Bariatric surgery significantly reduced the risk of cancer in people with non-alcoholic liver disease (NAFLD) with obesity, according to findings published in Gastroenterology.

“We knew that obesity leads to certain problems, including cancer, but no one had ever looked at it the other way around—whether weight loss actually reduced the risk of those cancers,” Vinod K. Rustgi, MD, of the Rutgers Robert Wood Johnson School of Medicine, in New Jersey, said in a press release. “Our study showed that all cancers were decreased, but obesity-related cancers in particular were decreased even more.”

Arising from the accumulation of fat in the liver, NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are responsible for a growing proportion of advanced liver disease worldwide. As a result of inflammation, NAFLD can lead to the buildup of scar tissue (fibrosis), cirrhosis (advanced scarring) and even liver cancer. With no approved drugs to treat fatty liver disease, its management relies on lifestyle changes, such as diet and exercise.

NAFLD is associated with obesity, which raises the risk of several types of cancer. Rustgi and his colleagues examined the impact of bariatric surgery on cancer risk in people with NAFLD and extreme obesity. Bariatric surgery—gastric bypass and related procedures—alters the gastrointestinal tract so as to make weight loss more achievable for people with severe obesity.

The researchers conducted a retrospective cohort study among individuals ages 18 to 64 with severe obesity who were recently diagnosed with NAFLD between 2007 and 2017. The team included 98,090 participants, of whom 33,435 (34%) underwent bariatric surgery.

Among those who did not undergo bariatric surgery, 1,898 people developed cancer over 115,890 person-years of follow-up. On the other hand, there were 925 cancer cases over 67,390 person-years among those who did not have surgery.

Among those who underwent bariatric surgery, the risk of all cancers dropped by 18%, while the risk of obesity-related cancers fell by 25%, respectively. Specifically, the researchers noted a reduction in the risk of colorectal, pancreatic, thyroid and endometrial cancer as well as hepatocellular carcinoma (the most common type of liver cancer) and multiple myeloma. Moreover, the risk of developing cancer was especially reduced for individuals with cirrhosis who underwent bariatric surgery (a 52% drop) compared with those who did not have cirrhosis (a 38% drop).

“Though bariatric surgery is a more aggressive approach than lifestyle modifications, surgery may provide additional benefits, such as improved quality of life and decreased long-term health care costs,” suggested the researchers.

Click here to read the study in Gastroenterology.

Click here to learn more about fatty liver disease.