JAMA: Surgical weight loss can greatly reduce the risk of cancer incidence and death

According to the World Health Organization (WHO), nearly 2 billion people worldwide are overweight or obese, and from 1975 to 2016, the global obesity rate nearly tripled, and 2.
8 million deaths due to overweight or obesity each year.

In fact, obesity not only leads to inconvenience and reduced exercise capacity, but also increases the risk
of metabolic diseases such as diabetes and cardiovascular and cerebrovascular diseases.
According to the US Centers for Disease Control and Prevention (CDC), obesity increases the risk of 13 cancers such as breast, liver, colorectal, pancreatic, and thyroid cancer, and is also associated with
an increased risk of death from a variety of cancers.

Bariatric surgery is currently the best way to lose weight, with an average weight loss of 20%-40%, and the weight loss effect can last for many years
.
So, can bariatric surgery reduce the risk of cancer development and death in obese people?

On June 3, 2022, the research team of Cleveland Clinic in the United States published the title "Association of Bariatric Surgery With Cancer Risk and Mortality in Adults With Obesity" in the international top medical journal "JAMA" Research paper
on the relationship between bariatric surgery and cancer risk and mortality in obese adults.

The study showed that for obese adults, weight loss through bariatric surgery was associated with
a 32% lower risk of obesity-related cancer development and a 48% lower risk of cancer-related death.

Dr.
Ali Aminian, the study's leader and director of the Institute for Weight Loss and Metabolism at Cleveland Clinic, said bariatric surgery is currently the most effective way
to treat obesity.
Obese patients can lose 20%-40% of their weight after surgery, and the effect can often be maintained for more than a decade
.
The study showed that the more weight lost through surgery to lose weight, the lower
the risk of cancer.

The study followed 30,318 obese patients at Cleveland Clinic for a long time, of which 5,053 obese adults underwent bariatric surgery between 2004 and 2017, and 25,265 obese adults did not undergo bariatric surgery at a 1:5 ratio.

The median age of the 30,318 obese patients was 46 years and the median body mass index (BMI) was 45, of which 77 percent were female and 73 percent white
.
The primary focus of the study was that these participants developed any of the 13 obesity-related cancers, with secondary endpoints of prevalence and mortality
from related cancers.

The 13 obesity-related cancers are: esophageal adenocarcinoma, renal cell carcinoma, postmenopausal breast cancer or breast cancer, cardia cancer, colon cancer, rectal cancer, liver cancer, gallbladder cancer, pancreatic cancer, ovarian cancer, uterine cancer, thyroid cancer, and multiple myeloma
.

Ten years later, the surgical weight loss group lost an average of 24.
8 kg compared to before surgery, or 19.
2%
less body weight.
People who did not undergo surgery to lose weight remained basically stable
.

2.
9% of those who underwent surgery to lose weight developed cancer, compared with 4.
9% of those who did not undergo surgery to lose weight
.
The adjusted risk ratio was 32%
lower for surgical dieters than for those who had not had surgery.

After 10 years, 0.
8% of people who lost weight surgically and 1.
4% of those who did not have surgery to lose weight died of cancer
.
The adjusted risk ratio was 48%
lower for surgical dieters than for those who did not have surgery.

This suggests that in obese adults, bariatric surgery is associated with
a significant reduction in cancer prevalence and cancer-related mortality compared to no surgery to lose weight.

The study further analyzed the proportion of 200 patients who underwent surgery to lose weight and 1331 patients who did not undergo surgery to lose weight developing any cancer, and the results showed that the proportion of those who underwent surgery to lose weight after 10 years developed any kind of cancer, compared with 8.
3% of those who did not undergo surgery, and the adjusted risk ratio was 17%
lower for surgical weight loss than for those who did not have surgery to lose weight.

The researchers noted that the benefits of bariatric surgery were demonstrated across a wide range of study participants, including women and men, young and old, and black and white patients
.
In addition, gastric bypass surgery and gastric sleeve resection are two bariatric procedures with similar benefits
.

Numerous studies have shown that weight loss or bariatric surgery has health benefits
for obese patients.
Previous research at Cleveland Clinic has shown that after bariatric surgery, weight loss can be sustained over time, and type 2 diabetes can be effectively controlled
.
They also found that bariatric surgery reduced the risk of
liver disease progression and serious heart complications for people with fatty liver.

The latest study shows that bariatric surgery is associated
with a significantly lower risk of cancer and death in obese adults.
This suggests that bariatric surgery is also a potential way
to help prevent cancer and reduce cancer mortality.
The research team said it will further explore the underlying mechanisms underlying the
reduced risk of cancer and death after bariatric surgery.

According to the American Cancer Society, obesity is the second most preventable cause of cancer in the United States after tobacco, and this study provides the best evidence
on the value of intentional weight loss in reducing cancer risk and mortality.

It is worth mentioning that many pharmaceutical companies have been working to develop obesity treatment drugs that can compete with the effects of bariatric surgery, but the actual results are not satisfactory
.

Until recently, on April 28, 2022, Eli Lilly published the results of a randomized controlled, double-blind Phase 3 clinical trial of its weight loss drug Tirzepatide, which showed that participants lost up to 22.
5% (24 kg) on average after 72 weeks of treatment
.
This is also the best effect of weight loss by drug to date, comparable to bariatric surgery, surpassing the phase 3 clinical slimming effect
of semaglutide developed by Novo Nordisk.

Eli Lilly said Tirzepatide is the first investigational drug to achieve an average weight loss effect of more than 20% in a Phase 3 clinical trial
.

Original source:

Ali Aminian，et al.
Association of Bariatric Surgery With Cancer Risk and Mortality in Adults With Obesity.
JAMA.
2022；327(24)：2423-2433.
doi：10.
1001/jama.
2022.
9009.