a nearby organ, in surgery it
should be removed the tumor together with the invaded organ in an
integral block (en bloc resection).
* Extent of lymph node dredging
At the time of surgery, according to many studies up to 50% of
colon cancer possibly has regional lymph node metastases, so the
lymph node dredging is an indispensable part and lymph node
dredging must be done thoroughly.

1.2. Oxidative stress and the role of oxidative
stress in colon cancer
In the body, free radicals are frequently created, due to containing
oxygen, they are also called reactive oxygen species (ROS), and they
are always in balance with the body's antioxidant system. Oxidative
stress is the state where the formation of ROS is beyond the control of
the antioxidant system, the result is that ROS will attack biological
molecules such as: Lipids (lipid peroxidation), Protein ( protein
oxidation), Nucleic acid (DNA oxidation) leading to changes in
biological molecules, producing a number of toxic products that
damage cells, tissues and result in abnormal activities of the body. In
addition, through ROS, oxidative stress also affects cell signaling
pathways, causing false information leading to abnormal development
of cells such as uncontrolled cancer cell proliferation.
Similar to the respiratory tract, the intestinal tract are the organ
that most exposed to the environment through the food digestion
process. In particular, the bacteria are concentrated much in the colon


4
and very little in the small intestine, so the colon mucosa cells are
constantly exposed to chemicals, free radicals. Studies also show that
increased intestinal oxidation is associated with risk factors for colon
cancer such as chronic ulcerative colitis, obesity, lack of physical
exercise, and a diet high in red meat, smoking and alcohol abuse.
Studies on molecular biology show that oxidative stress may affect
mutations of the genes K-Ras, p53, APC or MMR (DNA mismatch
repair gene), these genes play an important role in leading to colon
cancer. In addition, clinical studies also indicate that the level of
oxidative stress is related to the factors expressing the progression of

cancer, such as lymph node metastasis, venous invasion, disease stage...
1.3. Role of oxidative stress in recurrence of colon
cancer after surgery
There are many factors that affect the recurrence of colon cancer
after surgery have been identified such as: biological characteristics
and histopathology of tumors, postoperative chemical treatment,
surgical techniques, in which the stage of the disease is the most
important factor determining the postoperative survival rate and also
the factor the most affecting the recurrence rate after surgery.
Currently, there are many evidences showing that surgery process
itself also contributes to postoperative outcomes of cancer treatment.
Surgery, even though it works for therapeutic purposes, is still a
traumatic impact on the body and is also an exogenous cause
producing many free radicals and oxidative stress because trauma in
surgery causes the body's “stress”, which is called surgical stress,
leads to an increase in free radicals through activating ROSproducing enzymes such as XO (xanthine oxidase), Cox
(Cyclooxygenase) and especially NADPH oxidase (nicotinamide


5
adenine dinucleotide phosphate-oxidase) or also called Nox.
Abdominal surgery also increases free radicals and oxidative stress
through the mechanism of ischemia-reperfusion injury due to the
effect of increasing the abdominal pressure in laparoscopic surgery,
exposure to operating room air in open surgery and mechanical
operations on the intestine.
Recent studies have also demonstrated that free radicals
containing active oxygen species (ROS) and redox signaling appear
when surgery plays a role in promoting invasive and metastatic
growth of mass tumor cells left after surgery to treat colon cancer.

The process of cancer cells left after surgery develops into metastases
in the new organ, the following phenomena are required: invasive
cancer cells (Invadopodia formation), escape from the capillaries to
adhere to new tissues, new organs (Adhesion), Angiogenesis, and
uncontrolled proliferation cells. ROS generated during the surgery
play a role of motivating, facilitating these phenomena to occur.
1.4. Biological indicators (biomarkers) to assess
oxidative stress in surgery
There are many methods to assess the body's oxidative stress.
The direct method is to quantify ROS and the indirect method is to
assess through measurement of stable metabolites of ROS or products
of ROS process interacting with biological molecules such as lipids,
proteins, DNA. In the body, ROS exists in a very short time and their
concentration is very low. To determine ROS, it requires modern and
expensive techniques and equipment, so clinical studies often use
indirect methods to assess oxidative stress.
The oxidation of biological molecules produces a wide range of
products that can be used as biological indicators to assess oxidative


