30% weight loss, prevention of various cancers and diseases… The world of obesity metabolic surgery [건강 기상청 : 증상으로 본 질병]

[인터뷰] Park Seong-su, Professor of Gastroenterology, Korea University Anam Hospital
“Surgery for patients with severe obesity (BMI 35 or higher) without accompanying symptoms”
“Laparoscopic surgery without laparotomy, discharge after 3 to 5 days”

‘Obesity’ is now recognized as a fundamental disease that takes people’s lives beyond a cosmetic problem. This is because ‘severe obesity (BMI, body mass index 35 or higher)’ is pointed out as one of the fundamental factors that causes various cancers and cardiovascular diseases, the two leading causes of death in Koreans. Severe obesity causes metabolic diseases such as diabetes and high blood pressure, and if left untreated, it progresses to cardiovascular diseases and leads to death. Recently, it has also been revealed to be the cause of various cancers and related diseases.

The problem is that, although obesity treatment drugs that show dramatic weight loss effects have been developed recently, it is still difficult to achieve weight loss goals with only drug treatment, diet control, and exercise, and even if the goal is reached, it is virtually impossible to maintain it for a long time. Therefore, the alternative treatment method is surgical treatment, which is obesity metabolic surgery that dramatically reduces weight by removing the stomach to reduce its size or changing the path that food goes down. The goal of the surgery is 30% weight loss, and the treatment effect is much stronger than other treatments.

Is that why? Since 2019, when health insurance was applied, the number of obesity metabolic surgeries has increased rapidly, exceeding 2,100 cases. Last year, 2,453 cases were performed, and this year, it is expected that about 2,500 to 3,000 cases (estimated, based on statistics from the Health Insurance Review and Assessment Service) will be performed. As of 2021, about 600,000 cases were performed worldwide.
So what exactly is metabolic surgery, what kind of patients is it for, and how effective is it? To find out the answer, we met with Professor Park Sung-soo of the Department of Gastroenterology at Korea University Anam Hospital, a renowned expert in metabolic surgery. Professor Park established the first metabolic surgery center in Korea at Korea University Anam Hospital in 2015, and is currently serving as the director. He is also the vice president of the Korean Society for Metabolic and Bariatric Surgery. He is also the only Korean doctor to serve as an editorial committee member of the Journal of the American Society for Metabolic and Bariatric Surgery, and is the only full member of the Korean Academy of Medical Sciences, one of only two metabolic surgery specialists in Korea.

Professor Park said, “Bariatric metabolic surgery is performed to lower the mortality rate and increase the survival rate from various cancers and cardiovascular diseases through weight loss.” He added, “Bariatric metabolic surgery is a treatment method that not only has a stronger weight loss effect than medication, but is also excellent for maintaining the weight loss state.”

Sleeve gastrectomy is the most commonly performed procedure

What is Bariatric Surgery?

“Bariatric surgery is a surgery that reduces the volume of the stomach or changes the path that food goes down, causing hormonal changes in the body. In simple terms, it helps you eat less food by removing the enlarged stomach so that you feel full even after eating a little.”

What are the criteria for patients for whom obesity metabolic surgery is recommended?

“Generally, it is judged based on BMI (Body Mass Index), and patients with severe obesity with a BMI of 35 or higher are candidates for surgery even if they do not have accompanying symptoms. Those with a BMI of 30 to 35 are candidates for surgery if they have metabolic diseases such as diabetes, severe sleep apnea, or heart disease.”

What are the types of obesity metabolic surgery?

“There are many surgeries performed in this order: sleeve gastrectomy, which removes the stomach; gastric bypass, which separates the stomach into small pieces and connects it directly to the small intestine; and a combination of the two. Sleeve gastrectomy is the most commonly performed surgery, not only in Korea but also around the world, as it is relatively simple, has a fast recovery, and has few short-term complications. Although it is minor, the complication rate is 0.2% lower and the mortality rate is 0.03% lower than gastric bypass.

Gastric bypass is the second most common surgery, being almost as effective as sleeve gastrectomy. According to global statistics, as of 2021, about 600,000 bariatric surgeries were performed, of which 350,000 were sleeve gastrectomy and 200,000 were gastric bypass. In addition, there is gastric banding, which reduces the volume by tying the stomach with a band, but the short-term effect is not clear, and the side effects increase in the medium to long term, so it is no longer performed.”

Improvement of metabolic diseases…Reoperation rate less than 5%

Could you please explain the surgical method in more detail?

