Study the Malondialdehyde content in patients with colon cancer who underwent radical surgery treatment. Evaluate the changes in red blood cell Malondialdehyde content of patients with colon cancer after radical surgery.
MINISTRY OF EDUCATION MINISTRY OF AND TRAINING 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: National Library Library of Vietnam Military Medical University LIST OF PUBLISHED RESEARCH WORKS BY THE AUTHOR RELATED TO THE THESIS 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): 4450 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): 213219 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): 7175 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 Oxygenfree 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 oxygenfree 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: Study the Malondialdehyde content in patients with colon cancer who underwent radical surgery treatment 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: 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. * 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 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 KRas, 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 ROS producing enzymes such as XO (xanthine oxidase), Cox (Cyclooxygenase) and especially NADPH oxidase (nicotinamide adenine dinucleotide phosphateoxidase) or also called Nox. Abdominal surgery also increases free radicals and oxidative stress through the mechanism of ischemiareperfusion 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 stress such as: Carbonyl proteins (Product of protein oxidation process), 8OHdG (Product of DNA oxidation process) However, the product which is used the most in studies to assess oxidative stress 10 in general and in abdominal surgery in particular is Malondialdehy (MDA) of lipid peroxidation. According to PappasGogos 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 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 16 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) 17 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