Association Between Weight Loss and the Risk of Cancer after Bariatric Surgery

Assessing the state of obesity care: Quality, access, guidelines, and standards

Background

An international panel of obesity medicine experts from multiple professional organizations examined patterns of obesity care and current obesity treatment guidelines to identify areas requiring updating in response to emerging science and clinical evidence.

Aims

The panel focused on multiple medical health and societal issues influencing effective treatment of obesity and identified several unmet needs in the definition, assessment, and care of obesity.

Methods

The panel was held in Leesburg, Virginia in September 2019.

Results

The panelists recommended addressing these unmet needs in obesity medicine through research, education, evaluation of delivery and payment of care, and updating clinical practice guidelines (CPG) to better reflect obesity's pathophysiological basis and heterogeneity, as well as the disease's health, sociocultural, and economic complications; effects on quality of life; need for standards for quantitative comparison of treatment benefits, risks, and costs; and the need to more effectively integrate obesity treatment guidelines into routine clinical practice and to facilitate more direct clinician participation to improve public understanding of obesity as a disease with a pathophysiological basis. The panel also recommended that professional organizations working to improve the care of people with obesity collaborate via a working group to develop an updated, patient-focused, comprehensive CPG establishing standards of care, addressing identified needs, and providing for routine, periodic review and updating.

Conclusions

Unmet needs in the definition, assessment and treatment of obesity were identified and a blueprint to address these needs developed via a clinical practice guideline that can be utilized worldwide to respond to the increasing prevalence of obesity.

Trends in the burden of most common obesity-related cancers in 16 Southern Africa development community countries, 1990-2019. Findings from the global burden of disease study

Background

Obesity-related cancers in the 16 Southern African Development Community (SADC) countries is quite prominent. The changes and time trends of the burden of obesity-related cancers in developing countries like SADC remain largely unknown. A descriptive epidemiological analysis was conducted to assess the burden of obesity-related cancers, (liver, esophageal, breast, prostate, colon/rectal, leukemia, ovarian, uterine, pancreatic, kidney, gallbladder/biliary tract, and thyroid cancers) in SADC countries.

Methods

Data from the 2019 Global Burden of Diseases Study was used. Deaths extracted from vital registration, verbal autopsies and ICD codes. Cancer-type, mortality and prevalence per 100,000 population and 95% uncertainty intervals (UIs) were calculated using the Cause of Death Ensemble model and Spatio-Temporal Gaussian process with mixed effects regression models. Annual rates of change (AROCs) between 1990 and 2019 and the corresponding UIs were calculated.

Results

The top age-standardized mortality rates per 100,000 in 2019 for males were leukemia, 20.1(14.4-26.4), esophageal cancer, 15.1 (11.2-19.1), and colon and rectal cancer, 10.3 (8.6-12.6). For females, breast cancer, 20.6 (16.6-25.0), leukemia, 17.1 (11.4-23.7), and esophageal cancer, 8.3 (5.5-10.7), had the leading mortality rates. For males, AROC substantial (p < 0.05) increase for kidney cancer for 11 of the countries (AROC from 0.41% to 1.24%), colon cancer for eight of the countries (from 0.39% to 0.92%), and pancreatic cancer for seven countries (from 0.26% to 1.01%). In females, AROC showed substantial increase for pancreatic cancer for 13 of the countries from (0.34%-1.67%), nine countries for kidney cancer (from 0.27% to 1.02%), seven countries each for breast cancer (0.35%-1.13%), and ovarian cancer (from 0.33% to 1.21%).

Conclusions

There is need for location-specific and culturally appropriate strategies for better nutrition and weight control, and improved screening for all cancers. Health promotion messaging should target kidney, colon, pancreatic, and breast cancers and encourage clinically tested methods of reducing BMI such as increasing personal physical activity and adoption of effective dietary regimes.

Bariatric Surgery and Gut-Brain-Axis Driven Alterations in Cognition and Inflammation

Obesity is associated with systemic inflammation, comorbidities like diabetes, cardiovascular disease and several cancers, cognitive decline and structural and functional brain changes. To treat, or potentially prevent these related comorbidities, individuals with obesity must achieve long-term sustainable weight loss. Often life style interventions, such as dieting and increased physical activity are not successful in achieving long-term weight loss. Meanwhile bariatric surgery has emerged as a safe and effective procedure to treat obesity. Bariatric surgery causes changes in physiological processes, but it is still not fully understood which exact mechanisms are involved. The successful weight loss after bariatric surgery might depend on changes in various energy regulating hormones, such as ghrelin, glucagon-like peptide-1 and peptide YY. Moreover, changes in microbiota composition and white adipose tissue functionality might play a role. Here, we review the effect of obesity on neuroendocrine effects, microbiota composition and adipose tissue and how these may affect inflammation, brain structure and cognition. Finally, we will discuss how these obesity-related changes may improve after bariatric surgery.

Long-term cancer outcomes after bariatric surgery

OBJECTIVE

Obesity is associated with increased cancer risk. Because of the substantial and sustained weight loss following bariatric surgery, postsurgical patients are ideal to study the association of weight loss and cancer.

METHODS

Retrospectively (1982-2019), 21,837 bariatric surgery patients (surgery, 1982-2018) were matched 1:1 by age, sex, and BMI with a nonsurgical comparison group. Procedures included gastric bypass, gastric banding, sleeve gastrectomy, and duodenal switch. Primary outcomes included cancer incidence and mortality, stratified by obesity- and non-obesity-related cancers, sex, cancer stage, and procedure.

RESULTS

Bariatric surgery patients had a 25% lower risk of developing any cancers compared with a nonsurgical comparison group (hazard ratio [HR] 0.75; 95% CI 0.69-0.81; p < 0.001). Cancer incidence was lower among female (HR 0.67; 95% CI 0.62-0.74; p < 0.001) but not male surgery patients, with the HR lower for females than for males (p < 0.001). Female surgery patients had a 41% lower risk for obesity-related cancers (i.e., breast, ovarian, uterine, and colon) compared with nonsurgical females (HR 0.59; 95% CI 0.52-0.66; p < 0.001). Cancer mortality was significantly lower after surgery in females (HR 0.53; 95% CI 0.44-0.64; p < 0.001).

CONCLUSIONS

Bariatric surgery was associated with lower all-cancer and obesity-related cancer incidence among female patients. Cancer mortality was significantly lower among females in the surgical group versus the nonsurgical group.

Obesity and Fibrosis: Setting the Stage for Breast Cancer

Obesity is a rising health concern and is linked to a worsened breast cancer prognosis. Tumor desmoplasia, which is characterized by elevated numbers of cancer-associated fibroblasts and the deposition of fibrillar collagens within the stroma, may contribute to the aggressive clinical behavior of breast cancer in obesity. A major component of the breast is adipose tissue, and fibrotic changes in adipose tissue due to obesity may contribute to breast cancer development and the biology of the resulting tumors. Adipose tissue fibrosis is a consequence of obesity that has multiple sources. Adipocytes and adipose-derived stromal cells secrete extracellular matrix composed of collagen family members and matricellular proteins that are altered by obesity. Adipose tissue also becomes a site of chronic, macrophage-driven inflammation. Macrophages exist as a diverse population within obese adipose tissue and mediate the development of fibrosis through the secretion of growth factors and matricellular proteins and interactions with other stromal cells. While weight loss is recommended to resolve obesity, the long-term effects of weight loss on adipose tissue fibrosis and inflammation within breast tissue are less clear. Increased fibrosis within breast tissue may increase the risk for tumor development as well as promote characteristics associated with tumor aggressiveness.

