Researchers Explore Weight Loss’s Significant Impact on Cancer Risk

Vinod Rustgi
Vinod K. Rustgi, professor of medicine, clinical director of hepatology and director of the Center for Liver Diseases and Liver Masses at Robert Wood Johnson Medical School.
Steve Hockstein/

Bariatric surgery can significantly reduce the risk of cancer—particularly obesity-related cancers like pancreatic, colorectal, endometrial and thyroid—by as much as half in certain individuals, according to a study by researchers at Rutgers Robert Wood Johnson Medical School’s Center for Liver Diseases and Liver Masses.

The research, published in the journal Gastroenterology, is the first to show bariatric surgery significantly decreases the risk of cancer in individuals with severe obesity and nonalcoholic fatty liver disease (NAFLD), which affects people who drink little to no alcohol. The risk reduction is even more pronounced in individuals with NAFLD-cirrhosis of the liver, the researchers say.

“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,” said study author Vinod K. Rustgi, professor of medicine, clinical director of hepatology and director of the Center for Liver Diseases and Liver Masses, Robert Wood Johnson Medical School. “Our study showed that all cancers were decreased, but obesity-related cancers in particular were decreased even more.”

According to the study, the risk for all types of cancers decreased by 18 percent after bariatric surgery. The risk for obesity-related cancers as well as hepatocellular carcinoma and multiple myeloma was reduced by 25 percent. When comparing cirrhotic versus non-cirrhotic patients, overall cancer risk was reduced by 38 percent and the risk of obesity-related cancer was reduced by 52 percent.

The retrospective study looked at data of more than 98,000 privately insured individuals age 18 to 64 years old who were diagnosed with severe obesity and NAFLD between 2007 and 2017. Of those, more than a third (34.1 percent) subsequently had bariatric surgery.

The study results offer insight for clinicians and building blocks for future studies on the connection between NAFLD and cancer, Rustgi says.

“Understanding the connection between NAFLD and cancer may identify new targets and treatments,” Rustgi says.

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,” the researchers say.

The next step for center researchers, Rustgi says, is to explore whether this reduced cancer risk holds true for individuals with severe obesity who do not have NAFLD. They are also planning to study the mechanism by which this reduced risk occurs—whether factors such as hormonal changes induced by weight loss are the cause of reduced cancer risk, rather than just the weight loss itself, he says. In addition, center researchers currently are studying the impact of bariatric surgery on cardiovascular outcomes, such as a decrease in heart attacks, or a decrease in strokes.

Other study authors, all from RWJMS’s Division of Gastroenterology and Hepatology and the Center for Liver Diseases and Liver Masses, include Kapil Gupta, hepatology fellow; Carlos D. Minacapelli, research associate; Abhishek Bhurwal, gastroenterology fellow; You Li, research associate; Carolyn Catalano, advanced practice nurse; and Mohamed I. Elsaid, statistician.