Differential molecular changes in patients with asymptomatic long-segment Barrett's esophagus treated by antireflux surgery or medical therapy

Surgical treatment of GERD: systematic review and meta-analysis

BACKGROUND

Gastroesophageal reflux disease (GERD) has a high worldwide prevalence in adults and children. There is uncertainty regarding medical versus surgical therapy and different surgical techniques. This review assessed outcomes of antireflux surgery versus medical management of GERD in adults and children, robotic versus laparoscopic fundoplication, complete versus partial fundoplication, and minimal versus maximal dissection in pediatric patients.

METHODS

PubMed, Embase, and Cochrane databases were searched (2004-2019) to identify randomized control and non-randomized comparative studies. Two independent reviewers screened for eligibility. Random effects meta-analysis was performed on comparative data. Study quality was assessed using the Cochrane Risk of Bias and Newcastle Ottawa Scale.

RESULTS

From 1473 records, 105 studies were included. Most had high or uncertain risk of bias. Analysis demonstrated that anti-reflux surgery was associated with superior short-term quality of life compared to PPI (Std mean difference =  - 0.51, 95%CI  - 0.63, - 0.40, I² = 0%) however short-term symptom control was not significantly superior (RR = 0.75, 95%CI 0.47, 1.21, I² = 82%). A proportion of patients undergoing operative treatment continue PPI treatment (28%). Robotic and laparoscopic fundoplication outcomes were similar. Compared to total fundoplication, partial fundoplication was associated with higher rates of prolonged PPI usage (RR = 2.06, 95%CI 1.08, 3.94, I² = 45%). There was no statistically significant difference for long-term symptom control (RR = 0.94, 95%CI 0.85, 1.04, I² = 53%) or long-term dysphagia (RR = 0.73, 95%CI 0.52, 1.02, I² = 0%). Ien, minimal dissection during fundoplication was associated with lower reoperation rates than maximal dissection (RR = 0.21, 95%CI 0.06, 0.67).

CONCLUSIONS

The available evidence regarding the optimal treatment of GERD often suffers from high risk of bias. Additional high-quality randomized control trials may further inform surgical decision making in the treatment of GERD.

NF-κB signaling and crosstalk during carcinogenesis

Transcription factors (TFs) are proteins that control the transcription of genetic information from DNA to mRNA by binding to specific DNA sequences either on their own or with other proteins as a complex. TFs thus support or suppress the recruitment of the corresponding RNA polymerase. In general, TFs are classified by structure or function. The TF, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), is expressed in all cell types and tissues. NF-κB signaling and crosstalk are involved in several steps of carcinogenesis including in sequences involving pathogenic stimulus, chronic inflammation, fibrosis, establishment of its remodeling to the precancerous niche (PCN) and transition of a normal cell to a cancer cell. Triggered by various inflammatory cytokines, NF-κB is activated along with other TFs with subsequent stimulation of cell proliferation and inhibition of apoptosis. The involvement of NF-κB in carcinogenesis provides an opportunity to develop anti-NF-κB therapies. The complexity of these interactions requires that we elucidate those aspects of NF-κB interactions that play a role in carcinogenesis, the sequence of events leading to cancer.

Acid suppression and surgical therapy for Barrett's oesophagus

Gastro-oesophageal reflux disease is a common medical problem in developed countries, and is a risk factor for the development of Barrett's oesophagus and oesophageal adenocarcinoma. Both proton pump inhibitor therapy and antireflux surgery are effective at controlling endoscopic signs and symptoms of gastro-oesophageal reflux in patients with Barrett's oesophagus, but often fail to eliminate pathological oesophageal acid exposure. The current available studies strongly suggest that acid suppressive therapy, both pharmacological as well as surgical acid suppression, can reduce the risk the development and progression in patients with Barrett's oesophagus, but are not capable of complete prevention. No significant differences have been found between pharmacological and surgical therapy. For clinical practice, patients should be prescribed a proton pump inhibitor once daily as maintenance therapy, with the dose guided by symptoms. Antireflux surgery can be a good alternative to proton pump inhibitor therapy, but should be primarily offered to patients with symptomatic reflux, and not to asymptomatic patients with the rationale to protect against cancer.

Strategies to improve outcomes in esophageal adenocarcinoma

Esophageal adenocarcinoma is one of the fastest rising cancers in Western society. Incidence has increased by 600% within the last 30 years. Rates of diagnosis and death run parallel due to the poor prognosis and a lack of effective treatments. Potentially curative treatments are followed by high rates of disease recurrence. For the majority of patients, who present with advanced disease, we have no effective treatment. We discuss the key areas of progress in this demanding field and offer our views on the direction of future research and treatment.

The esophagitis to adenocarcinoma sequence; the role of inflammation

Esophageal adenocarcinoma (EAC) is the eighth most common cancer worldwide, and approximately 15% of patients survive 5years. Reflux disease (GERD) and Barrett's esophagus (BE) are major risk factors for the development of EAC, and epidemiologic studies highlight a strong association with obesity. The immune, inflammatory and intracellular signaling changes resulting from chronic inflammation of the esophageal squamous epithelium are increasingly well characterized. In GERD and Barrett's, an essential role for T-cells in the initiation of inflammation in the esophagus has been identified, and a balance between T-cell responses and phenotype may play an important role in disease progression. Obesity is a chronic low-grade inflammatory state, fueled by adipose tissue derived- inflammatory mediators such as IL-6, TNF-α and leptin, representing a novel area for targeted research. Additionally, reactive oxygen species (ROS) and receptor tyrosine kinase (RTK) activation may drive progression from esophagitis to EAC, and downstream signaling pathways employed by these molecules may be important. This review will explain the diverse range of mechanisms potentially driving and maintaining inflammation within the esophagus and explore both existing and future therapeutic strategies targeting the process.