Molecular Mechanisms of Western Diet-Induced Obesity and Obesity-Related Carcinogenesis-A Narrative Review

The present study aims to provide a narrative review of the molecular mechanisms of Western diet-induced obesity and obesity-related carcinogenesis. A literature search of the Cochrane Library, Embase and Pubmed databases, Google Scholar and the grey literature was conducted. Most of the molecular mechanisms that induce obesity are also involved in the twelve Hallmarks of Cancer, with the fundamental process being the consumption of a highly processed, energy-dense diet and the deposition of fat in white adipose tissue and the liver. The generation of crown-like structures, with macrophages surrounding senescent or necrotic adipocytes or hepatocytes, leads to a perpetual state of chronic inflammation, oxidative stress, hyperinsulinaemia, aromatase activity, activation of oncogenic pathways and loss of normal homeostasis. Metabolic reprogramming, epithelial mesenchymal transition, HIF-1α signalling, angiogenesis and loss of normal host immune-surveillance are particularly important. Obesity-associated carcinogenesis is closely related to metabolic syndrome, hypoxia, visceral adipose tissue dysfunction, oestrogen synthesis and detrimental cytokine, adipokine and exosomal miRNA release. This is particularly important in the pathogenesis of oestrogen-sensitive cancers, including breast, endometrial, ovarian and thyroid cancer, but also 'non-hormonal' obesity-associated cancers such as cardio-oesophageal, colorectal, renal, pancreatic, gallbladder and hepatocellular adenocarcinoma. Effective weight loss interventions may improve the future incidence of overall and obesity-associated cancer.

Obesity, the Adipose Organ and Cancer in Humans: Association or Causation?

Epidemiological observations, experimental studies and clinical data show that obesity is associated with a higher risk of developing different types of cancer; however, proof of a cause-effect relationship that meets the causality criteria is still lacking. Several data suggest that the adipose organ could be the protagonist in this crosstalk. In particular, the adipose tissue (AT) alterations occurring in obesity parallel some tumour behaviours, such as their theoretically unlimited expandability, infiltration capacity, angiogenesis regulation, local and systemic inflammation and changes to the immunometabolism and secretome. Moreover, AT and cancer share similar morpho-functional units which regulate tissue expansion: the adiponiche and tumour-niche, respectively. Through direct and indirect interactions involving different cellular types and molecular mechanisms, the obesity-altered adiponiche contributes to cancer development, progression, metastasis and chemoresistance. Moreover, modifications to the gut microbiome and circadian rhythm disruption also play important roles. Clinical studies clearly demonstrate that weight loss is associated with a decreased risk of developing obesity-related cancers, matching the reverse-causality criteria and providing a causality correlation between the two variables. Here, we provide an overview of the methodological, epidemiological and pathophysiological aspects, with a special focus on clinical implications for cancer risk and prognosis and potential therapeutic interventions.

Systematic Review and Meta-Analysis of the Impact of Bariatric Surgery on Future Cancer Risk

The study aimed to perform a systematic review and meta-analysis of the evidence for the prevention of future cancers following bariatric surgery. A systematic literature search of the Cochrane Library, Embase, Scopus, Web of Science and PubMed databases (2007–2023), Google Scholar and grey literature was conducted. A meta-analysis was performed using the inverse variance method and random effects model. Thirty-two studies involving patients with obesity who received bariatric surgery and control patients who were managed with conventional treatment were included. The meta-analysis suggested bariatric surgery was associated with a reduced overall incidence of cancer (RR 0.62, 95% CI 0.46–0.84, p < 0.002), obesity-related cancer (RR 0.59, 95% CI 0.39–0.90, p = 0.01) and cancer-associated mortality (RR 0.51, 95% CI 0.42–0.62, p < 0.00001). In specific cancers, bariatric surgery was associated with reduction in the future incidence of hepatocellular carcinoma (RR 0.35, 95% CI 0.22–0.55, p < 0.00001), colorectal cancer (RR 0.63, CI 0.50–0.81, p = 0.0002), pancreatic cancer (RR 0.52, 95% CI 0.29–0.93, p = 0.03) and gallbladder cancer (RR 0.41, 95% CI 0.18–0.96, p = 0.04), as well as female specific cancers, including breast cancer (RR 0.56, 95% CI 0.44–0.71, p < 0.00001), endometrial cancer (RR 0.38, 95% CI 0.26–0.55, p < 0.00001) and ovarian cancer (RR 0.45, 95% CI 0.31–0.64, p < 0.0001). There was no significant reduction in the incidence of oesophageal, gastric, thyroid, kidney, prostate cancer or multiple myeloma after bariatric surgery as compared to patients with morbid obesity who did not have bariatric surgery. Obesity-associated carcinogenesis is closely related to metabolic syndrome; visceral adipose dysfunction; aromatase activity and detrimental cytokine, adipokine and exosomal miRNA release. Bariatric surgery results in long-term weight loss in morbidly obese patients and improves metabolic syndrome. Bariatric surgery may decrease future overall cancer incidence and mortality, including the incidence of seven obesity-related cancers.

What is currently known about the association between bariatric surgery and cancer

BACKGROUND

Obesity increases the risk of multiple cancers.

OBJECTIVE

The purpose of this manuscript is to review the high-quality studies that have provided the most compelling evidence around the association between bariatric surgery and cancer risk.

SETTING

Literature review.

METHODS

The literature was reviewed for large high quality observational studies with well matched controls. Identified studies were summarized in this review.

RESULTS

Four large cohort studies were identified and summarized including the Swedish Obese Subjects study, the Utah cohorts, the Kaiser Permanente studies and the SPLENDID study. All four cohorts demonstrated a strong association between bariatric surgery and a reduction in cancer risk. Two of the cohorts showed a reduction in cancer related mortality, and two of the cohorts found a dose-response between amount of weight loss following bariatric surgery and cancer risk.

CONCLUSIONS

The evidence that bariatric surgery is associated with a reduced risk of cancer is compelling.

Response to immune checkpoint blockade improved in pre-clinical model of breast cancer after bariatric surgery

Bariatric surgery is a sustainable weight loss approach, including vertical sleeve gastrectomy (VSG). Obesity exacerbates tumor growth, while diet-induced weight loss impairs progression. It remains unknown how bariatric surgery-induced weight loss impacts cancer progression or alters response to therapy. Using a pre-clinical model of obesity followed by VSG or diet-induced weight loss, breast cancer progression and immune checkpoint blockade therapy were investigated. Weight loss by VSG or weight-matched dietary intervention before tumor engraftment protected against obesity-exacerbated tumor progression. However, VSG was not as effective as diet in reducing tumor burden despite achieving similar weight and adiposity loss. Leptin did not associate with changes in tumor burden; however, circulating IL-6 was elevated in VSG mice. Uniquely, VSG tumors displayed elevated inflammation and immune checkpoint ligand PD-L1+ myeloid and non-immune cells. VSG tumors also had reduced T lymphocytes and markers of cytolysis, suggesting an ineffective anti-tumor microenvironment which prompted investigation of immune checkpoint blockade. While obese mice were resistant to immune checkpoint blockade, anti-PD-L1 potently impaired tumor progression after VSG through improved anti-tumor immunity. Thus, in formerly obese mice, surgical weight loss followed by immunotherapy reduced breast cancer burden. Finally, we compared transcriptomic changes in adipose tissue after bariatric surgery from patients and mouse models. A conserved bariatric surgery-associated weight loss signature (BSAS) was identified which significantly associated with decreased tumor volume. Findings demonstrate conserved impacts of obesity and bariatric surgery-induced weight loss pathways associated with breast cancer progression.

