Residual disease after neoadjuvant chemoradiotherapy for oesophageal cancer: locations undetected by endoscopic biopsies in the preSANO trial.

BACKGROUND: Active surveillance has been proposed for patients with oesophageal cancer in whom there is a complete clinical response after neoadjuvant chemoradiotherapy (nCRT). However, endoscopic biopsies have limited negative predictive value in detecting residual disease. This study determined the location of residual tumour following surgery to improve surveillance and endoscopic strategies. METHODS: The present study was based on patients who participated in the prospective preSANO trial with adenocarcinoma or squamous cell carcinoma of the oesophagus or oesophagogastric junction treated in four Dutch hospitals between 2013 and 2016. Resection specimens and endoscopic biopsies taken during clinical response evaluations after nCRT were reviewed by two expert gastrointestinal pathologists. The exact location of residual disease in the oesophageal wall was determined in resection specimens. Endoscopic biopsies were assessed for the presence of structures representing the submucosal layer of the oesophageal wall. RESULTS: In total, 119 eligible patients underwent clinical response evaluations after nCRT followed by standard surgery. Residual tumour was present in endoscopic biopsies from 70 patients, confirmed on histological analysis of the resected organ. Residual tumour was present in the resection specimen from 27 of the other 49 patients, despite endoscopic biopsies being negative. Of these 27 patients, residual tumour was located in the mucosa in 18, and in the submucosa beneath tumour-free mucosa in eight. One patient had tumour in muscle beneath tumour-free mucosa and submucosa. CONCLUSION: Most residual disease after nCRT missed by endoscopic biopsies was located in the mucosa. Active surveillance could be improved by more sampling and considering submucosal biopsies.

ANTECEDENTES: Se ha propuesto un seguimiento activo para los pacientes con cáncer de esófago en los que se logra una respuesta clínica completa tras quimiorradioterapia neoadyuvante (neoadjuvant chemoradiotherapy, nCRT). Sin embargo, las biopsias endoscópicas tienen un valor predictivo limitado para detectar la enfermedad residual. En este estudio se evaluó la localización del tumor residual tras la cirugía para poder determinar estrategias de seguimiento y endoscópicas. MÉTODOS: Este estudio se basa en pacientes que participaron en el ensayo prospectivo preSANO (adenocarcinoma o carcinoma escamoso del esófago o unión esofagogástrica en cuatro hospitales de los Países Bajos entre 2013 y 2016). Los especímenes quirúrgicos, así como las biopsias endoscópicas efectuadas durante las evaluaciones de la respuesta clínica después de nCRT fueron revisadas por dos patólogos gastrointestinales expertos. En los especímenes de resección, se determinó la localización exacta de la enfermedad residual en la pared del esófago. Se evaluaron las biopsias endoscópicas para identificar estructuras que constituyeran la capa submucosa de la pared del esófago. RESULTADOS: En total, 119 pacientes elegibles fueron sometidos a evaluaciones de la respuesta clínica tras nCRT seguida de cirugía estándar. Se detectó tumor residual en las biopsias endoscópicas de 70 pacientes, luego confirmadas en la histología de la pieza extirpada. Se identificó tumor residual en la pieza de resección de 27 de los otros 49 pacientes, a pesar de que las biopsias endoscópicas fueron negativas. En estos 27 pacientes, 18 presentaban tumor residual en la mucosa y ocho pacientes en la submucosa mas allá de una mucosa libre de tumor. Un paciente tenía tumor en el músculo más allá de una mucosa y submucosa libres de tumor. CONCLUSIÓN: La mayoría de los casos de enfermedad residual tras nCRT que no se detectaron en las biopsias endoscópicas, se localizaban en la mucosa. El seguimiento activo podría mejorar con la toma de más muestras y considerando las biopsias submucosas.

The Y-chromosome F haplogroup contributes to the development of Barrett's esophagus-associated esophageal adenocarcinoma in a white male population.

