Bariatric Surgery is Associated with Reduced Risk of Pancreatic Cancer: Analysis of a US National Database

Stephen Firkins, MD

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death despite only accounting for 3% of all new cancer diagnoses.¹ Obesity is a well-known risk factor for multiple types of cancer, including PDAC. In fact, there exists a relative risk of PDAC of 1.10 for every 5-unit increment increase in body mass index (BMI).² While bariatric surgery has been demonstrated to reduce overall cancer incidence and mortality, conflicting data exist regarding the effects of bariatric surgery on PDAC.^3-9

We performed a retrospective case-control study utilizing the National Inpatient Sample (NIS) database from October 2015 to December 2020. All adult subjects (age ≥18 years) with a BMI >40 kg/m2 or >35 kg/m2 with ≥1 metabolic comorbidity were identified and stratified into those with and without a history of bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy).

International Classification of Diseases, Tenth Edition Clinical Modification (ICD-10-CM) codes were used to define variables of interest. Baseline characteristics and comorbidities among the 2 groups were compared using chi-squared and Wilcoxon rank-sum tests and logistic regression analysis was performed to assess the risk of PDAC after adjusting for multiple risk factors, including tobacco use, acute and chronic pancreatitis, diabetes mellitus and various stages of obesity.

Over 19 million subjects were included, 1,656,329 of whom had a history of bariatric surgery. Patients with a history of bariatric surgery were significantly younger, more frequently female (75% vs 58%), had higher rates of class 3 obesity (69% vs 52%) and lower prevalence of hypertension, hyperlipidemia, chronic kidney disease, Charlson Comorbidity Index (CCI) ≥3, tobacco use, acute and chronic pancreatitis and pancreatic cancer (0.1% vs 0.2%) while having a higher prevalence of OSA (P <.001). Additionally, in-hospital mortality (0.5% vs 1.8%), total hospital charges and overall length of stay were lower in the bariatric surgery cohort compared to the nonsurgical cohort (P <.001). After adjusting for multiple comorbidities and risk factors, history of bariatric surgery was demonstrated to significantly reduce the risk of PDAC on both univariable (odds ratio [OR], 0.50; 95% confidence interval [CI], 0.44 - 0.56) and multivariable analysis (OR, 0.68; 95% CI, 0.61 - 0.77).

This is the largest analysis to date investigating the effects of bariatric surgery on pancreatic cancer risk reduction and serves to clarify previously inconclusive data. We have shown bariatric surgery to exhibit an independently protective effect against PDAC oncogenesis. It is reasonable to suggest that patients at increased risk of PDAC as well as other obesity-related malignancies may be recommended for surgically-assisted weight loss earlier and more frequently.

With advancements in minimally invasive bariatric procedures, expanding patient eligibility and indications for surgery, increasing utilization of bariatric surgery and endoscopic bariatric and metabolic therapies may help alleviate the growing burden of pancreatic cancer.

References

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