A recent study in JAMA surgery followed almost 1 million - that's right 1 MILLION patients - with severe obesity in France between 2010 and 2017. These participants were divided into those who underwent bariatric surgery (the surgical group) and thoes who did not (control group). These two groups were then compared over the years, with researchers looking for rates of esophageal and gastric cancer.
Of the near million patients, about a third underwent bariatric surgery. 83 patients in the surgical group - an incidence of 4.9 per 100,000 population per year - developed esophagogastric cancer. Meanwhile 254 patients, or 6.9 per 100,000 population per year developed esophagogasttric cancer. Essentially, the control group was 1.42 times more likely to develop cancer than those in the surgical group. Additionally, overall mortality, or the risk of death, was also significantly lower in the surgical group.
The authors noted that, after surgery, there is a balance of protective factors and risk factors. Protective factors include weight loss, metabolic effects and eradication of H.Pylori infection. Risk factors include reflux disease and bile reflux. After bariatric surgery, it appears that the protective factors outweight the risk factors.
We note that this is not the first study to demonstrate bariatric surgery's protective effect against cancer. The SPLENDID study showed a 32% decreased risk in 10-year obesity-related cancer incidence (a composite of 13 cancer types, including esophageal adenocarcinoma and stomach or gastric cancer) following weight loss with bariatric surgery.