Willem A. Marsman

Endoscopic trimodal imaging detects colonic neoplasia as well as standard video endoscopy.

BACKGROUND & AIMS Endoscopic trimodal imaging (ETMI) is a novel endoscopic technique that combines high-resolution endoscopy (HRE), autofluorescence imaging (AFI), and narrow-band imaging (NBI) that has only been studied in academic settings. We performed a randomized, controlled trial in a nonacademic setting to compare ETMI with standard video endoscopy (SVE) in the detection and differentiation of colorectal lesions. METHODS The study included 234 patients scheduled to receive colonoscopy who were randomly assigned to undergo a colonoscopy in tandem with either ETMI or SVE. In the ETMI group (n=118), first examination was performed using HRE, followed by AFI. In the other group, both examinations were performed using SVE (n=116). In the ETMI group, detected lesions were differentiated using AFI and NBI. RESULTS In the ETMI group, 87 adenomas were detected in the first examination (with HRE), and then 34 adenomas were detected during second inspection (with AFI). In the SVE group, 79 adenomas were detected during the first inspection, and then 33 adenomas were detected during the second inspection. Adenoma detection rates did not differ significantly between the 2 groups (ETMI: 1.03 vs SVE: 0.97, P=.360). The adenoma miss-rate was 29% for HRE and 28% for SVE. The sensitivity, specificity, and accuracy of NBI in differentiating adenomas from nonadenomatous lesions were 87%, 63%, and 75%, respectively; corresponding values for AFI were 90%, 37%, and 62%, respectively. CONCLUSIONS In a nonacademic setting, ETMI did not improve the detection rate for adenomas compared with SVE. NBI and AFI each differentiated colonic lesions with high levels of sensitivity but low levels of specificity.

Combining Autofluorescence Imaging and Narrow-Band Imaging for the Differentiation of Adenomas from Non-Neoplastic Colonic Polyps Among Experienced and Non-Experienced Endoscopists

OBJECTIVES:Endoscopic tri-modal imaging incorporates high-resolution white-light endoscopy (HR-WLE), narrow-band imaging (NBI), and autofluorescence imaging (AFI). Combining these advanced techniques may improve endoscopic differentiation between adenomas and non-neoplastic polyps. In this study, we aimed to assess the interobserver variability and accuracy of HR-WLE, NBI, and AFI for polyp differentiation and to evaluate the combined use of AFI and NBI.METHODS:First, still images of 50 polyps (22 adenomas; median 3 mm) were randomly displayed to three experienced and four non-experienced endoscopists. All HR-WLE and NBI images were scored for Kudo classification and AFI images for color. Second, the combined AFI and NBI images were assessed using a newly developed algorithm by six additional non-experienced endoscopists.RESULTS:The outcomes measured were interobserver agreement and diagnostic accuracy using histopathology as reference standard. Experienced endoscopists had better interobserver agreement for NBI (κ=0.77) than for AFI (κ=0.33), whereas non-experienced endoscopists had better agreement for AFI (κ=0.58) than for NBI (κ=0.33). The accuracies of HR-WLE, NBI, and AFI among experienced endoscopists were 65, 70, and 74, respectively. Figures among non-experienced endoscopists were 57, 63, and 77. The algorithm was associated with a significantly higher accuracy of 85% among all observers (P<0.023). These figures were confirmed in the second evaluation study.CONCLUSIONS:Non-experienced endoscopists have better interobserver agreement and accuracy for AFI than for HR-WLE or NBI, indicating that AFI is easier to use for polyp differentiation in non-experienced setting. The newly developed algorithm, combining information of AFI and NBI together, had the highest accuracy and obtained equal results between experienced and non-experienced endoscopists.

Accuracy for Optical Diagnosis of Small Colorectal Polyps in Nonacademic Settings