As the number of people classified as obese rises globally, so do obesity-related health risks. Studies show that people diagnosed with obesity have inflammation that contributes to tumor growth and their immune system is worse at detecting cancer cells. But weight loss is not currently used as a strategy for preventing or treating cancer.

Surgical procedures for weight loss, also known as ‘bariatric surgeries’, are becoming increasingly popular. Recent studies have shown that individuals who lose weight after these treatments have a reduced risk of developing tumors. But how bariatric surgery directly impacts cancer progression has not been well studied: does it slow tumor growth or boost the anti-tumor immune response?

To answer these questions, Sipe et al. compared breast tumor growth in groups of laboratory mice that were obese due to being fed a high fat diet. The first group of mice lost weight after undergoing a bariatric surgery in which part of their stomach was removed. The second lost the same amount of weight but after receiving a restricted diet, and the third underwent a fake surgery and did not lose any weight. The experiments found that surgical weight loss cuts breast cancer tumor growth in half compared with obese mice. But mice who lost the same amount of weight through dietary restrictions had even less tumor growth than surgically treated mice.

The surgically treated mice who lost weight had more inflammation than mice in the two other groups, and had increased amounts of proteins and cells that block the immune response to tumors. Giving the surgically treated mice a drug that enhances the immune system’s ability to detect and destroy cancer cells reduced inflammation and helped shrink the mice’s tumors. Finally, Sipe et al. identified 54 genes which were turned on or off after bariatric surgery in both mice and humans, 11 of which were linked with tumor size.

These findings provide crucial new information about how bariatric surgery can impact cancer progression. Future studies could potentially use the conserved genes identified by Sipe et al. to develop new ways to stimulate the anti-cancer benefits of weight loss without surgery.

The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment

The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.

The role of obesity and bariatric surgery-induced weight loss in breast cancer

Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.

Effects of sustained weight loss on outcomes associated with obesity comorbidities and healthcare resource utilization

Objective

Determine the impact of long-term non-surgical weight loss maintenance on clinical relevance for osteoarthritis, cancer, opioid use, and depression/anxiety and healthcare resource utilization.

Methods

A cohort of adults receiving primary care within Geisinger Health System between 2001–2017 was retrospectively studied. Patients with ≥3 weight measurements in the two-year index period and obesity at baseline (BMI ≥30 kg/m²) were categorized: Obesity Maintainers (reference group) maintained weight within +/-3%; Weight Loss Rebounders lost ≥5% body weight in year one, regaining ≥20% of weight loss in year two; Weight Loss Maintainers lost ≥5% body weight in year one, maintaining ≥80% of weight loss. Association with development of osteoarthritis, cancer, opioid use, and depression/anxiety, was assessed; healthcare resource utilization was quantified. Magnitude of weight loss among maintainers was evaluated for impact on health outcomes.

Results

In total, 63,567 patients were analyzed including 67% Obesity Maintainers, 19% Weight Loss Rebounders, and 14% Weight Loss Maintainers; median follow-up was 9.7 years. Time until osteoarthritis onset was delayed for Weight Loss Maintainers compared to Obesity Maintainers (Logrank test p <0.0001). Female Weight Loss Maintainers had a 19% and 24% lower risk of developing any cancer (p = 0.0022) or obesity-related cancer (p = 0.0021), respectively. No significant trends were observed for opioid use. Weight loss Rebounders and Maintainers had increased risk (14% and 25%) of future treatment for anxiety/depression (both <0.0001). Weight loss maintenance of >15% weight loss was associated with the greatest decrease in incident osteoarthritis. Healthcare resource utilization was significantly higher for Weight Loss Rebounders and Maintainers compared to Obesity Maintainers. Increased weight loss among Weight Loss Maintainers trended with lower overall healthcare resource utilization, except for hospitalizations.

Conclusions

In people with obesity, sustained weight loss was associated with greater clinical benefits than regained short-term weight loss and obesity maintenance. Higher weight loss magnitudes were associated with delayed onset of osteoarthritis and led to decreased healthcare utilization.

Obesity and Roux-en-Y gastric bypass drive changes in miR-31 and miR-215 expression in the human rectal mucosa

Background/Objectives

Obesity increases colorectal cancer (CRC) risk. However, the effects of weight loss on CRC risk are unclear. Epigenetic mechanisms involving microRNAs that lead to dysregulated gene expression may mediate the effects of obesity and weight loss on CRC risk. We examined the effects of obesity and weight loss following Roux-en-Y gastric bypass (RYGB) on microRNA expression in the human rectal mucosa.

Subjects/Methods

We collected rectal mucosal biopsies from obese patients (n = 22) listed for RYGB and age- and sex-matched healthy non-obese Controls (n = 20), at baseline and six months post-surgery. We quantified microRNA expression in rectal mucosal biopsies using Next Generation Sequencing and bioinformatics analysis to investigate the likely functional consequences of these epigenetic changes.

Results

Compared with non-obese individuals, obese individuals showed differential expression of 112 microRNAs (p < 0.05). At six-months post-RYGB, when mean body mass had fallen by 27 kg, 60 microRNAs were differentially expressed, compared with baseline (p < 0.05). The expression of 36 microRNAs differed significantly between both i) obese and non-obese individuals and ii) obese individuals pre- and post-RYGB. Quantitative polymerase chain reaction (qPCR) demonstrated that expression of miR-31 and miR-215 was significantly (p < 0.05) higher, 143-fold and 15-fold respectively, in obese than in non-obese individuals. Weight loss, following RYGB, reduced expression of miR-31 and miR-215 to levels comparable with Controls. These differentially expressed microRNAs are implicated in pathways linked with inflammation, obesity and cancer.

Conclusion

Our findings show, for the first time, that obesity is associated with dysregulated microRNA expression in the human rectal mucosa. Further, surgically-induced weight loss may normalise microRNA expression in this tissue.

Effect of Bariatric Surgery on Survival and Hospitalizations in Patients with Severe Obesity. A Retrospective Cohort Study

Bariatric surgery (BS) confers a survival benefit in specific subsets of patients with severe obesity; otherwise, effects on hospital admissions are still uncertain. We assessed the long-term effect on mortality and on hospitalization of BS in patients with severe obesity. This was a retrospective cohort study, including all patients residing in Piedmont (age 18-60 years, BMI ≥ 40 kg/m²) admitted during 2002-2018 to the Istituto Auxologico Italiano. Adjusted hazard ratios (HR) for BS were estimated for mortality and hospitalization, considering surgery as a time-varying variable. Out of 2285 patients, 331 (14.5%) underwent BS; 64.4% received sleeve gastrectomy (SG), 18.7% Roux-en-Y gastric bypass (RYGB), and 16.9% adjustable gastric banding (AGB). After 10-year follow-up, 10 (3%) and 233 (12%) patients from BS and non-BS groups died, respectively (HR = 0.52; 95% CI 0.27-0.98, by a multivariable Cox proportional-hazards regression model). In patients undergoing SG or RYGB, the hospitalization probability decreased significantly in the after-BS group (HR = 0.77; 0.68-0.88 and HR = 0.78; 0.63-0.98, respectively) compared to non-BS group. When comparing hospitalization risk in the BS group only, a marked reduction after surgery was found for all BS types. In conclusion, BS significantly reduced the risk of all-cause mortality and hospitalization after 10-year follow-up.

