Radiofrequency ablation for Barrett's dysplasia: past, present and the future?

Outcomes of Radiofrequency Ablation Compared to Liquid Nitrogen Spray Cryotherapy for the Eradication of Dysplasia in Barrett's Esophagus

INTRODUCTION

Current guidelines recommend endoscopic eradication therapy (EET) for Barrett's esophagus (BE) with dysplasia and intramucosal adenocarcinoma using either radiofrequency ablation (RFA) or liquid nitrogen spray cryotherapy (LNSC). The aims of this multicenter study are to compare the rate and number of treatment sessions of RFA vs. LNSC to achieve CE-D and CE-IM and assess outcomes for those who switched therapy.

METHODS

This is a retrospective cohort study of patients with BE undergoing EET. Demographics, baseline variables, endoscopy details, and histology information were abstracted.

RESULTS

One hundred and sixty-two patients were included in this study with 100 patients in the RFA group and 62 patients in the LNSC group. The rate of CE-D and CE-IM did not differ between the RFA group and LNSC group (81% vs. 71.0%, p = 0.14) and (64% vs. 66%, p = 0.78), respectively. The number of sessions to achieve CE-D and CE-IM was higher with LNSC compared to RFA (4.2 vs. 3.2, p = 0.05) and (4.8 vs. 3.5, p = 0.04), respectively. The likelihood of developing recurrent dysplasia was higher among patients who did not achieve CE-IM (12%) compared to those who did achieve CE-IM (4%), p = 0.04. Similar findings were found in those who switched treatment modalities.

DISCUSSION

EET is highly effective in eradication of Barrett's associated dysplasia and neoplasia. Both RFA and LNSC achieved similar rates of CE-D and CE-IM although LNSC required more sessions. Also, achievement of CE-IM was associated with less recurrence rates of dysplasia.

Cryotherapy and Radiofrequency Ablation for Eradication of Barrett's Esophagus with Dysplasia or Intramucosal Cancer

BACKGROUND AND AIMS

Endoscopic ablation therapy has become the mainstay of treatment of Barrett's associated dysplasia and intramucosal cancer (IMC). The widely available techniques for ablation are radiofrequency ablation (RFA) and cryotherapy. Our aim was to compare eradication rates of metaplasia and dysplasia with both these modalities.

PATIENTS AND METHODS

Retrospective review of prospectively collected database of patients who underwent endoscopic therapy for Barrett's dysplasia or IMC from 2006 to 2011 was performed. Demographic features, comorbidities, and endoscopic data including length of Barrett's segment, hiatal hernia size, interventions during the endoscopy and histological results were reviewed.

RESULTS

Among 154 patients included, 73 patients were in the RFA and 81 patients were in the cryotherapy group. There was complete eradication of intestinal metaplasia (CE-IM) in 81 (52.6%), complete eradication of dysplasia (CE-D) in 133 (86.4%), and persistent dysplasia or cancer in 19 patients (12.3%). Compared to RFA, cryotherapy patients were found to be older and less likely to have undergone endoscopic mucosal resection. On multivariate analysis, patients who underwent RFA had a threefold higher odds of having CE-IM than those who underwent cryotherapy (odds ratio [OR] 2.9, 95% confidence interval [CI] 1.4-6.0, p = 0.004), but CE-D were similar between the two groups (OR 1.7, 95% CI 0.66-4.3, p = 0.28).

CONCLUSIONS

Endoscopic therapy is highly effective in eradication of Barrett's associated neoplasia. Patients who underwent cryotherapy were equally likely to achieve CE-D but not CE-IM than patients who underwent RFA. Patient characteristics and preferences may effect choice of treatment selection and outcomes.

Long-term outcomes of the randomized controlled trial comparing 5-aminolaevulinic acid and Photofrin photodynamic therapy for Barrett's oesophagus related neoplasia

OBJECTIVE

Photodynamic therapy (PDT) was used as therapy for early neoplasia associated with Barrett's oesophagus (BE). This is 5-year follow-up of patients enrolled into randomised controlled trial of 5-aminolaevulinic acid (ALA) vs. Photofrin PDT.