BACKGROUND & AIMS When small colorectal lesions are accurately characterized, adenomas can be removed and discarded without formal histopathology analysis. Previous studies in an academic setting showed that many lesions can be managed accurately on the basis of their endoscopic image (optical diagnosis). We performed a prospective study to assess the accuracy of optical diagnosis of small colorectal polyps in a nonacademic setting (the DISCOUNT trial) by using high-resolution endoscopy (HRE) and narrow-band imaging (NBI). METHODS During colonoscopy, 1 of 3 nonacademic endoscopists characterized small lesions and declared whether this was done with low or high confidence. In cases of high confidence, the endoscopists decided whether lesions should be removed and discarded or whether they could be left in situ. A surveillance interval was then recommended on-site. RESULTS Of 215 patients in the study, 108 were found to have 281 small lesions. Of these lesions, 231 were characterized with high confidence by using HRE or NBI; the level of corresponding sensitivity was 77.0% (95% confidence interval, 68.4-83.8), and specificity was 78.8% (95% confidence interval, 70.6-85.2). Of these lesions, 164 were assigned for removal, and 67 were assigned to remain in situ, including 9 adenomas. In 54 patients, a surveillance interval could be recommended on-site that was in line with Dutch guidelines for 44 patients. CONCLUSIONS Even though many lesions were characterized by HRE or NBI with high confidence, optical diagnosis in a nonacademic setting proved to be disappointing, with a sensitivity of 77.0% and a specificity of 78.8%. Many lesions were accurately assigned to be removed or remain in situ, although few adenomas were assigned to remain in situ. Also, 19% of on-site recommendations for a surveillance interval proved to be inaccurate.

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 Barretts 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.

Potential impact of EUS-FNA staging of proximal lymph nodes in patients with distal esophageal carcinoma.

BACKGROUND AND STUDY AIMS Distal esophageal carcinomas can be resected using transthoracic esophagectomy or transhiatal esophagectomy. Accurate diagnosis of subcarinal and supracarinal lymph-node metastases is important for selecting the surgical strategy. The impact of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) on the preoperative diagnosis of subcarinal and supracarinal lymph-node metastases in patients with distal esophageal carcinoma was therefore investigated. PATIENTS AND METHODS Patients with a resectable distal esophageal carcinoma and subcarinal and/or supracarinal lymph nodes visualized on preoperative EUS were prospectively included. The lymph nodes were sampled using EUS-FNA, and if they were found to have metastases, transthoracic resection was offered; by contrast, patients without metastases were offered a transhiatal resection. RESULTS Lymph-node metastases were found with EUS-FNA in 11 of the 48 patients included (23 %). Thirteen patients had suspicious nodes on EUS, in four of whom (31 %) the diagnosis was changed into nonmalignant nodes with FNA. Thirty-five patients had nonsuspicious nodes on EUS, in three of whom (9 %) the FNA procedure revealed malignant cells. CONCLUSIONS EUS with the addition of the FNA procedure has a significant impact on decision-making in patients with esophageal carcinoma in whom transhiatal esophagectomy would otherwise be planned.

A genetically retargeted adenoviral vector enhances viral transduction in esophageal carcinoma cell lines and primary cultured esophageal resection specimens.

Objective: To evaluate if an integrin-retargeted adenoviral vector could establish a more efficient and tumor-specific gene transfer in esophageal carcinoma cells. Summary Background Data: Although preclinical data indicated that adenoviral gene therapy could be a promising novel treatment modality for various malignancies, clinical results are often disappointing. An important problem is the decreased tumoral expression of the Coxsackie and adenovirus receptor (CAR), which mediates adenoviral entry. Retargeting the adenoviral vector to other cellular receptors, by inserting an arginine-glycine-aspartate (RGD) tripeptide in the fiber knob, might overcome this problem. Methods: Four esophageal carcinoma cell lines and 10 fresh surgical resection specimens were cultured. All were infected with the native adenovirus (Ad) and the retargeted adenovirus (AdRGD), encoding for the reporter genes luciferase or Green Fluorescent Protein to analyze gene transfer efficiency. Results: In all cell lines, an increase in viral expression per cell and an increase in the percentage of transduced cells were seen with the retargeted adenovirus. Also, in the primary cultures of carcinoma cells, a more efficient gene transfer was seen when the retargeted vector was used. This phenomenon was less pronounced in normal cells, indicating that the RGD virus transduces tumor cells more efficiently than normal cells. Conclusions: This study demonstrates that an RGD retargeted adenovirus infects human esophageal carcinoma cells with enhanced efficiency, while in normal esophageal cells this effect is less pronounced. Therefore, this retargeted vector is expected to have a better performance in vivo, when compared with nonretargeted vectors used for cancer gene therapy so far.