Adipose Tissue-Derived Extracellular Vesicles and the Tumor Microenvironment: Revisiting the Hallmarks of Cancer

Extracellular vesicles (EVs) are crucial elements that sustain the communication between tumor cells and their microenvironment, and have emerged as a widespread mechanism of tumor formation and metastasis. In obesity, the adipose tissue becomes hypertrophic and hyperplastic, triggering increased production of pro-inflammatory adipokines, such as tumor necrosis factor α, interleukin 6, interleukin 1, and leptin. Furthermore, obese adipose tissue undergoes dysregulation in the cargo content of the released EVs, resulting in an increased content of pro-inflammatory proteins, fatty acids, and oncogenic microRNAs. These alterations drive obesity-associated inflammatory responses both locally and systemically. After being ignored for a long time, adipose tissues have recently received considerable attention as a major player in tumor microenvironment-linked obesity and cancer. The role of adipose tissue in the establishment and progression of cancer is reinforced by its high plasticity and inflammatory content. Such a relationship may be established by direct contact between adipocytes and cancer cells within the microenvironment or systemically, via EV-mediated cell-to-cell communication. Here, we highlight cues evidencing the influence of adipose tissue-derived EVs on the hallmarks of cancer, which are critical for tumor malignancy.

The Bariatric Surgery Is Associated with a Lower Incidence of Malignancy: Real World Data from Taiwan

PURPOSE

This study assessed the benefits and efficacy of bariatric surgery (BS) in reducing the risk of cancer in Asians with morbid obesity.

METHODS

Records for patients aged between 18 and 55 years whose diagnoses corresponded with the ICD-9 codes for obesity and BS were extracted from the National Health Insurance Research Database (NHIRD) in Taiwan between 2000 and 2015. The patients who underwent BS (BS group), those who did not undergo BS (NS group), and the general population (GP group) were propensity score matched. The outcome was newly diagnosed malignancy. Data were extracted from the Registry for Catastrophic Illness Patient Database (RCIPD) of the NHIRD.

RESULTS

The BS group developed significantly less malignancy (1.18%) than the GP group (1.46%, p = 0.0364). There was no statistically significant difference in malignancy risk between the BS and GP groups (aHR =1.00, p = 0.9997). The NS group developed significantly higher malignancy (2.48%) than the GP group (1.97%, p < 0.0001). There was a significantly higher malignancy risk in the NS group (aHR =1.22, p < 0.0001) than in the GP group. In the subgroup analysis, the malignancy risks of the NS group were significantly higher in the subgroup of men aged between 18 and 35 years (aHR =1.37, p = 0.003) and women aged between 18 and 35 years (aHR = 1.62, p < 0.0001), and 35-55 years (aHR = 1.27, p < 0.0001). All the subgroup analyses between the BS and GP groups demonstrated no significant differences.

CONCLUSIONS

Our study demonstrated that BS reduced the risk of malignancy in patients with morbid obesity, particularly in women and young men.

Gender Differences in Obesity-Related Cancers

PURPOSE OF REVIEW

In this review, we summarize the role of obesity in carcinogenesis, providing details on specific cancer sites. Special emphasis is given to gender differences in obesity-related cancers and on the effect of bariatric surgery on cancer risk.

RECENT FINDINGS

Accumulating evidence has highlighted the detrimental role of overweight/obesity in cancer, with almost 55% of cancers diagnosed in women and 24% diagnosed in men considered overweight- and obesity-related cancers. Sufficient data have shown that higher BMI is associated with risk of gynecologic malignancies (mainly breast and endometrial cancers) as well as cancers in sites such as the esophagus (adenocarcinoma), gastric cardia, colon, rectum, liver, gallbladder, pancreas, kidney, thyroid gland, and multiple myeloma. The main mechanisms underlying this relationship include the insulin/IGF1 system, the effect of sex hormones, and adipocytokines. Marked differences may be seen in specific cancer sites when comparing men to women. There is a higher overall incidence of obesity-related cancers among females (endometrial, ovarian, and postmenopausal female breast cancers), whereas cancers that concern both sexes show a higher incidence in males, particularly esophageal adenocarcinoma (male to female ratio: 9: 1 in the USA). Additionally, bariatric surgery has provided evidence of lowering overall cancer risk in patients with morbid obesity. Interestingly, bariatric surgery may lower overall cancer risk in women within the first 5 years after surgery due to the reduced risk of breast and endometrial cancer, and non-Hodgkin lymphoma. Obesity constitutes the base for marked metabolic, hormonal, and inflammatory alterations, including increased cancer risk in both men and women. Implementation of early obesity prevention strategies could ameliorate the continuously increasing incidence of cancer attributed to obesity.

Effects of Bariatric Surgery on Cancer Risk: Evidence from Meta-analysis

INTRODUCTION

Weight loss after bariatric surgery yields important health benefits. A multitude of observational studies have investigated the association of bariatric surgery for severe obesity with the risk of cancer. However, the results were debatable. The aim of the present study was to estimate the effect of bariatric surgery on overall cancer risk.

METHODS

A systematic literature search was performed to identify studies evaluating the association of bariatric surgery for severe obesity with the risk of cancer. Meta-analysis was performed to calculate combined prevalence.

RESULTS

Twenty-one cohort studies with 304,516 patients with obesity having under gone bariatric surgery and 8,492,408 patients with obesity as controls were included. Meta-analysis found decreased cancer risk to be associated with bariatric surgery (OR = 0.56, 95% CI = 0.48-0.66), both for the incidence of cancer (OR = 0.56, 95% CI = 0.46-0.68) and mortality of cancer (OR = 0.56, 95% CI = 0.41-0.75). In subgroup analysis, bariatric surgery was significantly associated with decreased breast cancer risk and endometrial cancer risk, but not associated with other cancer risk.

CONCLUSIONS

Our meta-analysis indicated that bariatric surgery for severe obesity was associated with decreased cancer risk, both for cancer incidence and mortality. Moreover, further studies estimating the functional effect and side effects may eventually provide a better, comprehensive understanding.

Obesity, Cancer, and Risk Reduction with Bariatric Surgery

The prevalence of noncommunicable diseases has increased dramatically in North America and throughout the world and is expected to continue increasing in coming years. Obesity has been linked to several types of cancers and is associated with increased morbidity and mortality following cancer diagnosis. Bariatric surgery has emerged as the prominent model to evaluate the effects of intentional weight loss on cancer incidence and outcomes. Current literature, comprising prospective cohort investigations, indicates site-specific reductions in cancer risk with select bariatric procedures. Future research is required to establish evidence-based indications for bariatric surgery in the context of cancer prevention.

Colorectal Cancer Risk Following Bariatric Surgery in a Nationwide Study of French Individuals With Obesity

Importance

Although bariatric surgery is effective against morbid obesity, the association of this surgery with the risk of colorectal cancer remains controversial.

