Effect of bariatric surgery on cancer risk: results from an emulated target trial using population-based data

Abstract

Background The impact of weight loss induced by bariatric surgery on cancer occurrence is controversial. To study the causal effect of bariatric surgery on cancer risk from an observational database, a target-trial emulation technique was used to mimic an RCT. Methods Data on patients admitted between 2010 and 2019 with a diagnosis of obesity were extracted from a national hospital discharge database. Criteria for inclusion included eligibility criteria for bariatric surgery and the absence of cancer in the 2 years following inclusion. The intervention arms were bariatric surgery versus no surgery. Outcomes were the occurrence of any cancer and obesity-related cancer; cancers not related to obesity were used as negative controls. Results A total of 1 140 347 patients eligible for bariatric surgery were included in the study. Some 288 604 patients (25.3 per cent) underwent bariatric surgery. A total of 48 411 cancers were identified, including 4483 in surgical patients and 43 928 among patients who did not receive bariatric surgery. Bariatric surgery was associated with a decrease in the risk of obesity-related cancer (hazard ratio (HR) 0.89, 95 per cent c.i. 0.83 to 0.95), whereas no significant effect of surgery was identified with regard to cancers not related to obesity (HR 0.96, 0.91 to 1.01). Conclusion When emulating a target trial from observational data, a reduction of 11 per cent in obesity-related cancer was found after bariatric surgery.

Does Bariatric Surgery Reduce the Risk of Colorectal Cancer in Individuals with Morbid Obesity? A Systematic Review and Meta-Analysis

“…As shown in Figure 1 , we included 18 [ 2 , 6 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ] studies in the quantitative and qualitative analysis. A meta-analysis was conducted on 12,517,893 patients.…”

“…Data to evaluate the primary outcome was retrieved from 17 studies [ 2 , 6 , 20 , 21 , 22 , 23 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…A sensitivity analysis was conducted due to high heterogeneity. Four studies [ 26 , 27 , 30 , 35 ] were found to be mainly responsible for the heterogeneity, but their exclusion failed to reduce it consistently; an advantage for individuals with obesity and a history of BS was still highlighted (RR: 0.57, 95% CI: 0.47–0.69, p = 0.0001, I 2 = 75%).…”

Obesity and cancer—extracellular matrix, angiogenesis, and adrenergic signaling as unusual suspects linking the two diseases

“…This is especially true for interventions leading to durable and significant weight loss such as bariatric surgery. A recent population-based study has shown that bariatric surgery decreases the risk of obesity-associated cancers, but does not change the incidence of cancers not related to obesity [ 136 ]. In the future, raising awareness about the connections between metabolic diseases and their long-term consequence on cancer among patients, physicians, and the research community will be critical to prevent the disease or improve treatment outcomes in cancer.…”

Editorial: Bariatric surgery—its influence on the development, diagnosis, and treatment of tumors

“…Evidence stemming from large-scale observational studies indicated reduced overall cancer incidence in patients undergoing bariatric surgery (10), and an array of recent studies confirmed reduced incidence of obesity related cancers after MBS (11,12), even for cancer types not associated with obesity, such as lung cancer (13,14). In contrast, certain bariatric techniques might increase the risk of acid-or biliary reflux disease, potentially leading to dysplastic changes of the distal esophageal mucosa (15).…”