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus, resulting from longstanding gastroesophageal reflux disease (GERD). BE predisposes for the highly malignant esophageal adenocarcinoma (EAC). Both BE and EAC have the highest frequencies in white males. Only a subset of patients with GERD develop BE, while <0.5% of BE will progress to EAC. Therefore, it is most likely that the development of BE and EAC is associated with underlying genetic factors. We hypothesized that in white males, Y-chromosomal haplogroups are associated with BE and EAC. To investigate this we conducted a multicenter study studying the frequencies of the Y-chromosomal haplogroups in GERD, BE, and EAC patients. We used genomic analysis by polymerase chain reaction and restriction fragment length polymorphism to determine the frequency of six Y-chromosomal haplogroups (DE, F(xJ,xK), K(xP), J, P(xR1a), and R1a) between GERD, BE, and EAC in a cohort of 1,365 white males, including 612 GERD, 753 BE patients, while 178 of the BE patients also had BE-associated EAC. Univariate logistic regression analysis was used to compare the outcomes. In this study, we found the R1a (6% vs. 9%, P = 0.04) and K (3% vs. 6%, P = 0.035) to be significantly underrepresented in BE patients as compared to GERD patients with an odds ratio (OR) of 0.63 (95% CI 0.42-0.95, P = 0.03) and of 0.56 (95% CI 0.33-0.96, P = 0.03), respectively, while the K haplogroup was protective against EAC (OR 0.30; 95% CI 0.07-0.86, P = 0.05). A significant overrepresentation of the F haplogroup was found in EAC compared to BE and GERD patients (34% vs. 27% and 23%, respectively). The F haplogroup was found to be a risk factor for EAC with an OR of 1.5 (95% CI 1.03-2.19, P = 0.03). We identified the R1a and K haplogroups as protective factors against development of BE. These haplogroups have low frequencies in white male populations. Of importance is that we could link the presence of the predominantly occurring F haplogroup in white males to EAC. It is possible that this F haplogroup is associated to genetic variants that predispose for the EAC development. In future, the haplogroups could be applied to improve stratification of BE and GERD patients with increased risk to develop BE and/or EAC.

The Amsterdam ReBus progressor cohort: identification of 165 Barrett's surveillance patients who progressed to early neoplasia and 723 nonprogressor patients.

Patient selection is suboptimal in most studies focused on identifying biological markers for neoplastic progression in Barrett's esophagus (BE). This study aims to describe a stringently selected community-based case-control cohort of non-dysplastic BE (NDBE) patients who progressed to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) and BE patients who never progressed to be used for future biomarker studies. We identified all patients referred for endoscopic work-up of BE neoplasia at three tertiary referral centers for treatment of BE neoplasia between 2000 and 2013. We performed a detailed registration of any endoscopic surveillance history before neoplastic progression. Controls were selected from a retrospective BE surveillance registration in 10 community hospitals. A total of 887 patients were referred for endoscopic work-up of BE neoplasia. Based on predefined selection criteria, we identified 165 progressor patients (82% men; mean age 55 years ± 10.4) with a baseline endoscopy demonstrating NDBE > 2 years before neoplastic progression. Using the same predefined selection criteria, 723 nonprogressor patients (67% men; mean age 57 years ± 11.3) with >2 years of endoscopic surveillance were identified. Median length of the BE segment was 5 cm (IQR 4-7) in progressors and 4 cm (IQR 2-6) in controls. Median duration of surveillance was 89 months (IQR 54-139) in progressors and 76 months (IQR 47-116) in nonprogressors. Paraffin embedded biopsies are available for biomarker research in all patients. Ethical approval was obtained and material transfer agreements were signed with all 58 contributing pathology labs. This is the largest community-based case-control cohort of BE patients with and without progression to early neoplasia. The stringent selection criteria and the availability of paraffin embedded biopsy specimens make this a unique cohort for biomarker studies.

Predictive biomarkers for Barrett's esophagus: so near and yet so far.

Barrett's esophagus (BE) is the strongest risk factor for the development of esophageal adenocarcinoma. However, the risk of cancer progression is difficult to ascertain in individuals, as a significant number of patients with BE do not necessarily progress to esophageal adenocarcinoma. There are several issues with the current strategy of using dysplasia as a marker of disease progression. It is subject to sampling error during biopsy acquisition and interobserver variability among gastrointestinal pathologists. Ideal biomarkers with high sensitivity and specificity are needed to accurately detect high-risk BE patients for early intervention and appropriate cost-effective surveillance. To date, there are no available molecular tests in routine clinical practice despite known genetic and epigenetic aberrations in the Barrett's epithelium. In this review, we present potential biomarkers for the prediction of malignant progression in BE. These include markers of genomic instability, tumor suppressor loci abnormalities, epigenetic changes, proliferation markers, cell cycle predictors, and immunohistochemical markers. Further work in translating biomarkers for routine clinical use may eventually lead to accurate risk stratification.