Objective

To assess whether bariatric surgery is associated with altered risk of colorectal cancer among individuals with obesity.

Design, Setting, and Participants

This retrospective, population-based, multicenter, cohort study based on French electronic health data included 1 045 348 individuals with obesity, aged 50 to 75 years, and free of colorectal cancer at baseline. All inpatients with obesity having data recorded during a hospital stay between 2009 and 2018 by the French national health insurance information system database were followed up for a mean (SD) of 5.3 (2.1) years for those who did not undergo bariatric surgery and 5.7 (2.2) years for those who underwent bariatric surgery. Two groups of patients comparable in terms of age, sex, body mass index, follow-up, comorbidities, and conditions who did or did not undergo surgery were also obtained by propensity score matching.

Exposures

Bariatric surgery (n = 74 131), including adjustable gastric banding, sleeve gastrectomy, gastric bypass; or no bariatric surgery (n = 971 217).

Main Outcomes and Measures

Primary outcome was incident colorectal cancer. Standardized incidence ratios were calculated using age-, sex-, and calendar year-matched colorectal cancer incidence among the general French population during the corresponding years. Secondary outcome was incident colorectal benign polyps.

Results

Among a total of 1 045 348 patients, the mean (SD) age was 57.3 (5.5) years for the 74 131 patients in the surgical cohort vs 63.4 (7.0) years for the 971 217 patients in the nonsurgical cohort. The mean (SD) follow-up was 6.2 (2.1) years for patients who underwent adjustable gastric banding, 5.5 (2.1) years for patients who underwent sleeve gastrectomy, and 5.7 (2.2) years for patients who underwent gastric bypass. In total, 13 052 incident colorectal cancers (1.2%) and 63 649 colorectal benign polyps were diagnosed. The rate of colorectal cancer was 0.6% in the bariatric surgery cohort and 1.3% in the cohort without bariatric surgery. In the latter cohort, 9417 cases were expected vs 12 629 observed, a standardized incidence ratio of 1.34 (95% CI, 1.32-1.36). In the bariatric surgery cohort, 428 cases were expected and 423 observed, a standardized incidence ratio of 1.0 (95% CI, 0.90-1.09). Propensity score-matched hazard ratios in comparable operated vs nonoperated groups were 0.68 (95% CI, 0.60-0.77) for colorectal cancer and 0.56 (95% CI, 0.53-0.59) for colorectal benign polyp. There were fewer new diagnoses of colorectal cancer after gastric bypass (123 of 22 343 [0.5%]) and sleeve gastrectomy (185 of 35 328 [0.5%]) than after adjustable gastric banding (115 of 16 460 [0.7%]), and more colorectal benign polyps after adjustable gastric banding (775 of 15 647 [5.0%]) than after gastric bypass (639 of 20 863 [3.1%]) or sleeve gastrectomy (1005 of 32 680 [3.1%]).

Conclusion and Relevance

The results of this nationwide cohort study suggested that following bariatric surgery, patients with obesity share the same risk of colorectal cancer as the general population, whereas for patients with obesity who do not undergo bariatric surgery, the risk is 34% above that of the general population.

Investigating Bias from Missing Data in an Electronic Health Records-Based Study of Weight Loss After Bariatric Surgery

PURPOSE

Missing data is common in electronic health records (EHR)-based obesity research. To avoid bias, it is critical to understand mechanisms that underpin missingness. We conducted a survey among bariatric surgery patients in three integrated health systems to (i) investigate predictors of disenrollment and (ii) examine differences in weight between disenrollees and enrollees at 5 years.

MATERIALS AND METHODS

We identified 2883 patients who had bariatric surgery between 11/2013 and 08/2014. Patients who disenrolled before their 5-year anniversary were invited to participate in a survey to ascertain reasons for disenrollment and current weight. Logistic regression was used to investigate predictors of disenrollment. Five-year percent weight change distributions were estimated using inverse-probability weighting to adjust for (un)availability of EHR weight data at 5 years among enrollees and survey (non-)response among disenrollees.

RESULTS

Among 536 disenrolled patients, 104 (19%) completed the survey. Among 2347 patients who maintained enrollment, 384 (16%) had no weight measurement in the EHR near 5 years. Insurance, age, Hispanic ethnicity, and site predicted disenrollment. Disenrollees had slightly greater weight loss than enrollees.

CONCLUSION

We found little evidence of weight loss differences by enrollment status. Collecting information through surveys can be an effective tool to investigate and adjust for missingness in EHR-based studies.

Obesity in Gynecologic Oncology

The decades-long global obesity epidemic has resulted in steady increase in the incidence of obesity-related malignancies. The associated diagnostic and therapeutic implications present a clinical challenge for gynecologic oncology treatment strategies. Recent studies have provided solid evidence for an independent, linear, positive correlation between a pathologically increased body mass index and the probability of developing endometrial or postmenopausal breast cancer. The pathogenesis is complex and the subject of current research. Proposed causes include pathologically increased serum levels of sexual steroids and adiponectin, obesity-induced insulin resistance, and systemic inflammatory processes. The scientific evidence for an association between obesity and other gynecological malignancies is, however, less solid. The clinical relevance of obesity as a risk factor for epithelial ovarian cancer, cervical cancer and vulvar cancer appears to be negligible. Nevertheless, obesity appears to have a negative impact on prognosis and oncologic outcomes for all gynecological cancers. Whether or not this effect can be interpreted as correlative or causal is still a subject of ongoing debate.

Bariatric Surgery is Associated With Reduced Risk of Breast Cancer in Both Premenopausal and Postmenopausal Women

OBJECTIVE

This retrospective cohort study examined whether bariatric surgery is associated with reduced risk of breast cancer among pre- and postmenopausal women.

BACKGROUND

Obesity is associated with increased risk of breast cancer, but the impact of weight loss on breast cancer risk has been difficult to quantify.

METHODS

The cohort included obese (body mass index ≥35 kg/m) patients enrolled in an integrated health care delivery system between 2005 and 2012 (with follow-up through 2014). Female bariatric surgery patients (N = 17,998) were matched on body mass index, age, study site, and comorbidity index to 53,889 women with no bariatric surgery. Kaplan-Meier curves and Cox proportional hazards models were used to examine incident breast cancer up to 10 years after bariatric surgery. Pre- and postmenopausal women were examined separately, and further classified by estrogen receptor (ER) status.

RESULTS

The analysis included 301 premenopausal and 399 postmenopausal breast cancer cases. In multivariable adjusted models, bariatric surgery was associated with a reduced risk of both premenopausal (HR = 0.72, 95% CI, 0.54-0.94) and postmenopausal (HR = 0.55, 95% CI, 0.42-0.72) breast cancer. Among premenopausal women, the effect of bariatric surgery was more pronounced among ER-negative cases (HR = 0.36, 95% CI, 0.16-0.79). Among postmenopausal women, the effect was more pronounced in ER-positive cases (HR = 0.52, 95% CI, 0.39-0.70).

CONCLUSIONS

Bariatric surgery was associated with a reduced risk of breast cancer among severely obese women. These findings have significant public health relevance because the prevalence of obesity continues to rise, and few modifiable breast cancer risk factors have been identified, especially for premenopausal women.