Gene therapy for esophageal carcinoma: the use of an explant model to test adenoviral vectors ex vivo

Adenoviral gene therapy might be a promising therapeutic strategy for esophageal carcinoma. However, adenoviral transduction efficacy in vivo is still limited. This efficacy can be improved by the insertion of an Arg-Gly-Asp (RGD) peptide in the HI-loop of the viral fiber knob. Indeed in established esophageal cell lines, we observed an up to six-fold improved transduction using the RGD-targeted adenovirus. Established cell lines, however, are easily transformed and do not represent the more complex in vivo histology and anatomy. Therefore, we set up an esophageal explant model using esophageal biopsies from patients. Viability is a limiting factor for this system. Cultured squamous epithelium, intestinal metaplasia and squamous cell carcinoma had a sufficient viability to study adenoviral transduction. Viability of the cultured adenocarcinoma biopsies was poor. Adenoviral transduction in the explant model was poor and was localized in particular cells. The transduction of the nontargeted and RGD-targeted adenovirus was similar in localization and efficacy. In conclusion, we established an esophageal explant system to test the transduction of adenoviral vectors ex vivo. The transduction was limited and localized in specific cells. RGD-targeted adenovirus did not show an improved transduction in this system.

The Current State of Cancer Gene Therapy and Its Application in Esophageal Carcinoma

Advances in molecular genetics have accelerated the understanding of the genetic basis of many diseases. This is particularly true for esophageal adenocarcinoma with its well-defined premalignant lesions. At the same time, remarkable progress in recombinant DNA technology has enabled the development of molecular treatments for inherited disorders, infectious diseases and cancer. In recent years, especially the development of gene therapy systems as new treatment or prevention strategies for various malignant diseases has been explored. The present article deals with the general principles of gene therapy and then focuses on how these principles can be applied to esophageal cancer. Subsequently, the scarcely available experimental data from the literature are briefly reviewed. Finally, we summarize our experimental work over the last few years. Our main goal has been to develop an efficient and selective gene delivery system in order to maximize the proportion of successfully transduced tumor cells while sparing normal cells. Conclusion: The field of cancer gene therapy has evolved tremendously, with promising developments especially in the field of targeting and novel therapeutic genes. However, substantial research is still needed before gene therapy can play a significant role in the management of esophageal cancer. The focus of this research should be on further developing adequate experimental models as well as on improving gene-delivering vectors. Although it is unlikely that cancer gene therapy will replace the conventional methods of treatment, selective and efficient vectors may be used for patients with Barrett’s esophagus or as adjuvant therapy for patients with esophageal cancer in the future.

Gene therapy for barrett's esophagus: adenoviral gene transfer in different intestinal models

Adenoviral gene therapy could potentially be used for treatment of patients with a Barretts esophagus. In order to study the feasibility of this approach it is important to study adenoviral intestinal transduction both in vitro and in vivo. In the present study, we used differentiating Caco-2 cells, closed intestinal loops and a Barretts esophagus rat model to test transduction of adenoviruses expressing green fluorescent protein. We observed a decreased adenoviral transduction from 18.6 to 2.3% in undifferentiated and differentiated Caco-2 cells, respectively. This could be improved by the use of the mucolytic agent N-acetylcysteine (NAC) and the polycation diethylaminoethyl-dextran (DEAE-dextran), which improved transduction in differentiated cells five- and ten-fold, respectively. Also an RGD-retargeted adenovirus showed an improved transduction in differentiated cells. In closed intestinal loops adenoviral transduction was limited and the use of NAC and DEAE-dextran or RGD targeting had little effect. The Barretts esophagus rat model consisted of an esophagojejunostomy, which results in a Barretts esophagus and esophageal tumors within 6 months. Adenoviral transduction in this model was limited and mainly localized in the basal layer of normal esophagus and stromal tissue of a Barretts segment. We conclude that although the adenovirus shows promising results in vitro, the current adenoviral vectors are probably not suitable for patients with Barretts esophagus.

Epithelial cells in bone marrow: do they matter?

We read with great interest the letter of Steinert and colleagues ( Gut 2005; 54 :1045–6). They described disseminated epithelial cells in the bone marrow of patients with colorectal adenomas. As adenomas are non-cancerous, it is questionable whether these epithelial-like cells really represent disseminated cancer cells. If so, the benign nature of intraepithelial neoplasia is basically challenged. The search for micrometastatic disease in the bone marrow of cancer patients is an intriguing field in which many different diagnostic molecular modalities are being explored. However, the clinical impact of bone marrow micrometastatic disease is not clear. Patients with breast cancer frequently develop clinically manifest bone marrow metastases and in these patients …