A genomic biomarker-based model for cancer risk stratification of non-dysplastic Barrett's esophagus patients after extended follow up; results from Dutch surveillance cohorts.

Barrett's esophagus is the only known mucosal precursor for the highly malignant esophageal adenocarcinoma. Malignant degeneration of non-dysplastic Barrett's esophagus occurs in < 0.6% per year in Dutch surveillance cohorts. Therefore, it has been proposed to increase the surveillance intervals from 3 to 5 years, potentially increasing development of advanced stage interval cancers. To prevent such cases robust biomarkers for more optimal stratification over longer follow up periods for non-dysplastic Barrett's patients are required. In this multi-center study, aberrations for chromosomes 7, 17, and structural abnormalities for c-MYC, CDKN2A, TP53, Her-2/neu and 20q assessed by DNA fluorescence in situ hybridization on brush cytology specimens, were used to determine marker scores and to perform clonal diversity measurements, as described previously. In this study, these genetic biomarkers were combined with clinical variables and analyzed to obtain the most efficient cancer prediction model after an extended period of follow-up (median time of 7 years) by applying Cox regression modeling, bootstrapping and leave-one-out analyses. A total of 334 patients with Barrett's esophagus without dysplasia from 6 community hospitals (n = 220) and one academic center (n = 114) were included. The annual progression rate to high grade dysplasia and/or esophageal adenocarcinoma was 1.3%, and to adenocarcinoma alone 0.85%. A prediction model including age, Barrett circumferential length, and a clonicity score over the genomic set including chromosomes 7, 17, 20q and c-MYC, resulted in an area under the curve of 0.88. The sensitivity and specificity of this model were 0.91 and 0.38. The positive and negative predictive values were 0.13 (95% CI 0.09 to 0.19) and 0.97 (95% CI 0.93 to 0.99). We propose the implementation of the model to identify non-dysplastic Barrett's patients, who are required to remain in surveillance programs with 3-yearly surveillance intervals from those that can benefit from less frequent or no surveillance.

Expression pattern of immune suppressive cytokines and growth factors in oesophageal adenocarcinoma reveal a tumour immune escape-promoting microenvironment.

Immunotherapy for solid cancers, such as oesophageal adenocarcinoma (OAC), is generally hampered by an unfavourable immunological tumour microenvironment. This prompted us to investigate the nature of the OAC environment. Biopsies of tumour and normal control tissues were collected from 17 OAC patients, and investigated using fluorescent immunohistochemistry (IHC) for the expression of cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), transforming growth factor-beta, indoleamine 2-3 dioxygenase, CXCL3 and CXCR1, and for measuring a panel of cytokines by cytometric bead array (CBA), and for Granzyme B (GrB), Perforin and PI9 detection by semi-quantitative PCR (QPCR). IHC showed that expression of all the above-mentioned factors is upregulated in 80-93% of the tumours. By QPCR, the cytokine interleukin (IL)-8 was significantly upregulated in tumour samples (P < 0.05). IL-6, IL-10, GrB and Perforin did not show any significant difference between normal and tumour samples, whereas PI9 levels were significantly higher in normal when compared with the tumour samples. CBA confirmed upregulation of IL-8 and show upregulation of IL-1beta in the tumours (P < 0.05). Regarding IL-6 and interferon (IFN)-gamma, no significant differences were observed between normal and tumour tissues. The OAC microenvironment is characterized by a lack of cytokines and factors that normally would enhance anti-cancer responses, such as IFN-gamma and GrB, and by a high expression of several immuno-suppressive factors, such as COX-2, VEGF and IL-8. For future improvement of treatment efficacy of OAC patients, it will be of importance to combine immunotherapy with immune-modulating agents.