Outcomes in Bariatric and Metabolic Surgery: an Updated 5-Year Review

PURPOSE OF REVIEW

Knowledge regarding postoperative outcomes after bariatric and metabolic surgery continues to evolve. This review highlights key findings in outcomes research over the last 5 years related to weight loss, remission of obesity-related disease, reflux, revisional surgery, robotic-assisted surgical platforms, and adolescent populations.

RECENT FINDINGS

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) produce similar weight loss patterns at 5 years, while duodenal switch (BPD/DS) and related procedures are associated with maximal weight loss overall and optimal resolution of obesity-related comorbidities. Remission of type 2 diabetes mellitus (T2DM) following surgery is more likely in patients who are not insulin dependent prior to surgery. Bariatric and metabolic surgery offers a significant protective effect against coronary artery disease (CAD) and associated interventions in both diabetic and nondiabetic patients, as well as heart failure (HF). Gastroesophageal reflux disease (GERD) and dysphagia following SG are common, and routine endoscopic surveillance for Barrett's esophagus may be of significant utility. Robotic-assisted laparoscopic platforms concur similar outcomes to laparoscopic intervention, with a potential benefit in high BMI patients. Revisional surgery is most commonly performed for weight regain and/or inadequate weight loss following an index procedure, or reflux, and generally characterized by higher postoperative complication rates and longer inpatient lengths of stay (LOS). Surgical intervention in adolescent populations has similar weight loss and postoperative complication profiles to those seen in adult populations, with improved outcomes related to T2DM. Bariatric and metabolic surgery continues to evolve as a treatment for obesity and obesity-related comorbidities. While effective for weight loss and remission of obesity-related disease, SG is associated with high rates of postoperative GERD.

Impact of physical activity and energy restriction on immune regulation of cancer

Cancer is a major public health issue worldwide. Lifestyle factors, such as body weight and physical activity (PA), significantly impact cancer risk and progression. There is strong evidence that PA reduces and obesity increases risk and mortality from numerous cancer types. Energy restriction (ER) in non-obese hosts significantly reduces tumor incidence in a variety of preclinical models, and reduces body weight and cardiometabolic risk factors in humans. Emerging data suggest that PA- and ER-induced changes in inflammatory and immune mediators may contribute to the cancer prevention effects of these interventions. A systematic literature search was conducted to identify studies that evaluated the impact of PA and ER on tumor and immune outcomes in humans and animal models. A total of 97 eligible studies were identified (68 studies reporting PA interventions and 30 studies reporting ER interventions). Thirty-one studies investigated the effect of PA on cancer immune outcomes using preclinical cancer models of breast (n=17, 55%), gastrointestinal (n=6, 19%), melanoma (n=4, 13%), and several other cancer types (n=4, 13%). Despite the heterogeneity in study designs, the majority of studies (n=23, 74%) reported positive effects of PA on tumor outcomes. Thirty-seven clinical studies investigated the effect of PA on cancer immune outcomes. None reported tumor outcomes, thus only immune outcomes were evaluated in these studies. PA studies were conducted in patients with breast (n=22, 59%), gastrointestinal (n=5, 14%), prostate (n=2, 5%), esophageal (n=1, 3%), lung (n=1, 3%) cancer, leukemia (n=1, 3%), or mixed cancer types (n=5, 14%). Twenty-two studies investigated the effect of ER interventions on cancer immune outcomes using preclinical cancer models including breast (n=5, 23%), gastrointestinal (n=5, 23%), lung (n=2, 9%), liver (n=2, 9%), pancreatic (n=2, 9%), and several other cancer types (n=6, 27%). Positive effects of ER on tumor outcomes were reported in 21 of 22 studies. Six clinical studies investigated the effect of ER (in combination with PA) on tumor immune outcomes in cancer patients with overweight or obesity. Five were conducted in breast cancer patients, and one recruited patients of a mix of cancer types. A wide range of immunological parameters including immune cell phenotype and function, cytokines, and other immune and inflammatory markers were assessed in multiple tissue compartments (blood, spleen, lymph nodes and tumor) in the included studies. Results from preclinical and clinical studies suggest that both PA and ER exert heterogeneous effects on circulating factors and systemic immune responses. PA + ER alters the gene expression profile and immune infiltrates in the tumor which may result in a reduction in immune suppressive factors. However, additional studies are needed to better understand the effect of PA and/or ER on immunomodulation, particularly in the tumor microenvironment (TME).

Bariatric surgery decreases the number of first-time hospital admissions for cancer in severely obese patients. A retrospective analysis of the National Inpatient Sample database

BACKGROUND

According to the U.S. Centers for Disease Control, cancers linked to overweight or obesity accounted for roughly 40% of all U.S. malignancies in 2014.

OBJECTIVES

The primary aim of this epidemiologic study was to assess whether bariatric surgery might have any preventative role against obesity-linked cancers among individuals with obesity.

SETTING

Hospitals across the United States participating in the National Inpatient Sample database, created, updated, and monitored by the U.S. Healthcare Cost and Utilization Project.

METHODS

National Inpatient Sample data collected from 2010 to 2014 were examined to identify any difference in the number of first cancer-related hospitalizations, as a proxy for cancer incidence, between patients with a history of prior bariatric surgery (cases) and those without (controls). Patients with any prior cancer diagnosis were excluded. To match the body mass index ≥35 kg/m² generally required for bariatric surgery, all controls had to have a body mass index ≥35 kg/m². International Classification of Diseases-9 codes were employed to identify admissions for 13 obesity-linked cancers. Multivariate logistic regression analysis was performed to identify any case-control differences, after matching for all baseline demographic, co-morbidity, and cancer risk-factor variables. All percentages and means (with confidence intervals) were weighted, per Healthcare Cost and Utilization Project guidelines.

RESULTS

Among 1,590,579 controls and 247,015 bariatric surgery cases, there were 29,822 (1.93%; 95% confidence interval 1.91-1.96) and 3540 (1.43%; 1.38-1.47) first hospitalizations for cancer (adjusted odds ratio 1.17; 1.13-1.23; P < .0001).

CONCLUSIONS

Preliminary findings from a large U.S. database suggest that bariatric surgery may reduce the incidence of cancer in patients considered at high risk because of severe obesity.

The risk of developing breast, ovarian, and endometrial cancer in obese women submitted to bariatric surgery: a meta-analysis

This article performs a systematic review and meta-analysis to investigate the impact of bariatric surgery and the risk of developing breast, ovarian, and endometrial cancer in obese women. MEDLINE, EMBASE, LILACS, and Cochrane databases were searched from inception until January 2019 to retrieve studies that assessed the risk of breast, ovarian, or endometrial cancer in obese women submitted to bariatric surgery. There was no language restriction. We extracted and combined data from studies to assess the risk ratio (RR) of developing these neoplasms. A random-effects meta-analytic model was applied in all calculations. The New Castle Ottawa and GRADE were used to assess quality of the included studies and certainty of the evidence, respectively. This study is registered in PROSPERO (CRD42019112927). We found 188 articles and 7 of those were included in our meta-analysis, which incorporated a total of 150,537 patients in the bariatric surgery arm and 1,461,938 women in the control arm. The total RR of breast, ovarian, and endometrial cancer was .41 (95% confidence interval [CI]: .31-.56]; I² = 90%; 7 studies). The risk of breast cancer was reduced by 49% (RR: .51; 95%CI: .31-.83]; I² = 92%; 6 studies). The risk of ovarian cancer was reduced by 53% (RR: .47; 95%CI: .27-81; I² = 0%; 3 studies). The risk of endometrial cancer was reduced by 67% (RR: .33; 95%CI: .21-.51; I² = 88%; 7 studies). Bariatric surgery may have a protective effect reducing the risk of breast, ovarian, and endometrial cancer in obese women. The high heterogeneity and other issues justify the need for further studies to deepen our knowledge.

