Does bariatric surgery reduce cancer risk? A review of the literature

Bariatric surgery has been shown to provide sustained weight loss and to decrease obesity-related mortality in most patients with morbid obesity, but its effect on cancer risk is less clear. Our aim was to review the published studies on the association between bariatric surgery and cancer risk.A literature search for relevant articles published in English, with no limitation on the year of publication, was conducted using PubMed. Studies reporting data on preoperative cancer, case reports, and publications with no abstract available were excluded.Overall, the published literature suggests that bariatric surgery may decrease risk of cancer, although this effect appears to be limited to women. However, two recent studies contradict these findings and state that risk of cancer has not been actually shown to decrease after surgery, and an increased risk of colorectal cancer has even been seen. Although most studies report lower cancer risk after bariatric surgery, the main limitations include their designs, which do not achieve the highest levels of evidence. Moreover, several mechanisms have been proposed to explain the protective effect of surgery, but the exact mechanisms have not been elucidated yet, which suggests the need for further research.Bariatric surgery may have a protective effect from overall cancer risk, mainly in women, but additional research is needed. Further research is also required to better examine the relationship between bariatric surgery and risk of colorectal cancer before confirming or dismissing the above reported higher risk, as well as the risk of esophagogastric cancer, which has not been adequately studied to date.