Stepwise circumferential and focal ablation of Barrett's esophagus with high-grade dysplasia: results of the first prospective series of 11 patients.

BACKGROUND AND STUDY AIMS: Stepwise circumferential and focal ablation of nondysplastic Barrett's esophagus has proven safe and effective. This study assessed the efficacy and safety of ablation for Barrett's esophagus with high-grade dysplasia (HGD), and residual Barrett's esophagus with dysplasia after prior endoscopic resection for visible lesions. PATIENTS AND METHODS: This was a prospective cohort study. All visible abnormalities were resected prior to ablation. Persistence of dysplasia and absence of invasive cancer was confirmed with biopsies after endoscopic resection. A balloon-based electrode was used for primary circumferential ablation and an endoscope-mounted electrode was used for secondary focal ablation. Eradication of dysplasia and Barrett's esophagus was the main outcome measure. RESULTS: Eleven patients (eight men; median age 60 years) were treated (median Barrett's length 5 cm). Visible abnormalities were removed with endoscopic resection in six patients. The worst pathological grade of residual Barrett's esophagus after endoscopic resection and prior to ablation was LGD (n = 2) and HGD (n = 9). Patients underwent a median of two circumferential and two focal ablation sessions. Complete remission of dysplasia and complete endoscopic and histological removal of Barrett's esophagus was achieved in 11/11 patients (100%). There were no adverse events or strictures, and in none of the 473 biopsies of neo-squamous mucosa was subsquamous Barrett's esophagus ("buried Barrett's") observed. During a median follow-up period of 14 months after the last treatment session and a median number of two follow-up endoscopies, none of the patients showed recurrence of dysplasia or endoscopic signs of recurrent Barrett's mucosa. CONCLUSIONS: Stepwise circumferential and focal ablation appears to be a safe and effective treatment for complete removal of Barrett's esophagus containing HGD, and can be safely performed after prior endoscopic resection for endoscopically visible abnormalities.

High throughput techniques for characterizing the expression profile of Barrett's esophagus.

Barrett's esophagus (BE) is the metaplastic change of the normal lined squamous epithelium of the distal esophagus to a columnar type of epithelium as a result of chronic long-standing gastroesophageal reflux disease. Patients with BE have a significantly increased risk of developing an esophageal adenocarcinoma, with an estimated annual incidence varying from 0.4 to 1.8%. Over the last 3 decades, the incidence of BE and its associated adenocarcinoma has increased in Western countries at a rate that exceeds that of any other malignancy. Despite all the research performed on BE, there is still an inadequate understanding of the biological basis of this mucosal transformation. With the upcoming modern high throughput technologies, important progression has been made in unraveling the expression profiles and gaining more insight in the biology of BE and esophageal adenocarcinoma. Several studies reported genome, transcriptome, proteome, and kinome investigations using high throughput techniques. These studies were conducted to find biomarkers that can be used to detect BE patients with increased risk for malignant progression or to obtain more insight in the mechanism underlying BE development. In the following review, we first discuss the different techniques that are currently available and summarize findings in this field, including several recent publications of our group.

The effect of oral administration of ursodeoxycholic acid and high-dose proton pump inhibitors on the histology of Barrett's esophagus.

Bile acids may play a role in the pathogenesis of Barrett's esophagus (BE). Bile composition can be influenced by oral administration of ursodeoxycholic acid (UDCA). We prospectively investigated the effect of proton pump inhibitors (PPI) supplemented with UDCA in vivo in patients with BE. Patients with no or low-grade dysplasia who were clinically asymptomatic on PPI were eligible for the study. In order to exclude the effects of acid reflux, all patients were initially treated with 40 mg esomeprazole (ESO) twice daily for 6 months and continued on this dose till the end of the study (t = 12 months). During a period of 6 months (t = 6 month - t = 12 month) patients were treated with oral UDCA (600 mg twice daily). Patients underwent endoscopy at t = 0 months, t = 6 months and t = 12 months with multiple biopsies of the distal and proximal BE segment, normal squamous and gastric cardia. In addition, pH was measured at t = 0 months and t = 6 months using a BRAVO wireless pH capsule. Bile was sampled at the beginning of the UDCA treatment and 6 months later (t = 6 month and t = 12 month). All biopsies were reviewed for the extent of metaplasia, dysplasia, and acute and chronic inflammation. In addition, proliferation (Ki67), differentiation (villin, cytokeratins 7 and 20) and inflammation (COX-2) were investigated by immunohistochemistry (IHC). Nine patients (mean age 60 years, median BE length 7 cm) were included, of whom six had no dysplasia and three had low-grade dysplasia. pH measurements revealed a normal acid exposure in most patients at t = 0 and t = 6 months. In addition, bile composition analysis demonstrated the efficacy of UDCA. Combining the results of both phases of the study, no significant changes were seen in any of the histological or IHC parameters. Differentiation and proliferation parameters showed no significant changes. In this study, in BE patients who were clinically asymptomatic on PPI, increasing the PPI dose to the maximum for 6 months followed by the addition of UDCA for 6 months did not result in significant histological or IHC changes in their BE.

