Bariatric Surgery and Cancer

By Jane Farrell

Bariatric (weight-loss) surgery may have a surprising – and welcome – side effect, according to a new study.

Just 4% of patients with obesity who underwent bariatric surgery developed obesity-associated cancer in a 10-year followup, compared to 8.9% among those who did not have a weight-loss procedure, according to a study to be presented in May 2023 at Digestive Disease Week® (DDW) 2023, a convention of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

“The primary benefit people consider when they think about bariatric surgery is weight loss and the accompanying physical and psychological benefits, such as improved blood pressure and diabetes,” said Dr. Vibhu Chittajallu, the study’s lead author and a gastroenterology fellow at Case Western Reserve University, and University Hospitals. “This study adds to the building evidence that the significant weight loss associated with bariatric surgery may have a protective effect against cancer formation as well.”

The study analyzed records of more than 55,700 patients with obesity who underwent bariatric surgery, comparing them with the same number of similar patients who did not have surgery. Researchers included patients who had sleeve gastrectomy, gastric bypass or gastric band procedures. The investigators controlled for risk factors that play a role in cancer formation, such as smoking history, alcohol use, heart disease and hormone therapies.

In 10 years of follow-up, the number of patients who developed obesity-associated cancers was 2,206 among those who underwent bariatric surgery, compared to 4,960 among those who did not have surgery.

The bariatric surgery cohort had consistently lower numbers of new cases for virtually all types of obesity-related cancer, including breast (501 vs. 751), colon (201 vs. 360), liver (969 vs. 2,198), pancreas (54 vs. 86), ovarian (130 vs. 214) and thyroid (154 vs. 175).

“We need more research to understand how bariatric surgery affects cancer risk, but the significant findings from this [research] suggest it’s an exciting avenue for further study,” Chittajallu said.