Adiposity, history of diabetes, and risk of pancreatic cancer in postmenopausal women

Abdominal obesity and digestive system cancer: a systematic review and meta-analysis of prospective studies

BACKGROUND

The diagnostic criteria for abdominal obesity are usually waist circumference or waist-to-hip ratio. The magnitude of the risks for cancers of the digestive system and abdominal obesity is unknown. To assess whether abdominal obesity increases the risk of digestive cancer, we conducted a systematic review and meta-analysis of prospective cohort studies in a database.

METHODS

PubMed, Embase, and Web of Science databases were searched from their inception to December 2022. The 9-star Newcastle Ottawa Scale was used to assess  study quality. Pooled relative risks and 95% confidence intervals were calculated using fixed or random effect models respectively. The stability of the results was explored by one-by-one exclusion. Subgroup analysis was conducted to explore sources of heterogeneity. Publication bias was evaluated by Begg's and Egger's tests.

RESULTS

A total of 43 cohort studies were included. There were 42 and 31 studies in the meta-analysis of waist circumference and waist-to-hip ratio on digestive system cancer, respectively. The results of the meta-analysis revealed that the greater waist circumference and waist-to-hip ratio were correlated with increased incidence of digestive system cancers: waist circumference: RR 1.48, 95% CI 1.38-1.59, p < 0.001; waist-to-hip ratio: RR 1.33, 95% CI 1.28-1.38, p = 0.001. Subgroup analysis by cancer type showed that higher WC and WHR would increase the prevalence of LC, PC, GC, EC, and CRC. The sensitivity analysis was conducted by a one-by-one elimination method, and the results of the meta-analysis remained stable. It is proved that the results were robust by the trim-and-fill method.

CONCLUSIONS

There was evidence to suggest that abdominal obesity increased the incidence of digestive cancer, it is necessary to take appropriate measures to reduce abdominal obesity. Waist circumference and waist-to-hip ratio may be better predictors of digestive system cancers. However, the association between waist circumference and digestive system cancer was greater, so more attention should be paid to measuring abdominal obesity with waist circumference.

Metabolic Rewiring and Stemness: A Critical Attribute of Pancreatic Cancer Progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases with a poor 5-year survival rate. PDAC cells rely on various metabolic pathways to fuel their unlimited proliferation and metastasis. Reprogramming glucose, fatty acid, amino acid, and nucleic acid metabolisms contributes to PDAC cell growth. Cancer stem cells are the primary cell types that play a critical role in the progression and aggressiveness of PDAC. Emerging studies indicate that the cancer stem cells in PDAC tumors are heterogeneous and show specific metabolic dependencies. In addition, understanding specific metabolic signatures and factors that regulate these metabolic alterations in the cancer stem cells of PDAC paves the way for developing novel therapeutic strategies targeting CSCs. In this review, we discuss the current understanding of PDAC metabolism by specifically exploring the metabolic dependencies of cancer stem cells. We also review the current knowledge of targeting these metabolic factors that regulate CSC maintenance and PDAC progression.

Obesity and Pancreatic Cancer: Recent Progress in Epidemiology, Mechanisms and Bariatric Surgery

More than 30% of people in the United States (US) are classified as obese, and over 50% are considered significantly overweight. Importantly, obesity is a risk factor not only for the development of metabolic syndrome but also for many cancers, including pancreatic ductal adenocarcinoma (PDAC). PDAC is the third leading cause of cancer-related death, and 5-year survival of PDAC remains around 9% in the U.S. Obesity is a known risk factor for PDAC. Metabolic control and bariatric surgery, which is an effective treatment for severe obesity and allows massive weight loss, have been shown to reduce the risk of PDAC. It is therefore clear that elucidating the connection between obesity and PDAC is important for the identification of a novel marker and/or intervention point for obesity-related PDAC risk. In this review, we discussed recent progress in obesity-related PDAC in epidemiology, mechanisms, and potential cancer prevention effects of interventions, including bariatric surgery with preclinical and clinical studies.

Sustained Weight Loss, Weight Cycling, and Weight Gain During Adulthood and Pancreatic Cancer Incidence in the Women's Health Initiative

Pancreatic cancer (PC) is the fourth leading cause of cancer mortality among women in the United States. Obesity is positively associated with PC risk. Current health recommendations focus on weight maintenance for healthy-weight individuals and weight loss for overweight/obese individuals; however, little research has assessed associations between PC risk and changes in weight throughout the life course. Using prospective cohort study data, we examined the relationship between baseline adulthood weight patterns self-reported between 1993 and 1998 and PC risk in 136,834 postmenopausal women with 873 incident PC cases through September 30, 2015, in the Women's Health Initiative. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models, adjusting for age, smoking habits, heavy alcohol consumption, and body mass index. Compared with women with stable weight, no significant associations were found between steady weight gain (HR = 1.01, 95% CI: 0.83, 1.22), sustained weight loss (HR = 1.26, 95% CI: 0.85, 1.87), or weight cycling patterns (HR = 1.08, 95% CI: 0.89, 1.30) and PC. Results were similar when the outcome definition was restricted to pancreatic adenocarcinoma cases. Overall, we did not find evidence to suggest that weight changes in adulthood significantly impact PC risk among postmenopausal women.