Surveillance history of endoscopically treated patients with early Barrett's neoplasia: nonadherence to the Seattle biopsy protocol leads to sampling error.

SUMMARY: The study's aim was to retrospectively evaluate the surveillance history of Barrett's esophagus (BE) patients with endoscopically treated early neoplasia. All BE patients endoscopically treated for early cancer (EC) or high-grade intraepithelial neoplasia (HGIN) in a lesion or mass between 1998 and 2005 were included. Endoscopy and histology records were reviewed. Ninety-four patients (78 males, mean age 67 years, 24 HGIN, 70 EC) were included. In 36 (38%) patients, HGIN/EC was diagnosed at (or within 6 months after) initial endoscopy. The remaining 58 (62%) patients had a surveillance history (median duration 7 years, mean 6.7 endoscopies). Seventy-nine percent of these had low-grade intraepithelial neoplasia (LGIN) diagnosed at least once during their surveillance period with a median of seven endoscopies and a median number of biopsies that was 50% of what should have been taken according to the Seattle protocol. Patients without any dysplasia during earlier surveillance (n = 12, 21%) had undergone significantly less endoscopies (median four endoscopies, P = 0.02) and had a median biopsy percentage that was 23% of the Seattle protocol (P < 0.001 versus 50% in LGIN). In this selected cohort of patients with early Barrett's neoplasia, 38% of patients were diagnosed at initial endoscopy. Of the patients with a surveillance history, 79% had shown LGIN prior to HGIN/EC diagnosis. Only 21% of patients had a surveillance history without any dysplasia, which in general encompassed endoscopies with an insufficient number of biopsies, suggesting sampling error. This underlines the importance of obtaining an adequate number of biopsies during surveillance endoscopies.

Gene expression profile comparison of Barrett's esophagus epithelial cell cultures and biopsies.

Barrett's esophagus (BE) is a metaplastic process in which the normal squamous epithelium of the distal esophagus is replaced by columnar lined epithelium. The aim was to gain more insight in the process of metaplasia and to identify which genes are specifically expressed by the epithelial cells and the surrounding tissues in BE. Hereto, the gene expression profile of a BE epithelial primary cell culture was compared to that of a BE biopsy. To specifically obtain the epithelial cell layer, epithelial cells from biopsies of BE were cultured using a Barrett specific culturing medium. Serial analysis of gene expression was applied to obtain a transcription library of the primary epithelial cell culture. The transcriptome was analyzed and compared to a previously described transcriptome of a BE biopsy. Validation of results by reverse transcriptase-polymerase chain reaction was performed using tissues of 16 BE patients and 16 primary cell cultures. Over 43,000 tags were sequenced. Genes specifically expressed by the Barrett epithelial cells were for instance Lipocalin 2 and Cyclin D1, whereas annexin A10, trefoil factor (TFF)1 and TFF2 were specifically expressed in the BE biopsies. The comparison of the gene expression profiles of BE primary cultured epithelial cells with BE biopsy defines a subset of genes that are specifically expressed by the epithelial cells and another subset that most likely is expressed by the underlying stromal tissues in the BE biopsy specimens.

Esophageal sensitivity to acid in patients with Barrett's esophagus is not related to preserved esophageal mucosal integrity.