Clinical issues in oesophageal adenocarcinoma: could DNA copy number hold the key?

While not being considered a common cancer, since 1975 oesophageal adenocarcinoma (OAC) has had the fastest-rising incidence of any malignancy in Caucasian Western populations. In the absence of major improvements in treatment since this rise began, the number of deaths has also increased rapidly. In contrast, there have been significant advances in basic science in this period. One such advance is the discovery of DNA copy number aberrations (CNAs), and their potential role in carcinogenesis. The study of CNAs offers the potential to answer fundamental clinical questions in OAC, which in turn may lead to improved diagnosis, staging and treatment. This review outlines current clinical dilemmas in OAC, discusses the role that CNAs have been shown to play to date and highlights potential future applications.

The role of CXC chemokines in the transition of chronic inflammation to esophageal and gastric cancer

Chronic inflammation may increase the risk to develop cancer, for instance esophagitis or gastritis may lead to development of esophageal or gastric cancer, respectively. The key molecules attracting leukocytes to local inflammatory sites are chemokines. We here provide a systematic review on the impact of CXC chemokines (binding the receptors CXCR1, CXCR2, CXCR3 and CXCR4) on the transition of chronic inflammation in the upper gastrointestinal tract to neoplasia. CXCR2 ligands, including GRO-α,β,γ/CXCL1,2,3, ENA-78/CXCL5 and IL-8/CXCL8 chemoattract pro-tumoral neutrophils. In addition, angiogenic CXCR2 ligands stimulate the formation of new blood vessels, facilitating tumor progression. The CXCR4 ligand SDF-1/CXCL12 also promotes tumor development by stimulating angiogenesis and by favoring metastasis of CXCR4-positive tumor cells to distant organs producing SDF-1/CXCL12. Furthermore, these angiogenic chemokines also directly enhance tumor cell survival and proliferation. In contrast, the CXCR3 ligands Mig/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11 are angiostatic and attract anti-tumoral T lymphocytes and may therefore mediate tumor growth retardation and regression. Thus, chemokines exert diverging, sometimes dual roles in tumor biology as described for esophageal and gastric cancer. Therefore extensive research is needed to completely unravel the complex chemokine code in specific cancers. Possibly, chemokine-targeted cancer therapy will have to be adapted to the individual's chemokine profile.

MicroRNA-196a & microRNA-101 expression in Barrett's oesophagus in patients with medically and surgically treated gastro-oesophageal reflux

Background

Proton pump inhibitor (PPI) medication and surgical fundoplication are used for the control of gastro-oesophageal reflux in patients with Barrett's oesophagus, but differ in their effectiveness for both acid and bile reflux. This might impact on the inflammatory processes that are associated with progression of Barrett's oesophagus to cancer, and this may be evident in the gene expression profile and microRNA expression pattern in Barrett's oesophagus mucosa. We hypothesised that two miRNAs with inflammatory and oncogenic roles, miR-101 and miR-196a, are differentially expressed in Barrett's oesophagus epithelium in patients with reflux treated medically vs. surgically.

Findings

Mucosal tissue was obtained at endoscopy from patients with Barrett's oesophagus whose reflux was controlled by proton pump inhibitor (PPI) therapy (n = 20) or by fundoplication (n = 19). RNA was extracted and the expression of miR-101 and miR-196a was measured using real-time reverse transcription - polymerase chain reaction. There were no significant differences in miR-101 and miR-196a expression in Barrett's oesophagus epithelium in patients treated by PPI vs. fundoplication (p = 0.768 and 0.211 respectively). Secondary analysis showed a correlation between miR-196a expression and Barrett's oesophagus segment length (p = 0.014).

Conclusion

The method of reflux treatment did not influence the expression of miR-101 and miR-196a in Barrett's oesophagus. This data does not provide support to the hypothesis that surgical treatment of reflux better prevents cancer development in Barrett's oesophagus. The association between miR-196a expression and Barrett's oesophagus length is consistent with a tumour promoting role for miR-196a in Barrett's oesophagus.

Long-term follow-up after anti-reflux surgery in patients with Barrett's esophagus

BACKGROUND

Factors associated with the risk of progression of Barrett's esophagus remain unclear, and the impact of therapy on this risk remains uncertain. The aim of this study was to assess patients followed long-term after anti-reflux surgery for Barrett's esophagus.

METHODS

A retrospective review was performed of all patients with Barrett's who underwent anti-reflux surgery from 1989 to 2009 and had ≥5 years of follow-up.

RESULTS

There were 303 patients and 75 had follow-up ≥5 years. Median follow-up time for the 75 patients was 8.9 years (range 5-18). Regression was seen in 31%. Progression occurred in 8%, and these patients were significantly more likely to have a failed fundoplication (67% vs. 16%, p = 0.0129). The rate of progression from non-dysplastic Barrett's to high-grade dysplasia or cancer was 0.8% per patient year, and was seven times higher in patients with a failed fundoplication.

CONCLUSION

Compared to the accepted rate of progression of non-dysplastic Barrett's to high-grade dysplasia or cancer of 1.0% per patient year, anti-reflux surgery reduces this rate during long-term follow-up. The rate of progression was significantly lower in patients with an intact compared to a disrupted fundoplication, further suggesting that anti-reflux surgery can alter the natural history of Barrett's esophagus.