“Both sleeve gastrectomy and gastric bypass are performed laparoscopically, not open, unless there is a special reason. First, sleeve gastrectomy is a surgical procedure that reduces the stomach capacity and food intake by removing the D-shaped greater curvature of the stomach in a sleeve shape (I shape). When the stomach capacity is reduced, the secretion of hormones that affect food intake and appetite is suppressed, inducing weight loss. Roux-en-Y gastric bypass is a surgical procedure that separates the upper part of the stomach into a small pouch shape and connects the small intestine into a Y shape. By moving the point where food meets pancreatic juice and bile from the duodenum to the lower part of the small intestine, it preserves the function of the pancreas and prevents rapid increases in blood sugar levels.”

How do you choose a surgical method?

“The decision is made by comprehensively considering the patient’s situation and complications from the surgery. In the case of gastric bypass, there is a low chance of cancer developing in the remaining stomach area after surgery, but since endoscopy is impossible after this surgery, it is not easy to detect cancer. Therefore, if you have a family history of stomach cancer, it is better to avoid gastric bypass. Patients infected with Helicobacter pylori or smokers should also avoid gastric bypass. This is because smoking promotes gastric acid secretion, which can cause damage or ulcers at the surgical site. In the case of sleeve gastrectomy, gastroesophageal reflux can increase after surgery, so if you have severe gastroesophageal reflux disease, consider another surgery.”

Why do people lose weight after bariatric surgery?


“The most powerful reason is the reduced amount of food consumed, followed by a decrease in digestive power, which limits the absorption of nutrients from the food consumed. Other reasons include a decrease in the secretion of appetite-stimulating hormones. Recently, the beneficial intestinal bacteria (microbiome) changes caused by the surgery itself have been studied in various ways as an important weight loss mechanism.”

They say diabetes improves after metabolic surgery?

“Because a significant amount of weight loss occurs after surgery. Even for diabetic patients with normal weight, weight loss is essential to improve their condition. In addition, obesity metabolic surgery effectively reduces insulin resistance, which is the cause of diabetes, and improves insulin secretion function in the long term.”

What is the length of hospital stay and diet after surgery?

“Generally, discharge is possible within 3 to 5 days after surgery. If you have a serious internal disease, the hospitalization period may be extended to manage the disease. For 4 weeks after surgery, eat mainly liquid food such as rice cake soup. Rather than increasing the amount of food consumed, you should change the type of food you eat to protein-based food and prevent gastroesophageal reflux. Most patients with severe obesity already have elevated liver function due to fatty liver before surgery, so it is better not to drink alcohol after surgery. There is no specific food that you should not eat, but you should definitely avoid foods that are high in calories or sugar such as carbohydrates.”

Statistically, how much weight is lost and maintained after surgery?

“About 30% of the pre-operative weight is lost. I can’t say on average, but most surgical patients reach their lowest weight within two years and then maintain a 3% weight gain.”

What if I have a second surgery?

“Revision surgery is performed in cases where the stomach has expanded again, gastroesophageal reflux disease that cannot be treated with medication has occurred, or body weight has increased by more than 10% from the lowest point, which accounts for less than 5% of the total.”

Prevention of colon cancer, pancreatic cancer, bile duct cancer, etc.

I heard that a paper was published stating that metabolic surgery for obesity prevents major diseases such as cancer in addition to metabolic diseases?

“In a research paper (‘Association of bariatric surgery with indicated and unintended outcomes’) published in the international academic journal ‘Obesity Reviews’ in October 2023, in which the research team at Korea University Hospital, including myself, participated, it was revealed that bariatric metabolic surgery can definitely prevent gallbladder diseases such as gallstones, bile duct cancer, colon cancer, pancreatic cancer, and Crohn’s disease. In addition, the results showed that bariatric metabolic surgery can also prevent diverticular disease, gallbladder cancer, rectal cancer, acute pancreatitis, liver cancer, Barrett’s esophagus, and ulcerative colitis. Bariatric metabolic surgery generally aims to reduce body weight by 30%, but even with just a 20% weight loss, metabolic syndrome and the major diseases listed in the paper can be treated and prevented.”

What would you like to say to patients considering obesity metabolic surgery?


“Bariatric surgery is not simply about becoming slimmer, but it is an effective action and an important investment to protect my health from future diseases and improve my quality of life. If there is a patient suffering from severe obesity who is considering surgery, I recommend that you do not hesitate to consult with your primary care physician.”

2024-08-30 10:35:20