BACKGROUND: Patients with Barrett's esophagus (BE) usually have severe gastroesophageal reflux. However, they often have surprisingly few reflux symptoms. We hypothesized that BE patients are less sensitive to acid than gastroesophageal reflux disease (GERD) patients without Barrett and that this is due to an unusual preservation of mucosal integrity of the squamous epithelium prohibiting transepithelial acid diffusion. METHODS: We prospectively analyzed esophageal sensitivity and esophageal mucosal integrity in GERD patients with and without BE and healthy subjects. An acid perfusion test was performed and mucosal integrity was assessed in vivo by electrical tissue impedance spectroscopy and ex vivo by Ussing chamber experiments with biopsy specimens. KEY RESULTS: Gastroesophageal reflux disease patients with BE were less sensitive to acid than GERD patients without BE, but more sensitive to acid than healthy controls (time to perception Barrett's 14.0 minutes, GERD 4.6 minutes, controls 17.5 minutes). However, extracellular impedance (6.2 and 5.7 vs 8.4×103  Ω/m) and transepithelial resistance (94.0 and 89 vs 118 Ω/cm2 ) was similar in BE and GERD patients and significantly lower than in healthy subjects. Transepithelial fluorescein flux was equally increased in GERD patients with and without BE (1.6 and 1.7×103 vs 0.6×103  nmol/cm2 /h). CONCLUSIONS & INFERENCES: Esophageal hypersensitivity to acid is less pronounced in BE patients than in GERD patients without Barrett. However, mucosal integrity of the squamous epithelium is equally impaired in GERD patients with and without Barrett, indicating that factors other than esophageal mucosal barrier integrity explain the difference in acid sensitivity between those with BE and those without.

Accumulation of genetic abnormalities during neoplastic progression in Barrett's esophagus.

Sex chromosome status, ploidy, and proliferation rate were evaluated in archival material of 73 Barrett's esophagus patients (48 males and 25 females). Diagnosis in esophageal mucosa samples ranged from intestinal metaplasia with no dysplasia to invasive esophageal adenocarcinoma; also, four lymph node metastases were studied. Chromosomal and ploidy aberrations were determined by in situ hybridization with repetitive DNA probes specific for chromosomes Y, X, and 1. Proliferation index (Ki-67 protein expression) was assessed by immunohistochemistry. Proliferation rate was elevated in all stages of dysplasia and in the adenocarcinomas. Aneuploidy (hyperdiploidy) and loss of the Y chromosome correlated with the advancing stages toward neoplasia (P < 0.001) and reached high prevalences (70-100%) in high-grade dysplasia and adenocarcinoma. Abnormalities of the X chromosome were not seen. These data suggest that in Barrett's esophagus, genetic perturbations may be generated in relation to a high proliferation rate.

Detection of chromosomal changes by interphase cytogenetics in biopsies of recurrent astrocytomas and oligodendrogliomas.

Recently, lineage-specific genetic pathways of tumor progression have been suggested in both oligodendrogliomas and astrocytomas. Aberrations consistently reported in gliomas include chromosomes 1, 7, 10, 17 and 19. Identification of specific genetic damage may have important clinical consequences, because oligodendrogliomas, unlike astrocytomas, are responsive to chemotherapy. Genetic alterations specific for tumor type and tumor progression were investigated in 5 pairs of recurrent astrocytomas and 8 pairs of recurrent oligodendrogliomas by means of interphase in situ hybridization (ISH) to paraffin-embedded, formalin-fixed tissue sections. A set of DNA probes specific for the centromeric regions of chromosomes 1, 7, 10, 17, X and Y was applied. Since LOH studies on oligodendrogliomas have revealed losses in the region of 1p32-1p36, a DNA probe specific for the 1p36.3 locus was included. Hybridization with the 1p36.3 probe revealed loss of 1p in 5 of the 8 oligodendroglioma recurrences, the aberration being present in the primary tumors in 2 cases. In none of the astrocytomas was loss of 1p observed. Numerical aberrations were found in one astrocytoma pair (+7) and in the second biopsy of an oligodendroglioma (+7, -10). Aneuploidy was found by in situ hybridization in 8 of the 13 tumor pairs. Detection of aberrations in the 1p36.3 locus by interphase in situ hybridization to paraffin-embedded, formalin-fixed tumors may become a very useful tool in delineation of oligodendroglial from astrocytic genotypes, directing tumor specific therapy. The technique may be of crucial importance in tumor cases in which histologic criteria of lineage are not obvious.

