Research to be presented at Digestive Disease Week 2023 indicates that people who undergo bariatric surgery have less than half the risk for developing an obesity-associated cancer than their peers who do not receive weight loss 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, in a press release. “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.”
Chittajallu noted that although obesity has a strong association with cancer, there is limited evidence on the protective effects of bariatric surgery for the development of cancer.
To address this, his team compared cancer rates among 55,789 individuals from 47 US healthcare-organizations who underwent sleeve gastrectomy, gastric bypass, or gastric band surgery in 2002 with those among 55,789 individuals match for demographic factors, comorbidity, hormone therapy, and cancer screening modalities.
The researchers specifically looked at cancers with sufficient evidence to be considered associated with obesity: esophageal adenocarcinoma, multiple myeloma and cancers of the kidney, colon, rectum, stomach, liver, gallbladder, pancreas, ovary, endometrium, breast and thyroid. To reduce the risk for confounding by preexisitng cancers, the team only considered diagnoses that were made a year or more after bariatric surgery (or the time of obesity diagnosis in the control group).
During 10 years of follow-up the overall risk for developing an obesity-associated cancer was a significant 52% lower in the surgery group than in the control group. Specifically, the incidence was 4.0%. (n=2206) among people who received bariatric surgery versus 8.9% (n=4960) in those who did not.
The rates of liver (1.7 vs 4.1%), colon (0.4 vs 0.6%), ovarian (0.2 vs 0.4%), and breast (0.9 vs 1.3%) cancer were all significantly lower in the surgery group relative to the control group, with respective risk reductions of 63%, 36%, 35%. and 25%.
Chittajallu told Inside Precision Medicine that “the mechanisms responsible for reducing cancer risk after surgery still require further study [but the procedure] has been shown to decrease excess inflammation, elevate insulin and moderate hormone levels.”
DDW Council Chair Loren Laine MD, Professor of Medicine, Digestive Diseases, at Yale School of Medicine, said: “We know that obesity is clearly associated with a number of different cancers, so it makes logical sense that if you lose weight, that you will reduce that risk.” He added that in future, he would like to see whether there was a dose-response relationship between the amount of weight loss following bariatric surgery and cancer risk.
Chittajallu concluded that the findings support “the importance of treating obesity with bariatric surgery to reduce the societal and economic burden of cancer.”
