David F. Boerwinkel

The combination of autofluorescence endoscopy and molecular biomarkers is a novel diagnostic tool for dysplasia in Barrett's oesophagus

Objective Endoscopic surveillance for Barretts oesophagus (BO) is limited by sampling error and the subjectivity of diagnosing dysplasia. We aimed to compare a biomarker panel on minimal biopsies directed by autofluorescence imaging (AFI) with the standard surveillance protocol to derive an objective tool for dysplasia assessment. Design We performed a cross-sectional prospective study in three tertiary referral centres. Patients with BO underwent high-resolution endoscopy followed by AFI-targeted biopsies. 157 patients completed the biopsy protocol. Aneuploidy/tetraploidy; 9p and 17p loss of heterozygosity; RUNX3, HPP1 and p16 methylation; p53 and cyclin A immunohistochemistry were assessed. Bootstrap resampling was used to select the best diagnostic biomarker panel for high-grade dysplasia (HGD) and early cancer (EC). This panel was validated in an independent cohort of 46 patients. Results Aneuploidy, p53 immunohistochemistry and cyclin A had the strongest association with dysplasia in the per-biopsy analysis and, as a panel, had an area under the receiver operating characteristic curve of 0.97 (95% CI 0.95 to 0.99) for diagnosing HGD/EC. The diagnostic accuracy for HGD/EC of the three-biomarker panel from AFI+ areas was superior to AFI− areas (p<0.001). Compared with the standard protocol, this panel had equal sensitivity for HGD/EC, with a 4.5-fold reduction in the number of biopsies. In an independent cohort of patients, the panel had a sensitivity and specificity for HGD/EC of 100% and 85%, respectively. Conclusions A three-biomarker panel on a small number of AFI-targeted biopsies provides an accurate and objective diagnosis of dysplasia in BO. The clinical implications have to be studied further.

The Clinical Consequences of Advanced Imaging Techniques in Barrett's Esophagus

Evaluation of patients with Barretts esophagus (BE) using dye-based chromoendoscopy, optical chromoendoscopy, autofluorescence imaging, or confocal laser endomicroscopy does not significantly increase the number of patients with a diagnosis of early neoplasia compared with high-definition white light endoscopy (HD-WLE) with random biopsy analysis. These newer imaging techniques are not more effective in standard surveillance of patients with BE because the prevalence of early neoplasia is low and HD-WLE with random biopsy analysis detects most cases of neoplasia. The evaluation and treatment of patients with BE and early-stage neoplasia should be centralized in tertiary referral centers, where procedures are performed under optimal conditions, by expert endoscopists. Lesions that require resection are almost always detected by HD-WLE, although advanced imaging techniques can detect additional flat lesions. However, these are of limited clinical significance because they are effectively eradicated by ablation therapy. No endoscopic imaging technique can reliably assess submucosal or lymphangio-invasion. Endoscopic resection of early-stage neoplasia in patients with BE is important for staging and management. Optical chromoendoscopy can also be used to evaluate lesions before endoscopic resection and in follow-up after successful ablation therapy.

Detection of buried Barrett's glands after radiofrequency ablation with volumetric laser endomicroscopy.

BACKGROUND AND AIMS The prevalence and clinical relevance of buried Barretts glands (BB) after radiofrequency ablation (RFA) in Barretts esophagus (BE) are debated. Recent optical coherence tomography studies demonstrated a high prevalence of BBs. Direct histological correlation, however, has been lacking. Volumetric laser endomicroscopy (VLE) is a second-generation optical coherence tomography system capable of scanning a large surface of the esophageal wall layers with low-power microscopy resolution. The aim was to evaluate whether post-RFA subsquamous glandular structures (SGSs), detected with VLE, actually correspond to BBs by pursuing direct histological correlation with VLE images. METHODS In vivo VLE was performed to detect SGSs in patients with endoscopic regression of BE post-RFA. A second in vivo VLE scan was performed to confirm correct delineation of the SGSs. After endoscopic resection, the specimens were imaged ex vivo with VLE. Extensive histological sectioning of SGS areas was performed, and all histology slides were evaluated by an expert BE pathologist. RESULTS Seventeen patients underwent successful in vivo VLE (histological diagnosis before endoscopic treatment: early adenocarcinoma in 8 patients and high-grade dysplasia in 9). In 4 of 17 patients, no SGSs were identified during VLE, and a random resection was performed. In the remaining 13 patients (76%), VLE detected SGS areas, which were all confirmed on a second in vivo VLE scan and subsequently resected. Most SGSs identified by VLE corresponded to normal histological structures (eg, dilated glands and blood vessels). However, 1 area containing BBs was found on histology. No specific VLE features to distinguish between BBs and normal SGSs were identified. CONCLUSIONS VLE is able to detect subsquamous esophageal structures. One area showed BBs beneath endoscopically normal-appearing neosquamous epithelium; however, most post-RFA SGSs identified by VLE correspond to normal histological structures. ( CLINICAL TRIAL REGISTRATION NUMBER NTR4056.).