6
stress such as: Carbonyl proteins (Product of protein oxidation
process), 8-OHdG (Product of DNA oxidation process)... However,
the product which is used the most in studies to assess oxidative stress
in general and in abdominal surgery in particular is Malondialdehy
(MDA) of lipid peroxidation. According to Pappas-Gogos G. (2013),
the lipids of cell membranes are the molecules involved the earliest in
reacting with free radicals, while oxidation of proteins and DNA
occurs at a later time.
In addition, MDA is the most commonly used in many studies

because it is easily quantified by quantification of MDA derivatives
with TBA (Thiobacbituric Acid), and this quantification of
derivatives can use a very simple, low cost, convenient spectroscopic
method, which can be done on many different biological samples.
1.5. Studies on Malondialdehyde in colon cancer patients in the
world and in Vietnam
MDA, an index commonly used to assess oxidative stress, has
also been used in many studies to evaluate on colon cancer patients.
MDA was quantified in serum, plasma, red blood cells, urine and colon
tissue to make comparisons between the two groups: 1 group is colon
cancer patients,

1 reference group is healthy persons, as well as

explore the relationship between MDA index and pathological factors
in colon cancer.
The changes in oxidative stress have been studied after surgery for
lung cancer, breast cancer and also studied after surgery for colon cancer.
All studies have shown that oxidative stress occurs right after surgery for
colon cancer and tends to decrease over time after surgery, however, there
is a difference among studies in time and evaluation index.


7
Studies have also explored the role of laparoscopic surgery, of
breathing with high oxygen levels or blood transfusion in surgery to
oxidative stress in surgery, but the effect of surgery duration or the
relationship between postoperative oxidative stress and surgical
outcomes has not been mentioned in any study.
In Vietnam, there have been no studies finding out about MDA

content before surgery and the change of MDA after radical surgery
to treat colon cancer.
CHAPTER 2
SUBJECTS AND RESEARCH METHODOLOGY
2.1. Research subjects
A total of 74 patients who were diagnosed with colon cancer,
underwent inpatient treatment at the Department of Abdominal
Surgery - Military Hospital 103 and was carried out radical surgical
treatment from March 2015 to January 2017 (serve for target 1). Of
which, 60 patients had enough test results of red blood cell MDA
index at 4 times before and after radical surgery (serve for target 2).
2.1.1. Selection criteria
- Criteria for identifying colon tumors: Applying the International
Classification of Diseases for Oncology, 3rd Edition of the World
Health Organization, the position of the tumor in the colon cancer
determined from cecum to the end of the sigma colon, above the
rectosigmoid junction. In this study, the tumor was identified as of the
colon, with the tumor position 15cm away from the anal margin.
- Colon cancer patients at stages I, II and III. The anatomical
result on the tumor cell morphology is adenocarcinoma.
- Carry out radical surgery to remove the tumor in the colon, with a
surgery minutes describing in details the lesions and techniques.


8
- Follow the procedure of treatment, nursing before, during and
after surgery, have complete medical records and voluntarily agree to
give disease samples for research.
2.1.2. Exclusion criteria
- Recurrent colon cancer or secondary colon due to that cancer

from
other organs metastasize.
- Colon cancer has been treated with chemicals and radiation
therapy before surgery.
- Colon cancer must undergo emergency surgery.
- Colon cancer associated with other diseases combined (diabetes,
cardiovascular disease, systemic disease …), smoking history, BMI >30.
2.2. Research methodology
2.2.1. Research design
Prospective study, no-control cross sectional description, with
before-after comparison.
2.2.2. Sample size:
With the main objective of comparing MDA content between tumor
tissue with normal colon tissue and investigating the change of peripheral
erythrocyte MDA before and after the surgery, we applied the formula to
calculate the minimum sample size following Miot H. A. (2011).

Of which n: sample size, Zα/2: value of error α, Zβ: value of
error β, in this research (Z α/2 + Zß)² = 10.5 with α is 0.05, ß is 0.1.
Sa and Sb: standard deviation of the variable in each group, d:
minimum difference between the mean values. Referring to research
of Upadhya S. and CS (2004) (a study comparing erythrocyte MDA


9
content between colorectal cancer groups and healthy people), with
Sa = 3.4, Sb = 5,9; d = 2,9 (8,3-5,4). Replace the above formula: n =
57.89. Therefore, the minimum expected sample size is 58 patients.
2.2.4. Method to determine MDA content
2.2.4.1. Principle of the MDA quantitative method