Biomarkers in Barrett esophagus.

Barrett esophagus is a premalignant condition that may progress to adenocarcinoma. The risk of developing cancer has been estimated to be approximately 1 in 250 patient-years of observation; however, there appear to be subsets of patients at much higher risk. Risk stratification has previously been determined by histological identification of dysplasia. Several new biomarkers are being tested to help clinicians better determine the risk of cancer development. Although none of these biomarkers has been proven in a prospective study to predict the onset of cancer, they have been correlated with cancer development. Most of these are factors that have been associated with cancer development in other organs. These include assessment of cell proliferation, expression of cyclooxygenase 2, growth factors and oncogenes, secretory factors, cell cycle proteins, adhesion molecules, and aneuploidy and other genetic abnormalities. In addition to their role as potential cancer biomarkers, these factors have increasingly been reported as surrogate markers to monitor the effectiveness of conservative treatments for Barrett esophagus. In this article, biological markers are reviewed for their relevance in Barrett esophagus. Although most biological markers need to be evaluated further and, for most, prospective follow-up studies are lacking, at present abnormal ploidy status, P16 and P53 gene abnormalities, or allelic losses are the most extensively documented.

Prognostic value of p53 in Barrett's oesophagus.

During the last 30 years, the incidence of oesophageal adenocarcinoma has increased rapidly. Patients with Barrett's oesophagus have an increased risk of developing oesophageal adenocarcinoma and should be kept under surveillance. However, only a subset of Barrett's oesophagus patients will eventually develop malignancy and surveillance programs using endoscopy and histopathology cannot efficiently identify this subgroup. The study of additional prognostic factors is therefore of major importance and the p53 tumour suppressor gene has attracted much attention in this respect. Several investigators have found that p53 alteration is a frequent event in oesophageal adenocarcinomas and is associated with malignant transformation of Barrett's oesophagus. p53 appears to be a promising prognostic marker in Barrett's oesophagus and, as research progresses, possible clinical applications are emerging.

[Barrett's esophagus: new developments in endoscopic surveillance]. / Barrett-slokdarm: nieuwe ontwikkelingen in endoscopische surveillance.

The current surveillance strategies for patients with a Barrett's oesophagus are hampered by the poor endoscopic visibility of early neoplastic lesions, the sampling error of random biopsies, the subjectivity of the histological evaluation, and the low incidence of carcinoma. New endoscopic techniques are available for a more reliable evaluation of a Barrett's oesophagus: high-resolution endoscopy, chromoendoscopy, fluorescence endoscopy and optical coherence tomography. The use of molecular markers will probably lead to a better risk stratification of patients. Detection of aneuploid cell populations and assessment of an increase of the number of cells in the S- and G2-phase are possible with DNA flow cytometry; flow cytometric abnormalities may be a more reliable predictor of carcinoma than histological assessment. A combined approach with the new endoscopic techniques and molecular markers may lead to a more efficient and cost-effective surveillance programme.

[Barrett's esophagus: endoscopic treatment of high-grade dysplasia and early cancer]. / Barrett-slokdarm: endoscopische behandeling van hooggradige dysplasie en vroegcarcinomen.

In a Barrett's oesophagus without dysplasia, endoscopic control every 3-5 years is sufficient. If low-grade dysplasia is encountered in the surveillance biopsies, then endoscopy should be repeated within 3-6 months and yearly thereafter if the low-grade dysplasia persists. Antacid medication must be prescribed in cases with extensive inflammation. The endoscopic treatment of patients with high-grade dysplasia and/or early cancer of the mucosa in a Barrett's oesophagus (tissue ablation and/or mucosa resection) seems a promising alternative to surgery in view of the combination of effectiveness, limited invasiveness compared to surgical resection, and the preservation of a functional oesophagus. Data from long-term follow-up are still limited. Strict endoscopic surveillance will probably detect metachronic abnormalities in an early and still curable stage, creating a new opportunity for endoscopic treatment.