Effects of Autofluorescence Imaging on Detection and Treatment of Early Neoplasia in Patients With Barrett's Esophagus

BACKGROUND & AIMS Studies have reported that autofluorescence imaging (AFI) increases targeted detection of high-grade intraepithelial neoplasia (HGIN) and intramucosal cancer (IMC) in patients with Barretts esophagus (BE). We analyzed data from trials to assess the clinical relevance of AFI-detected lesions. METHODS We collected information on 371 patients with BE, along with endoscopy and histology findings, from databases of 5 prospective studies of AFI (mean age, 65 years; 305 male). We compared these data with outcomes of treatment and follow-up. Study end points included the diagnostic value of AFI (proportion of surveillance patients with HGIN or IMC detected only by AFI-targeted biopsies) and value of AFI in selection of therapy (the proportion of patients for which detection of an HGIN or IMC lesion by AFI changed the treatment strategy based on white-light endoscopy or random biopsy analysis). RESULTS Of study participants, 211 were referred for surveillance and 160 were referred for early stage neoplasia; HGIN or IMC were diagnosed in 147 patients. In 211 patients undergoing surveillance, 39 had HGIN or IMC (23 detected by white-light endoscopy, 11 detected by random biopsies, 5 detected by AFI). So, the diagnostic value of AFI was 5 (2%) of 211. In 24 patients, HGIN or IMC was diagnosed using only AFI. In 33 patients, AFI detected additional HGINs or IMCs next to lesions detected by primary white-light endoscopy. Lesions detected by AFI were treated in 57 patients: 26 patients underwent radiofrequency ablation and showed full remission of neoplasia, whereas 31 underwent endoscopic resection and 6 were found to have IMC. The value of AFI in selection of therapy was 6 (2%) of 371. CONCLUSIONS Based on an analysis of data from clinical trials of patients with BE, detection of lesions by AFI has little effect on the diagnosis of early stage neoplasia or therapeutic decision making. AFI therefore has a limited role in routine surveillance or management of patients with BE.

A randomized trial comparing multiband mucosectomy and cap-assisted endoscopic resection for endoscopic piecemeal resection of early squamous neoplasia of the esophagus.

BACKGROUND AND AIM Piecemeal endoscopic resection for esophageal high grade intraepithelial neoplasia (HGIN) or early squamous cell carcinoma (ESCC) is usually performed by cap-assisted endoscopic resection. This requires submucosal lifting and multiple snares. Multiband mucosectomy (MBM) uses a modified variceal band ligator without submucosal lifting. In high-risk areas where ESCC is common and endoscopic expertise is limited, MBM may be a better technique. We aimed to compare MBM to the cap-assisted technique for piecemeal endoscopic resection of esophageal ESCCs. METHODS Patients with mucosal HGIN/ESCC (2 - 6 cm, maximum two-thirds of esophageal circumference) were included. Lesions, delineated by 1.25 % Lugol staining, were randomized to MBM or cap-assisted piecemeal resection. Endpoints were procedure time and costs, complete endoscopic resection, adverse events, and absence of HGIN/ESCC at 3-month and 12-month follow-up.  RESULTS Endoscopic resection was performed in 84 patients (59 men, mean age 60) using MBM (n = 42) or the endoscopic resection cap (n = 42). There were no differences in baseline characteristics. Endoscopic complete resection was achieved in all lesions. Procedure time was significantly shorter with MBM (11 vs. 22 minutes, P < 0.0001). One perforation, seen after using the endoscopic resection cap, was treated conservatively. Total costs of disposables were lower for MBM (€200 vs. €251, P = 0.04). At 3-month and 12-month follow-ups none of the patients had HGIN/ESCC at the resection site. CONCLUSION Piecemeal endoscopic resection of esophageal ESCC with MBM is faster and cheaper than with the endoscopic resection cap. Both techniques are highly effective and safe. MBM may have significant advantages over the endoscopic resection cap technique, especially in countries where ESCC is extremely common but limited endoscopic expertise and resources exist. (Netherlands trial register: NTR 3246.).

Endoscopic TriModal imaging and biomarkers for neoplasia conjoined: a feasibility study in Barrett's esophagus.