The principle of the method is based on the chemical reaction of
MDA molecule with thiobarbituric acid (TBA) (also called TBA test
method). MDA reacts with TBA in proportion 1:2 to create MDA(TBA)2 complex which has a characteristic pink color, the reaction
takes place at temperature 98oC, appropriate pH from 2-3. The MDA(TBA)2 complex was measured at a maximum absorption wavelength
of 535 nm using a spectrophotometer. From this absorbance value, the
corresponding MDA amount in the reaction solution will be
determined, thereby quantifying the MDA content in the sample.
2.2.4.2. Measurement of MDA for tissue samples
Tissue samples of patients with colon cancer for MDA index
determination are provided by the Department of Anatomic
Pathology, Military Hospital 103. The colon segment containing the
tumor after being removed from the patient via surgery will be cold
stored in an ice box (without formalin) and taken to the Department
of Anatomic Pathology. Here, tissue samples are taken at two
locations: diseased tissue is taken at the tumor and normal tissue is
taken at a location at least 5cm from the tumor edge. The tissue
samples were then stored at minus 1960C with liquid nitrogen before
being taken to oxidative stress testing. The method of quantifying
MDA on tissue samples was carried out based on the TBA test method,
developed by Uchiyama M. (1978).
2.2.4.3. Measurement of Red blood cell MDA


10
Blood samples of patients with colon cancer for MDA index
determination are taken from peripheral veins. Next, the blood
sample was centrifuged at a speed of 3000 rpm for about 10 minutes
to separate plasma and red blood cells. The red blood cells were
stored at 40C before being analyzed for MDA index. The
determination method is the same as for the tissue sample, but because

it is difficult to measure the weight of the erythrocyte membrane (or
red blood cell membrane) in the blood sample, therefore to
determine the MDA content on erythrocyte membrane, it is necessary
to determine the protein content of the erythrocyte membrane and
MDA value calculated on 1 mg of red blood protein.
2.2.5. Research criteria
2.2.5.1. Criterion on characteristics of the research group
Including criteria: age, gender, body mass index, anemia,
neutrophil/lymphocyte ratio (NLR), CEA concentration, characteristics
of radical surgery, postoperative tumor anatomic pathology.
3.2.5.2. Criterion on early results after surgery
Including criteria: complications in surgery, death - complications
after surgery, time of postoperative ileus, number of fever days after
surgery, time of hospitalization after surgery.
2.2.5.3. Criterion on the MDA content
Including 3 criteria: MDA content in tumor tissue, MDA content
in colon normal tissue (taken from tumor edge > 5cm) cells before
surgery taken at the time before surgery. The MDA concentration in the
tissue was measured in µg/g sample, the MDA concentration of peripheral
red blood cells before surgery was measured in µg/mg Protein.
2.2.5.4. Criterion on changes of erythrocyte MDA content after surgery


11
Peripheral erythrocyte MDA at 3 times: 1 day after surgery (after
24 hours), 3 days after surgery (after 72 hours) and 7 days after
surgery (after 168 hours). The MDA content of blood samples after
surgery was also measured in µg/mg Protein.
2.2.5. Data processing method
Comparing MDA values at four points before and after surgery

using Friedman test, comparing MDA values between two points or
between two tissue positions in the colon using the paired samples
Wilcoxon test. The statistical analysis was performed by SPSS 20.0,
the difference was statistically significant if p <0.05.
2.3. Ethical issues in research
All patients voluntarily participate in the research and the research
does not affect the quality of treatment, does not cause invasion, damage
to patients. For MDA testing in this study, patients do not have to pay.
CHAPTER 3
RESEARCH RESULTS
3.1. Characteristics of the research group and early
results after surgery
3.1.1. Age, gender, and body mass index
Average age: 59.8 ± 11.9 (29 - 87). Male: 42 patients (56.8%).
Female: 32 patients (43.2%). Male/Female ratio: 1.31/1. Weight: normal
62.2%; underweight 21.6%; overweight 16.2%; No patients had obesity.
3.1.2. Blood tests before surgery
Anemia: 39 patients (52.7%). NLR ≥ 4: 20 patients (27%). CEA
concentration before surgery > 10 ng/ml: 19 patients (25.7%).
3.1.3. Anatomical Pathology after surgery
- Right colon cancer: 31 patients (41.9%), Left colon cancer: 43
patients (58.1%), sigma colon cancer accounts for the highest rate:


12
44.6%. The average tumor size is 6.1 ± 2.4 cm (2 - 12cm). There
were 19 patients (25.6%) having tumor adhering to adjacent organs.
- The average number of lymph nodes dredged in one patient
was 15.5 ± 7.7 nodes (2 - 38). Number of patients with lymph nodes
having ≥ 12 lymph nodes: 47 patients (63.5%). The average length of

the removed colon segment is 31.6 ± 17.1 (12 - 85cm).
- Patients in Stage I, II, III correspondingly were 11 patients
(14.9%), 32 patients (43.2%) and 31 patients (41.9%). The rate of patients
with
lymph node metastasis: 41.9%, invasion T4: 33 patients (44.6%).
3.1.4. Radical surgery
- Laparoscopic surgery: 42 patients and open surgery: 32 patients,
Colostomy: 7 patients (9.5%). Expanding surgery: 14 patients
(18.9%), of which 5 patients with total colectomy. Most patients with
expanding surgery were those who underwent open surgery (13/14).
- The average length of time required to perform a surgical
procedure: 134.6 ± 38.7 minutes (75 - 270).
3.1.5. Early results after radical surgery
- No complications in surgery, death after surgery: 1 patient. The
rate of complications after surgery: 4 patients (5.4%).
- Average postoperative ileus time: 81.1 ± 22.2 hours (34 - 130 hours).
Average number of fever days after surgery: 1.7 ± 1.2 days (1 - 7 days).
Average length of hospital stay after surgery: 9.5 ± 2.9 days (6 - 21 days).
3.2. MDA content result in patients with colon cancer before
radical surgery
3.2.1. MDA content in tumors tissue, normal tissue of colon and
peripheral red blood cells


MDA content (µg/g sample)

13

4

3

2

1

0

Normal Tissue

Tumor Tissue

Chart 3.3. Comparison of MDA content of tumor tissue and normal
colon tissue
Table 3.12. MDA content in tumor tissue, colon normal tissue and
peripheral red blood cells
MDA
n
Min
Max
Average
Median
p*
Normal tissue
74
0.58
3.40
1.52 ± 0.56
1.40
(µg/g sample)

0.005
Tumor tissue
74
0.55
4.35
1.73 ± 0.76
1.52
(µg/g sample)
Red blood cells
74
0.020 0,.624 0.167 ± 0.10
0.142
(µg/mg Protein)
*Wilcoxon test

- MDA content of tumor tissue was higher than that of normal
colon tissue with p <0.05. There was a correlation between MDA
content of tumor tissue and normal tissue with Spearman
correlation coefficient: rs = 0.549; p <0.001.
- There was no correlation between red blood cell MDA and
MDA content of tumor tissue and normal tissue.
3.2.2. Analysis of tumor tissue MDA content based on a number
of clinical and pathological factors
Table 3.19. MDA content of tumor tissue according to the stage disease
Element
n
Average MDA content
p*

14

I
II
III

11
Disease
32
stage
31
Total
74
* Mann-Whitney test

(µg/g sample)
1.68 ± 0.61
1.63 ± 0.59
1.85 ± 0.94
1.73 ± 0.76

0.890

Table 3.21. MDA content of tumor tissue according to tumor position.
Average MDA content
Element
n
p*
(µg/g sample)
Colon P

31
1.92 ± 0.71
Tumor
0.017
position
Colon T
43
1.59 ± 0.77
Total
74
1.73 ± 0.76
* Mann-Whitney test

- The average MDA content in tumor tissue of the right colon
cancer group higher than that of the left colon cancer group has
statistical significance with p <0.05.
- Analyze the tumor tissue MDA content by elements: Age (<60
and ≥ 60 years old), Gender (male and female), Preoperative anemia
(with and without anemia), Peripheral NLR (NLR <4 and ≥ 4), CEA
concentration (≤ 10 and > 10 ng/ml), Disease stage (I, II, III), tumor
size (<6cm and ≥ 6cm), see that the tumor tissue MDA content by
the above group of elements had no difference with p> 0.05.
3.2.3. Analysis of peripheral red blood cell MDA content before
surgery according to some clinical and pathological factors
Table 3.27. Red blood cell MDA content before surgery according to
Element
Disease
stage
Total

I
II
III

disease stage
Average MDA content
n
(µg/mg Protein)
11
0.232 ± 0.10
32
0.154 ± 0.10
31
0.158 ± 0.08
74
0.167 ± 0.10

p*
0.049


15
*Kruskal-Wallis test

Table 3.28. Red blood cell MDA content before surgery according to
Element
Tumor size