Sleeve gastrectomy ameliorates endothelial function and prevents lung cancer by normalizing endothelin-1 axis in obese and diabetic rats

BACKGROUND

Previous evidence has implied that obesity is an independent risk factor for developing cancer. Being closely related to obesity, type 2 diabetes mellitus provides a suitable environment for the formation and metastasis of tumors through multiple pathways. Although bariatric surgeries are effective in preventing and lowering the risk of various types of cancer, the underlying mechanisms of this effect are not clearly elucidated.

AIM

To uncover the role and effect of sleeve gastrectomy (SG) in preventing lung cancer in obese and diabetic rats.

METHODS

SG was performed on obese and diabetic Wistar rats, and the postoperative transcriptional and translational alterations of the endothelin-1 (ET-1) axis in the lungs were compared to sham-operated obese and diabetic rats and age-matched healthy controls to assess the improvements in endothelial function and risk of developing lung cancer at the postoperative 4^th, 8^th, and 12^th weeks. The risk was also evaluated using nuclear phosphorylation of H2A histone family member X as a marker of DNA damage (double-strand break).

RESULTS

Compared to obese and diabetic sham-operated rats, SG brought a significant reduction to body weight, food intake, and fasting blood glucose while improving oral glucose tolerance and insulin sensitivity. In addition, ameliorated levels of gene and protein expression in the ET-1 axis as well as reduced DNA damage indicated improved endothelial function and a lower risk of developing lung cancer after the surgery.

CONCLUSION

Apart from eliminating metabolic disorders, SG improves endothelial function and plays a protective role in preventing lung cancer via normalized ET-1 axis and reduced DNA damage.

Cholangiocarcinoma Following Bariatric Surgery: a Prospective Follow-Up Single-Center Audit

BACKGROUND

Cholangiocarcinoma (CC) incidence is rising worldwide. Obesity and its related metabolic impairments are associated with primitive liver malignancies including CC. While bariatric surgery (BS) is associated with decreased risk of incident cancer, few data are available regarding CC incidence, presentation, and management issues after BS.

METHODS

We retrospectively reviewed collected data on 1911 consecutive patients undergoing BS from 2010 to 2019.

RESULTS

We recorded three cases (0.16%) of CC during the postoperative follow-up. All cases underwent a Roux-en-Y gastric bypass (RYGB) for class III obesity with metabolic diseases (i.e., type 2 diabetes mellitus, hypertension, dyslipidemia, and obstructive sleep apnea) without any personal or familial history of biliary disease. The patients presented with an inaugural jaundice or pruritus at 8, 12, and 13 months after RYBG, which enabled the diagnosis of metastatic CCs in all cases. In such palliative setting without access to the pancreato-biliary system, biliary drainage was ensured by a percutaneous trans-hepatic biliary drain. Chemotherapy was initiated in two patients. All the patients died within a delay of 2, 11, and 17 months after the diagnosis, respectively.

CONCLUSION

The incidence of post-BS CC appears low, but the prognosis is poor because of advanced stages at diagnosis. These cases illustrate the difficulty to make both on-time diagnosis and optimal management of CC especially in patients operated of RYGB with limited access to the excluded anatomy.

Association between weight loss and serum biomarkers with risk of incident cancer in the Longitudinal Assessment of Bariatric Surgery cohort

BACKGROUND

Bariatric surgery reduces cancer risk in populations with obesity. It is unclear if weight loss alone or metabolic changes related to bariatric surgery cause this effect.

OBJECTIVE

We evaluated the relationship between surgical weight loss and serum biomarker changes with incident cancer in a bariatric surgery cohort.

SETTING

Ten U.S. clinical facilities.

METHODS

The Longitudinal Assessment of Bariatric Surgery 2 (LABS-2) is a prospective multicenter cohort (n = 2458, 79% female, mean age = 46). We evaluated weight and serum biomarkers, measured preoperatively and 1 year postoperatively, as predictors for incident cancer. Associations were determined using Cox proportional hazards models adjusting for weight loss, age, sex, education, and smoking history.

RESULTS

Over 8759 person-years of follow-up, 82 patients reported new cancer diagnosis (936 per 100,000 person-years, 95% confidence interval [CI]: 749-1156). Cancer risk was decreased by approximately 50% in participants with 20% to 34.9% total weight loss (TWL) compared with <20% TWL (hazard ratio [HR] = .49, 95%CI: .29-.83). Reduced cancer risk was observed with percent decrease from baseline for glucose (per 10%, HR = .94, 95%CI: .90-.99), proinsulin (per 20%, HR = .95, 95%CI: .93-.98), insulin (per 30%, HR = .97, 95%CI: .96-.99), and leptin (per 20%, HR = .81, 95%CI: .68-.97), and per 15% percent increase in ghrelin (HR = .94, 95%CI: .29-.83).

CONCLUSIONS

After bariatric surgery, cancer risk is reduced >50% when weight loss exceeds 20% TWL compared with patients with <20% TWL. Weight loss alone may not explain the observed risk reduction, as improvements in diabetes, leptin, and ghrelin were associated with decreased cancer risk.

Obesity and ageing: Two sides of the same coin

Conditions and comorbidities of obesity mirror those of ageing and age-related diseases. Obesity and ageing share a similar spectrum of phenotypes such as compromised genomic integrity, impaired mitochondrial function, accumulation of intracellular macromolecules, weakened immunity, shifts in tissue and body composition, and enhanced systemic inflammation. Moreover, it has been shown that obesity reduces life expectancy by 5.8 years in men and 7.1 years in women after the age of 40. Shorter life expectancy could be because obesity holistically accelerates ageing at multiple levels. Besides jeopardizing nuclear DNA and mitochondrial DNA integrity, obesity modifies the DNA methylation pattern, which is associated with epigenetic ageing in different tissues. Additionally, other signs of ageing are seen in individuals with obesity including telomere shortening, systemic inflammation, and functional declines. This review aims to show how obesity and ageing are "two sides of the same coin" through discussing how obesity predisposes an individual to age-related conditions, illness, and disease. We will further demonstrate how the mechanisms that perpetuate the early-onset of chronic diseases in obesity parallel those of ageing.

Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures - 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPGs) was commissioned by the American Association of Clinical Endocrinologists (AACE), The Obesity Society (TOS), American Society for Metabolic and Bariatric Surgery (ASMBS), Obesity Medicine Association (OMA), and American Society of Anesthesiologists (ASA) Boards of Directors in adherence with the AACE 2017 protocol for standardized production of CPGs, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include: contextualization in an adiposity-based chronic disease complications-centric model, nuance-based and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current health care arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence based within the context of a chronic disease. A team approach to perioperative care is mandatory, with special attention to nutritional and metabolic issues.