In Barretts esophagus (BE), the normal squamous lining of the esophagus is replaced by specialized columnar epithelium. Endoscopic surveillance with autofluorescence imaging (AFI) and molecular biomarkers have been studied separately to detect early neoplasia (EN) in BE. The combination of advanced-imaging modalities and biomarkers has not been investigated; AFI may help detecting biomarkers as a risk-stratification tool. We retrospectively evaluated a cohort of patients undergoing endoscopy for EN in BE with AFI and correlated five biomarkers (HPP1, RUNX3, p16, cyclin A, and p53) in tissue samples with AFI and dysplasia status. Fifty-eight samples from a previous prospective study were selected: 15 true-positive (TP: AFI-positive, EN), 21 false-positive (FP: AFI-positive, no EN), 12 true-negative (TN1; AFI-negative, no EN in sample), 10 true-negative (TN2: AFI-negative, no EN in esophagus). Methylation-specific RT-PCR was performed for HPP1, RUNX3, p16, and immunohistochemistry for cyclin A, p53. P < 0.05 was considered statistically significant. Bonferroni correction was used for multiple comparisons. P16, cyclin A, p53 correlated with dysplasia (P < 0.01, P = 0.003, P < 0.001, respectively). Increased p16 methylation was observed between TP versus TN2 (P = 0.003) and TN1 versus TN2 (P = 0.04) subgroups, suggesting a field defect. Only p53 correlated with AFI-status (P = 0.003). After exclusion of EN samples, significance was lost. Although correlation with dysplasia status was confirmed for p16, cyclin A and p53, underlining the importance of these biomarkers as an early event in neoplastic progression, none of the investigated biomarkers correlated with AFI status. A larger prospective study is needed to assess the combination of AFI and a larger panel of biomarkers to improve risk stratification in BE.

Optimized endoscopic autofluorescence spectroscopy for the identification of premalignant lesions in Barrett's oesophagus.

Objective Fluorescence spectroscopy has the potential to detect early cellular changes in Barrett’s oesophagus before these become visible. As the technique is based on varying concentrations of intrinsic fluorophores, each with its own optimal excitation wavelength, it is important to assess the optimal excitation wavelength(s) for identification of premalignant lesions in patients with Barrett’s oesophagus. Methods The endoscopic spectroscopy system used contained five (ultra)violet light sources (&lgr;exc=369–416 nm) to generate autofluorescence during routine endoscopic surveillance. Autofluorescence spectroscopy was followed by a biopsy for histological assessment and spectra correlation. Three intensity ratios (r1, r2, r3) were calculated by dividing the area, A, under the spectral curve of selected emission wavelength ranges for each spectrum generated by each excitation wavelength &lgr;exc as follows . Double intensity ratios were calculated using two excitation wavelengths. Results Fifty-eight tissue areas from 22 patients were used for autofluorescence spectra analysis. Excitation with 395, 405 or 410 nm showed a significant (P⩽0.0006) differentiation between intestinal metaplasia and grouped high-grade dysplasia/early carcinoma for intensity ratios r2 and r3. A sensitivity of 80.0% and specificity of 89.5% with an area under the ROC curve of 0.85 was achieved using 395 nm excitation and intensity ratio r3. Conclusion Double excitation showed no additional value over single excitation. The combination of 395 nm excitation and intensity ratio r3 showed optimal conditions to discriminate nondysplastic from early neoplasia in Barrett’s oesophagus.

Fluorescence spectroscopy incorporated in an Optical Biopsy System for the detection of early neoplasia in Barrett's esophagus

Endoscopic surveillance is recommended for patients with Barretts esophagus (BE) to detect high-grade intraepithelial neoplasia (HGIN) or early cancer (EC). Early neoplasia is difficult to detect with white light endoscopy and random biopsies are associated with sampling error. Fluorescence spectroscopy has been studied to distinguish non-dysplastic Barretts epithelium (NDBE) from early neoplasia. The Optical Biopsy System (OBS) uses an optical fiber integrated in a regular biopsy forceps. This allows real-time spectroscopy and ensures spot-on correlation between the spectral signature and corresponding physical biopsy. The OBS may provide an easy-to-use endoscopic tool during BE surveillance. We aimed to develop a tissue-differentiating algorithm and correlate the discriminating properties of the OBS with the constructed algorithm to the endoscopists assessment of the Barretts esophagus. In BE patients undergoing endoscopy, areas suspicious for neoplasia and endoscopically non-suspicious areas were investigated with the OBS, followed by a correlating physical biopsy with the optical biopsy forceps. Spectra were correlated to histology and an algorithm was constructed to discriminate between HGIN/EC and NDBE using smoothed linear dicriminant analysis. The constructed classifier was internally cross-validated and correlated to the endoscopists assessment of the BE segment. A total of 47 patients were included (39 males, age 66 years): 35 BE patients were referred with early neoplasia and 12 patients with NDBE. A total of 245 areas were investigated with following histology: 43 HGIN/EC, 66 low-grade intraepithelial neoplasia, 108 NDBE, 28 gastric or squamous mucosa. Areas with low-grade intraepithelial neoplasia and gastric/squamous mucosa were excluded. The area under the receiver operating characteristic curve of the constructed classifier was 0.78. Sensitivity and specificity for the discrimination between NDBE and HGIN/EC of OBS alone were 81% and 58% respectively. When OBS was combined with the endoscopists assesssment, sensitivity was 91% and specificity 50%. If this protocol would have guided the decision to obtain biopsies, half of the biopsies would have been avoided, yet 4/43 areas containing HGIN/EC (9%) would have been inadvertently classified as unsuspicious. In this study, the OBS was used to construct an algorithm to discriminate neoplastic from non-neoplastic BE. Moreover, the feasibility of OBS with the constructed algorithm as an adjunctive tool to the endoscopists assessment during endoscopic BE surveillance was demonstrated. These results should be validated in future studies. In addition, other probe-based spectroscopy techniques may be integrated in this optical biopsy forceps system.