< 6cm
≥ 6cm

Total

tumor size
Average MDA content
n
(µg/mg Protein)
36
0.196 ± 0.11
38
0.140 ± 0.07
74
0.167 ± 0.10

p*
0.017

* Mann-Whitney test

- The preoperative RBC MDA content in the patient group of
stage I is higher than that in patient groups of stages II and III; in the
group with tumor size < 6cm higher than the group with tumor size ≥
6cm, it is statistically significant with p <0.05.
- Analyze the preoperative RBC MDA content by elements: Age
(<60 and ≥ 60 years old), Gender (male and female), Preoperative
anemia (with and without anemia), Peripheral leukemia ratio
(leukemia ratio <4 and ≥ 4), CEA concentration (≤ 10 and > 10
ng/ml), tumor position (right and left colon cancer), realize the same
result: the preoperative RBC MDA content by the above group of
elements had no difference with p> 0.05.

3.3. Changes of RBC MDA content in colon cancer
patients after radical surgery
3.3.1. Red blood cell

MDA content at the point

before and after surgery
Table 3.30. Red blood cell MDA content at the points
MDA content
(µg/mg Protein)

n

min

max

Average

Median

Before surgery

60

0.045

0.624

0.145

1 day after surgery

60

0.070

0.789

0.168 ±
0.10
0.217 ±
0.13

0.186


16
3 days after surgery
7 days after surgery

60
60

p*
* Friedman test

0.055
0.034

0.557
0.726

0.190 ± 0.11
0.179 ±
0.12
0.001

0.147
0.152

Table 3.31. Compare the RBC MDA content paring at the points
MDAbefore surgery
MDA day 1
MDAday 3
MDAday 7
p* (n=60)
(0.168 ± 0.10)
(0.217 ± 0.13)
(0.190 ± 0.11) (0.179±0.12)
MDAbeforesurgery
1
(0,168 ± 0.10)
MDA day1
0.001
1
(0.217 ± 0.13)
MDAday3
0.795
0.020

1
(0.190 ± 0.11)
MDAday 7
0.985
0.003
0.942
1
(0.179 ± 0.12)
* Wilcoxon test

Chart 3.5. Comparing RBC MDA content at different points
- Immediately after surgery, the MDA content of red blood cells
increases and then gradually decreases. At the point 1 day after
surgery, the RBC MDA content reached the highest, it was higher
than other times and had statistical significance with p <0.05; The
difference in RBC MDA content at the time before surgery, 3 days


17
after surgery, 7 days after surgery was not statistically significant
with p> 0.05 (Willcoxon test).
3.3.2. Changes in MDA content of red blood cells after surgery
according to surgical characteristics
Table 3.32. RBC MDA content at different points according to surgery method
Surgery method
MDA content
n
p*
Laparoscopy
Open surgery

(µg/mg Protein)
(n=34)
(n=26)
Before surgery
60
0.174 ± 0.11
0.161 ± 0.09
0.536
1 day after surgery
60
0.233 ± 0.13
0.197 ± 0.11
0.187
3 days after surgery
60
0.200 ± 0.12
0.177 ± 0.11
0.408
7 days after surgery
60
0.200 ± 0.14
0.151 ± 0.09
0.072
p**
0.005
0.039
* Mann-Whitney test
** Friedman test

Table 3.35. RBC MDA content at different points according to

surgery duration
Surgery duration (SD)
MDA content
n
p*
(µg/mg Protein)
< 130 mins (n=30) ≥ 130 mins (n=30)
Before surgery
60
0.186 ± 0.12
0.151 ± 0.07
0.387
1 day after surgery
60
0.227 ± 0.15
0.208 ± 0.09
0.912
3 days after surgery
60
0.195 ± 0.14
0.184 ± 0.09
0.802
7 days after surgery
60
0.192 ± 0.15
0.165 ± 0.07
0.756
p**
0.014
0.002

* Mann-Whitney test
** Friedman test

- Comparing the pairing of points by the laparoscopic group and
open surgery group indicated that the RBC MDA content in the
laparoscopic group at the point of 3 days after surgery lower that of 1
day after surgery had statistical significance (p <0.05), while in the
open surgery group, the RBC MDA content at 3 days after surgery
and 1 day after surgery had no difference (p> 0.05).
- Comparing the pairing of points by surgery duration: SD < 130
mins and SD ≥ 130 mins showed that in the group with SD < 130 mins,
the difference in RBC MDA content of 1 day after surgery compared


