- A new study found weight loss after undergoing bariatric surgery is associated with a significantly lower risk of cancer and reduced cancer mortality, especially among women.
- The National Cancer Institute lists obesity as a risk factor for cancer.
- The institute cites that obesity can increase the risk of death from cancer by 62% in women and 52% in men.
Bariatric surgery may help lower the risk of cancer in people with severe obesity, according to new research.
The study, published in Obesity Tuesday, found that bariatric surgery is associated with a significantly lower risk of cancer and reduced cancer mortality, especially among women.
Prior research has identified a strong link between obesity and cancer. The National Cancer Institute lists obesity as a risk factor for cancer, citing that it increases the risk of death from cancer by 62% in women and 52% in men.
It’s been less clear if and how voluntary weight loss impacts the risk of cancer.
The new findings add to growing evidence suggesting that weight-loss surgeries may play an important role in the prevention of cancer.
According to Dr. Anton Bilchik, MD, PhD, a surgical oncologist, chief of medicine, and Director of the Gastrointestinal and Hepatobiliary Program at Saint John’s Cancer Institute at Providence Saint John’s Health Center in Santa Monica, California, bariatric surgery is the most durable type of weight-loss, especially in people with severe obesity.
“This study suggests that it may reduce several cancer types that are hormonally-related such as breast cancer but also has an anti-inflammatory effect, which has been shown to be important in the development of several cancers,” Bilchik told Healthline.
The risk of cancer fell in people who had bariatric surgery
To better understand the association between weight loss and cancer, the researchers compared 38 years of health data of 21,827 people who had bariatric surgery, including gastric bypass, gastric banding, sleeve gastrectomy, and duodenal switch, to people who did not have bariatric surgery.
The research team found that those who underwent bariatric surgery had a 25% lower risk of developing any type of cancer compared to the non-surgical group and a 37% reduced risk of obesity-related cancers.
The risk reduction was greatest among women.
Women who underwent bariatric surgery had a 41% lower risk for hormonally driven cancer, including breast, ovarian, uterine, and colon cancer.
The cancer risk for men who had bariatric surgery was not lower than the group that did not have surgery.
Cancer also appeared less deadly in those who’d had bariatric surgery.
Among female bariatric surgery patients, the cancer mortality rate was 47% lower compared to the non-surgical group of women.
Lastly, the report found that cancer is being detected at earlier stages.
“The results of the study strongly suggest not only is cancer being prevented (lower incidence) but cancer is being delayed (detected at earlier stages),” says the corresponding author of the study Ted D. Adams, PhD, MPH, a program director at Intermountain Health and an adjunct professor of internal medicine at the University of Utah.
For example, bariatric surgery patients may be more likely to participate in preventative cancer screenings and their results may be more accurate, the study suggests.
Why weight loss may impact cancer risk
Being overweight is linked to a higher risk of developing 13 different types of cancer, according to the Centers for Disease Control and Prevention (CDC).
Excess weight can contribute to inflammation, high levels of insulin, and altered sex hormones.
Per the CDC, the risk of cancer increases with the more excess weight a person has or gains.
Research investigating the link between obesity and cancer states the mechanism of why obesity may cause cancer is complex and poorly understood.
Dr. Mir Ali, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, says that obesity affects all organ systems in the body.
“Although the mechanism is not certain, obesity causes chronic inflammation, overproduction of insulin and other hormones that may stimulate abnormal cell growth,” Ali said.
The researchers suggest there appear to be many long-term health benefits of bariatric surgery, including reduced tumor development, less inflammation, and improved hormonal function.
The fact that rates of hormonally-driven cancers, like breast, ovarian, and uterine cancer, dropped in women who had bariatric surgery suggests that hormones may play a big role in cancer risk reduction, according to Adams.
More research is needed to better understand why bariatric surgery has such a significant impact on the risk of developing and dying from cancer.
“Hopefully, mechanistic discovery will lead to improved treatment and perhaps detection of cancers,” said Adams.
The bottom line:
Bariatric surgery may help lower the risk of cancer in people with severe obesity, new research shows. People who had bariatric surgery had a 25% lower risk of developing any type of cancer and a 37% reduced risk of obesity-related cancers. The researchers suspect weight-loss surgery may combat the development of cancer by reducing inflammation, improving insulin resistance, and altering hormonal function.