Bariatric Surgery May Reduce Risk of Esophageal, Gastric Cancers

Undergoing bariatric surgery for severe obesity was linked to a decreased incidence of esophageal and gastric cancer and overall in-hospital mortality, a French cohort study showed.

Among mostly women, the incidence rates of these cancers were 4.9 per 100,000 population per year for the group who underwent bariatric surgery versus 6.9 per 100,000 population per year for those who did not undergo surgery, for an incidence rate ratio of 1.42 (95% CI 1.11-1.82, P=0.005), reported Andrea Lazzati, MD, PhD, of the Centre Hospitalier Intercommunal de Créteil in France, and colleagues.

This difference was confirmed in a multivariable Cox proportional hazards regression model, with a hazard ratio for bariatric surgery of 0.76 (95% CI 0.59-0.98, P=0.03). Overall mortality was also significantly lower in the surgery group (HR 0.60, 95% CI 0.56-0.64, P<0.001), the authors noted in JAMA Surgery.

"It seems that the balance between protective factors (weight loss, metabolic effects, and eradication of H. pylori infection) and risk factors (GERD [gastroesophageal reflux disease] and bile reflux) for cancer after bariatric surgery is in favor of protective factors," Lazzati's group wrote.

Of note, in the regression model, a significant reduction in cancer incidence was not seen with adjustable gastric banding (HR 0.84, 95% CI 0.47-1.51, P=0.56) or sleeve gastrectomy (HR 0.86, 95% CI 0.63-1.18, P=0.35) compared with the control group, but the researchers did find a significant reduction in cancer incidence after gastric bypass (HR 0.62, 95% CI 0.40-0.95, P=0.02).

These findings serve as "an important step toward improving the understanding of potential lifetime risks of bariatric surgery and overall major health benefits of surgically induced weight loss," noted Piotr Gorecki, MD, and Michael Zenilman, MD, both of Weill Cornell Medicine in New York City, in an accompanying commentary.

While there has been "growing concern" that these popular bariatric procedures may lead to an uptick in adenocarcinomas due to their association with GERD and subsequent progression to Barrett esophagus, this study now provides both patients and clinicians with "reassurance of the protective clinical benefits of weight loss surgery," they wrote.

However, longer-term studies are still needed, Gorecki and Zenilman suggested, noting that some of these cancers could take years to develop.

This isn't the first study to demonstrate a protective benefit against cancer with bariatric surgery. The SPLENDID study, which was presented at the American Diabetes Association meeting last year, showed a 32% reduced risk in 10-year obesity-related cancer incidence following weight loss with bariatric surgery. This study included a composite of 13 cancer types, including esophageal adenocarcinoma and cancer of the gastric cardia.

For the current cohort study, Lazzati and team used data from a national discharge database, which included all surgical centers, in France from January 2010 through December 2017. They included 303,709 patients who underwent bariatric surgery (mean age 40.2, 80.9% women) matched with 605,140 patients who had severe obesity but did not undergo bariatric surgery (mean age 40.4, 82.8% women).

Mean follow-up time was 6.06 years in the surgery group and 5.62 years in the control group. A total of 337 patients had esophagogastric cancer: 83 in the surgery group and 254 in the control group.

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