18
with before surgery was not statistically significant with p> 0.05;
meanwhile, in the group with SD ≥ 130 mins, the RBC MDA content
of 1 day after surgery and 3 days after surgery were higher than that
before surgery, it was statistical significant with p <0.05.
3.3.3. Changes in RBC MDA after surgery related to early
postoperative results
Table 3.40. RBC MDA content at different points according to
postoperative ileus time
postoperative ileus
MDA content
time (PIT)
n
p*
(µg/mg Protein)
< 72 hrs (n=25)

≥ 72 hrs (n=35)
Before surgery
60
0.147 ± 0.07
0.184 ± 0.11
0.393
1 day after surgery
60
0.183 ± 0.07
0.242 ± 0.15
0.304
3 days after surgery
60
0.149 ± 0.06
0.219 ± 0.14
0.078
7 days after surgery
60
0.154 ± 0.07
0.196 ± 0.14
0.664
p**
0.004
0.039
* Mann-Whitney test
** Friedman test

- Comparing the pairing of points by group: PIT< 72 hrs and
PIT ≥ 72 hrs showed that the RBC MDA content in group PIT < 72
hrs at the point of 3 days after surgery lower than that at the point of

1 day after surgery had statistical significant (p <0.05), while in
group PIT ≥ 72 hrs, the RBC MDA content at 3 days after surgery
and 1 day after surgery had no difference (p> 0.05).
Table 3.43. RBC MDA content at different points according to
number of fever days after surgery
MDA Content
(µg/mg Protein)

n

Before surgery
1 day after surgery
3 days after surgery
7 days after surgery

60
60
60
60

Number of fever days after
surgery (NFDAS)
< 3 days (n=48)
≥ 3 days (n=12)
0.159 ± 0.10
0.205 ± 0.09
0.207 ± 0.13
0.257 ± 0.07
0.182 ± 0.11
0.224 ± 0.13

0.164 ± 0.10
0.238 ± 0.18

p*
0.093
0.026
0.139
0.177


19
p**

0.007

0.04

* Mann-Whitney test
** Friedman test

- Comparing the pairing of points by group: NFDAS < 3 days and
NFDAS ≥ 3 days indicated that for group NFDAS < 3 days, the RBC
MDA content at the point of 3 days after surgery and 7 days after
surgery lower than that at the point of 1 day after surgery had statistical
significant (p <0.05), while in group NFDAS ≥ 3 days the RBC MDA
content at the point of 3 days after surgery and 7 days after surgery had
no difference compared to 1 day after surgery (p> 0.05).
Table 3.46. RBC MDAcontent at different points according to length of hospital stay
MDA content
(µg/mg Protein)

n

Before surgery

Length of hospital stay
after surgery (LHSAS)

p*

< 10 days (n=35)

≥10 days(n=25)

60

0.139 ± 0.06

0.210 ± 0.13

0.067

1 day after surgery

60

0.188 ± 0.08

0.258 ± 0.16

0.144

3 days after surgery

60

0.168 ± 0.09

0.221 ± 0.14

0.175

7 days after surgery

60

0.157 ± 0.06

0.209 ± 0.17

0.893

0.015

0.017

p**
* Mann-Whitney test
** Friedman test

- Comparing the pairing of points by group: LHSAS < 10 days and
LHSAS ≥ 10 days indicated that for group LHSAS < 10 days the RBC
MDA content at the point of 3 days after surgery and 7 days after
surgery lower than that at the point of 1 day after surgery had statistical
significant (p <0.05), while in group LHSAS ≥ 10 days the RBC MDA
content at the point of 3 days after surgery and 7 days after surgery had
no difference compared to 1 day after surgery (p> 0.05).
DISCUSSION