Impact of bariatric surgery on cancer risk reduction

Obesity is second only to tobacco as a preventable cause of cancer in the US. By multifactorial and often additive mechanisms, obesity leads to the development and promotion of 40% of the cancers diagnosed in this country, including post-menopausal breast, endometrial, colorectal, kidney, liver and pancreatic cancers, among others. Though prevention of obesity should be the ultimate goal of thoughtful and effective healthcare practices, it remains a highly prevalent condition, and morbid obesity (BMI ≥40 Kg/m²) can be refractory to lifestyle interventions in many cases. Currently bariatric surgery is an effective treatment strategy for individuals who suffer from morbid obesity or obesity with associated co-morbidities and fail to lose weight under a medically supervised diet and exercise program. The current review addresses seminal studies that have investigated the potential cancer prevention effects of bariatric surgery, demonstrating a positive impact mostly in post-menopausal breast and endometrial cancers. The controversial association between bariatric surgery and increased colorectal cancer (CRC) risk is also recognized and discussed. Finally, while bariatric surgery should not be routinely recommended as a cancer prevention strategy, it has the potential to decrease the risk for certain types of cancers as a collateral beneficial effect.

Review: Diabetes, Obesity, and Cancer-Pathophysiology and Clinical Implications

Obesity and diabetes have both been associated with an increased risk of cancer. In the face of increasing obesity and diabetes rates worldwide, this is a worrying trend for cancer rates. Factors such as hyperinsulinemia, chronic inflammation, antihyperglycemic medications, and shared risk factors have all been identified as potential mechanisms underlying the relationship. The most common obesity- and diabetes-related cancers are endometrial, colorectal, and postmenopausal breast cancers. In this review, we summarize the existing evidence that describes the complex relationship between obesity, diabetes, and cancer, focusing on epidemiological and pathophysiological evidence, and also reviewing the role of antihyperglycemic agents, novel research approaches such as Mendelian Randomization, and the methodological limitations of existing research. In addition, we also describe the bidirectional relationship between diabetes and cancer with a review of the evidence summarizing the risk of diabetes following cancer treatment. We conclude this review by providing clinical implications that are relevant for caring for patients with obesity, diabetes, and cancer and provide recommendations for improving both clinical care and research for patients with these conditions.

Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures - 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPG) was commissioned by the American Association of Clinical Endocrinologists, The Obesity Society, the American Society of Metabolic and Bariatric Surgery, the Obesity Medicine Association, and the American Society of Anesthesiologists boards of directors in adherence to the American Association of Clinical Endocrinologists 2017 protocol for standardized production of CPG, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include contextualization in an adiposity-based, chronic disease complications-centric model, nuance-based, and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current healthcare arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence-based within the context of a chronic disease. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Effects of obesity and weight loss on mitochondrial structure and function and implications for colorectal cancer risk

Colorectal cancer (CRC) is the third most common cancer globally. CRC risk is increased by obesity, and by its lifestyle determinants notably physical inactivity and poor nutrition. Obesity results in increased inflammation and oxidative stress which cause genomic damage and contribute to mitochondrial dysregulation and CRC risk. The mitochondrial dysfunction associated with obesity includes abnormal mitochondrial size, morphology and reduced autophagy, mitochondrial biogenesis and expression of key mitochondrial regulators. Although there is strong evidence that increased adiposity increases CRC risk, evidence for the effects of intentional weight loss on CRC risk is much more limited. In model systems, energy depletion leads to enhanced mitochondrial integrity, capacity, function and biogenesis but the effects of obesity and weight loss on mitochondria in the human colon are not known. We are using weight loss following bariatric surgery to investigate the effects of altered adiposity on mitochondrial structure and function in human colonocytes. In summary, there is strong and consistent evidence in model systems and more limited evidence in human subjects that over-feeding and/or obesity result in mitochondrial dysfunction and that weight loss might mitigate or reverse some of these effects.

The Impact of the Adipose Organ Plasticity on Inflammation and Cancer Progression

Obesity is characterized by chronic and low-grade systemic inflammation, an increase of adipose tissue, hypertrophy, and hyperplasia of adipocytes. Adipose tissues can be classified into white, brown, beige and pink adipose tissues, which display different regulatory, morphological and functional characteristics of their adipocyte and immune cells. Brown and white adipocytes can play a key role not only in the control of energy homeostasis, or through the balance between energy storage and expenditure, but also by the modulation of immune and inflammatory responses. Therefore, brown and white adipocytes can orchestrate important immunological crosstalk that may deeply impact the tumor microenvironment and be crucial for cancer establishment and progression. Recent works have indicated that white adipose tissues can undergo a process called browning, in which an inducible brown adipocyte develops. In this review, we depict the mechanisms involved in the differential role of brown, white and pink adipocytes, highlighting their structural, morphological, regulatory and functional characteristics and correlation with cancer predisposition, establishment, and progression. We also discuss the impact of the increased adiposity in the inflammatory and immunological modulation. Moreover, we focused on the plasticity of adipocytes, describing the molecules produced and secreted by those cells, the modulation of the signaling pathways involved in the browning phenomena of white adipose tissue and its impact on inflammation and cancer.

Surgical management of obesity

Weight loss surgery is the most effective intervention for addressing obesity and related metabolic disorders such as diabetes. We describe common surgical procedures as well as emerging and investigational procedures in terms of their capacity to induce weight reduction and their risk profiles. We then discuss the impact of weight loss surgery on important obesity related disorders including diabetes, cardiovascular disease, and non-alcoholic fatty liver disease. The question of operative choice is discussed with respect to benefits and risks of common procedures. Reoperative weight loss surgery, an increasingly common element of weight loss surgical practice, is reviewed. We briefly discuss the metabolic mechanism of action of weight loss surgery. Lack of access to and under-utilization of weight loss surgery represent important challenges to adequate obesity treatment, and we review these topics as well.

Surgical treatment of obesity

Obesity prevalence continues to increase worldwide, as do the numerous chronic diseases associated with obesity, including diabetes, non-alcoholic fatty liver disease, dyslipidemia, and hypertension. The prevalence of bariatric surgery also continues to increase and remains the most effective and sustainable treatment for obesity. Over the last several years, numerous prospective and longitudinal studies have demonstrated the benefits of bariatric surgery on weight loss, mortality, and other chronic diseases. Even though the mechanisms underlying many of these beneficial effects remain poorly understood, surgical management of obesity continues to increase given its unmatched efficacy. In this commentary, we discuss recent clinical advancements as well as several areas needed for future research, including indications for bariatric and metabolic surgery, determination of responders and non-responders, metabolic surgery in non-obese individuals, and the evolving role of bariatric surgery in adolescents.

Cancer as a Matter of Fat: The Crosstalk between Adipose Tissue and Tumors

Obesity has been linked to the increased risk and aggressiveness of many types of carcinoma. A state of chronic inflammation in adipose tissue (AT), resulting in genotoxic stress, may contribute to carcinogenesis and cancer initiation. Evidence that AT plays a role in cancer aggressiveness is solid and mounting. During cancer progression, tumor cells engage in a metabolic symbiosis with adjacent AT. Mature adipocytes provide adipokines and lipids to cancer cells, while stromal and immune cells from AT infiltrate carcinomas and locally secrete paracrine factors within the tumor microenvironment. This review focuses on the crosstalk between AT and tumor cells that promotes tumor growth and increases cellular lipid metabolism, metastasis, and chemoresistance.