Currently, there are no effective preventive strategies for pancreatic cancer. Obesity has been increasingly recognized as a strong but modifiable risk factor of pancreatic cancer. In this article, we aim to review the literature regarding weight loss on prevention of pancreatic cancer. Epidemiological and laboratory studies have shown that obesity is associated with increased incidence of pancreatic cancer and potentially worse cancer outcome. Whereas the underlying pathomechanisms remain unclear, chronic inflammation, insulin resistance, and altered intestinal microbiota are all implicated in the carcinogenic effect of obesity. Weight loss, especially the durable and significant weight loss after bariatric surgery, has been shown to reduce the risks of multiple cancers and may become a good intervention for pancreatic cancer prevention.

Background: Bariatric surgery is proven to change eating behavior and cause sustained weight loss, yet the exact mechanisms underlying these changes are not clearly understood. We explore this in a novel way by examining how bariatric surgery affects the brain–gut–microbiome (BGM) axis. Methods: Patient demographics, serum, stool, eating behavior questionnaires, and brain magnetic resonance imaging (MRI) were collected before and 6 months after laparoscopic sleeve gastrectomy (LSG). Differences in eating behavior and brain morphology and resting-state functional connectivity in core reward regions were correlated with serum metabolite and 16S microbiome data. Results: LSG resulted in significant weight loss and improvement in maladaptive eating behaviors as measured by the Yale Food Addiction Scale (YFAS). Brain imaging showed a significant increase in brain volume of the putamen (p.adj < 0.05) and amygdala (p.adj < 0.05) after surgery. Resting-state connectivity between the precuneus and the putamen was significantly reduced after LSG (p.adj = 0.046). This change was associated with YFAS symptom count. Bacteroides, Ruminococcus, and Holdemanella were associated with reduced connectivity between these areas. Metabolomic profiles showed a positive correlation between this brain connection and a phosphatidylcholine metabolite. Conclusion: Bariatric surgery modulates brain networks that affect eating behavior, potentially through effects on the gut microbiota and its metabolites.

Background. Although it is well known that obesity is a risk factor for gastrointestinal (GI) cancer, it is not well established if obesity can cause earlier GI cancer onset. Methods. A cross-sectional study examining the linked 2004–2008 California Cancer Registry Patient Discharge Database was performed to evaluate the association between obesity and onset age among four gastrointestinal cancers, including esophageal, gastric, pancreatic, and colorectal cancers. Regression models were constructed to adjust for other carcinogenic factors. Results. The diagnosis of obesity (BMI > 30) was associated with a reduction in diagnosis age across all four cancer types: 3.25 ± 0.53 years for gastric cancer, 4.56 ± 0.18 years for colorectal cancer, 4.73 ± 0.73 years for esophageal cancer, and 5.35 ± 0.72 for pancreatic cancer. The diagnosis of morbid obesity (BMI > 40) was associated with a more pronounced reduction in the age of diagnosis: 5.48 ± 0.96 years for gastric cancer, 7.75 ± 0.30 years for colorectal cancer, 7.67 ± 1.26 years for esophageal cancer, and 8.19 ± 1.25 years for pancreatic cancer. Both morbid obesity and obesity remained strongly associated with earlier cancer diagnosis for all four cancer types even after adjusting for other available cancer risk factors. Conclusions. The diagnosis of obesity, especially morbid obesity, was associated with a significantly earlier gastrointestinal cancer onset in California. Further research with prospective cohort data may be required to establish the causal relationship between obesity and cancer onset age.

To the Editor The Viewpoint by Dr Massetti and colleagues emphasized the link between obesity and cancer and called for more robust clinical intervention to prevent and treat obesity.¹ The authors proposed that sustainable weight loss be achieved by comprehensive strategies that support patients’ efforts to make significant lifestyle changes. However, most published studies have shown that the long-term success rate of lifestyle changes is low. Although lifestyle changes may be sufficient to reduce body weight prior to sustained obesity, once obesity is established, body weight seems to become biologically fixed and lifestyle programs become less effective.²