20
4.1. Characteristics of research group and early
results after surgery
In this study, only patients in stage I, II and III who underwent
radical surgery were included, we excluded cases of incomplete
tumor resection and had distant metastases or had complication
required for an emergency surgery. However, through the obtained
results, we realized that the characteristics of the research group such
as: average age, age group distribution, male/female ratio, anemia,
preoperative CEA concentration, tumor histopathology… as well as
the early results after surgery had no difference with the previous
domestic studies on colon cancer.
The neutrophil to lymphocyte ratio (NLR) in peripheral blood
before surgery is an index reflecting inflammatory response, recently
concerned by many researchers. In this research, tumors invadin
adjacent organs often have a NLR ≥ 4, indicating that the tumor has
caused a systemic inflammatory response.
4.2. Characteristics of MDA content before surgery in colon
cancer patients being treated with radical surgery
4.2.1. Compare MDA content in tumor tissue, normal colon tissue

and peripheral red blood cells
To explore the characteristics of MDA content before surgery in
patients with colon cancer who were treated with radical surgery, we
conducted a quantification of MDA in 3 biological samples: tumor
tissue, normal colon tissue taken at least 5cm far from the tumor and
peripheral red blood cells. Similar to the results of Hendrickse C.
(1994), Skrzydlewska E. (2005), our research results show that the
MDA content in tumor tissue is higher than that in normal colon
tissue. Especially, in the study of Veljković A. (2016), the MDA
concentrations in tumor tissue and surrounding tissue are higher than
healthy tissue far from the tumor.


21
The increase in MDA levels in the diseased tissue in this study
once again proves that although the exact mechanism of oxidative
stress in colon cancer is not fully known, lipid peroxidation takes place
more strongly in cancerous cells compared to healthy colon cells in
patients with colon cancer.
In addition, the results of analyzing the correlation between
MDA content of tumors and MDA of normal tissue indicated that
they have a relatively close positive correlation, and that oxidative
stress is not only increasing in cancerous tissue but also appears in
healthy tissue of colon cancer patients. The analysis result does not
find out the correlation between MDA in red blood cell and MDA in
tumor tissue as well as normal colon tissue, and it indicates that the
typical biological activity of colon cancer which may lead to oxidative
stress in the tumor tissue has distinct characteristics compared to that
in blood tissue.
4.2.2. Factors affecting MDA content in tumor tissue and MDA in

peripheral red blood cells
Surveying some clinical and subclinical factors such as age, gender,
anemia, leukocyte ratio, CEA concentration, tumor anatomic
pathology, research results show that among the above factors, only
some tumor characteristics are related to MDA content in tumor
tissue and MDA in peripheral blood cells before surgery.
MDA content of tumor tissue in the right colon cancer is higher
than that in the left colon cancer, reflecting that lipid peroxidation takes
place more strongly in tumor of the right colon cancer. This result is
consistent with the study of Bauer K.M (2012) when detecting that
differences in disease progression between right and left colon cancer
are related to gene governing the activity of the enzyme NADPH
oxidase 4 (NOX4) which is one type of NADPH oxidase enzyme
family, and the inhibition or activation of this enzyme leads to an
increase or decrease in the production of oxygen free radicals.


22
With elements – disease stage and tumor size – in the research,
the MDA content of tumor tissue between the disease stages and
groups of tumor size did not have difference, while the red blood cell
MDA content is higher for tumors in stage I and for tumor size <
6cm. Our results are different when compared to some previous
studies. Skrzydlewska E. (2005) found the MDA in tumor tissue was
the lowest in the colorectal cancer stage II, the highest in stage IV.
Yücel A.F. (2012) found that the MDA value in blood of colorectal
cancer gradually increased with the disease stage, but this study
quantified MDA in plasma (different from our quantification on red
blood cells). Inokuma T. (2009) realized oxidative stress was higher
in larger tumors, but Gerber M. (1996) compared MDA according to

two tumor size groups : ≤ 5cm and > 5cm, he found that MDA higher
in smaller tumor size group, which is suitable for our study.
Therefore, due to the low number of patients in stage I of the study,
only 11 patients, so it is necessary to further research to confirm,
because if this result is true, it is significant in early diagnosis.
4.3. Changes of red blood cell MDA content in colon cancer
patients after radical surgery
The comparison results show that, 1 day after surgery, the MDA
concentration increased compared to before the surgery and until 3
days and 7 days after surgery, the MDA concentration decreased
significantly compared to 1 day after surgery, but still not lower than
the time before the surgery. Similar to the research results of other
authors, our results once again confirm the impact of radical surgery
procedure on the oxidative balance in colon cancer patients. At the
time 1 day after surgery, the elevation of MDA proves that the body's
antioxidant system is unable to clear up the free radicals generated
too much during surgery. This “clean-up” process continues to do and
until the 3rd day after surgery, the level of oxidative stress has
decreased significantly, corresponding to the clinical-ending-