Prospective feasibility study on the use of multiband mucosectomy for endoscopic resection of early squamous neoplasia in the esophagus.

BACKGROUND AND STUDY AIMS Endoscopic resection for esophageal squamous high-grade intraepithelial neoplasia (HGIN) or intramucosal cancer (esophageal squamous cell carcinoma [ESCC]) with the endoscopic resection cap technique is technically difficult, and requires submucosal lifting and multiple snares for piecemeal resections. Multiband mucosectomy (MBM) is an easy-to-use endoscopic resection technique and may be the modality of choice in China, where ESCC is extremely prevalent. The aim of the current study was to prospectively evaluate MBM for piecemeal endoscopic resection of squamous neoplasia of the esophagus. METHODS Patients with HGIN/ESCC and no signs of submucosal invasion or metastatic disease were included in the study. Lesions were delineated using electrocoagulation and resected using the MBM technique. Endpoints were procedure time, endoscopic radicality, complications, histology of the endoscopic resection specimens, and absence of HGIN/ESCC at the endoscopic resection scar during follow-up. RESULTS A total of 41 patients (26 male; mean age 61 years) underwent MBM; all lesions were visible with white light endoscopy (median length 5 cm, interquartile range [IQR] 4 - 6 cm; median circumferential extent 42 %, IQR 25 - 50 %). Median procedure time was 12 minutes (IQR 8 - 24 minutes). Median number of resections was 5 (IQR 3 - 6). Endoscopic complete resection was achieved in all lesions. There was one perforation, which was treated by application of clips. No other complications were observed. The worst histology was ESCC (n = 19), HGIN (n = 17), middle grade intraepithelial neoplasia (n = 4), and normal squamous epithelium (n = 1). Endoscopic follow-up at 3 months showed HGIN at the endoscopic resection scar in two patients, which was effectively treated endoscopically, and showed normal squamous epithelium in all patients at final follow-up (median 15 months, IQR 12 - 24 months). CONCLUSION This first prospective study on MBM for piecemeal endoscopic resection of early esophageal squamous neoplasia showed that MBM was effective for the complete removal of lesions with short procedure time, few complications, effective histological assessment of resected specimens, and durable treatment effect.

Fluorescence imaging for the detection of early neoplasia in Barrett's esophagus: old looks or new vision?

Early neoplasia arising from Barrett’s esophagus is often small, focally distributed and endoscopically poorly visible, and random four-quandrant biopsies may easily miss early lesions. Advanced imaging techniques, such as (auto)fluorescence-based modalities, aim to increase the detection rate of early lesions or the yield of random biopsies. Fluorescence-based light–tissue interaction has been designed successfully in point-probe differentiating spectroscopy systems or integrated into wide-field endoscopic systems such as autofluorescence imaging (AFI). In this review, we discuss the most recent advances in fluorescence spectroscopy and imaging for detecting early Barrett’s neoplasia. A spectroscopy probe, integrated into regular biopsy forceps, was shown to offer decent discriminatory capabilities, while ensuring spot-on correlation between the measured area and the corresponding histology. With this tool, surveillance endoscopy with random biopsies may become more efficient and sensitive. AFI was shown to increase the targeted detection of early neoplasia. However, random biopsies could compensate for this effect. The clinical impact of AFI on the diagnosis and the treatment of early neoplasia is limited, and yet AFI may offer a novel approach in biomarker-based risk-stratification models. Moreover, in combination with new, readily available contrast agents such as fluorescent lectins, fluorescence imaging may receive renewed interest.