METHODS

Biopsies were taken from original Barrett's segment during endoscopic follow up using Seattle protocol. Endoscopic mucosal resection (EMR) ± radiofrequency ablation (RFA) was preferred therapy in patients who failed PDT and/or had recurrent neoplasia.

RESULTS

Fifty eight of 64 patients enrolled in the original trial were followed up including 31 patients treated with ALA PDT (17 patients with ≤6 cm, 14 patients with >6 cm segment of BE) and 27 treated with Photofrin PDT (14 patients with ≤6 cm, 13 patients with >6 cm BE). Initial success was achieved in 65% (20/31) ALA and 48% (13/27) Photofrin patients (p = .289). Thirty five percent patients (7/20) relapsed in ALA group and 54% (7/13) relapsed in Photofrin group (p = .472). At a median follow-up of 67 months, no significant difference was found in long-term complete reversal of intestinal metaplasia (CR-IM) and complete reversal of dysplasia (CR-D) between ALA and Photofrin groups (78% vs. 63%; p = .18; 90% vs. 76%; p = .26). Original length of BE did not alter long-term outcome. Four patients from each group progressed to invasive oesophageal adenocarcinoma. Initial success of ALA PDT was associated with significantly better likelihood of long-term remission (p = .03).

CONCLUSIONS

Initial response to PDT plays key role in long term outcome. RFA ± EMR have, however, become preferred minimally invasive ablative therapy for BE-related neoplasia due to poor efficacy of PDT.

Ductular and proliferative response of esophageal submucosal glands in a porcine model of esophageal injury and repair

Esophageal injury is a risk factor for diseases such as Barrett's esophagus (BE) and esophageal adenocarcinoma. To improve understanding of signaling pathways associated with both normal and abnormal repair, animal models are needed. Traditional rodent models of esophageal repair are limited by the absence of esophageal submucosal glands (ESMGs), which are present in the human esophagus. Previously, we identified acinar ductal metaplasia in human ESMGs in association with both esophageal injury and cancer. In addition, the SOX9 transcription factor has been associated with generation of columnar epithelium and the pathogenesis of BE and is present in ESMGs. To test our hypothesis that ESMGs activate after esophageal injury with an increase in proliferation, generation of a ductal phenotype, and expression of SOX9, we developed a porcine model of esophageal injury and repair using radiofrequency ablation (RFA). The porcine esophagus contains ESMGs, and RFA produces a consistent and reproducible mucosal injury in the esophagus. Here we present a temporal assessment of this model of esophageal repair. Porcine esophagus was evaluated at 0, 6, 18, 24, 48, and 72 h and 5 and 7 days following RFA and compared with control uninjured esophagus. Following RFA, ESMGs demonstrated an increase in ductal phenotype, echoing our prior studies in humans. Proliferation increased in both squamous epithelium and ESMGs postinjury with a prominent population of SOX9-positive cells in ESMGs postinjury. This model promises to be useful in future experiments evaluating mechanisms of esophageal repair.NEW & NOTEWORTHY A novel porcine model of injury and repair using radiofrequency ablation has been developed, allowing for reproducible injury to the esophagus to study repair in an animal model with esophageal submucosal glands, a key anatomical feature and missing in rodent models but possibly harboring progenitor cells. There is a strong translational component to this porcine model given the anatomical and physiological similarities between pigs and humans.

MicroRNA profile in neosquamous esophageal mucosa following ablation of Barrett’s esophagus

AIM

To investigate the microRNA expression profile in esophageal neosquamous epithelium from patients who had undergone ablation of Barrett’s esophagus.

METHODS

High throughput screening using TaqMan^® Array Human MicroRNA quantitative PCR was used to determine expression levels of 754 microRNAs in distal esophageal mucosa (1 cm above the gastro-esophageal junction) from 16 patients who had undergone ablation of non-dysplastic Barrett’s esophagus using argon plasma coagulation vs pretreatment mucosa, post-treatment proximal normal non-treated esophageal mucosa, and esophageal mucosal biopsies from 10 controls without Barrett’s esophagus. Biopsies of squamous mucosa were also taken from 5 cm above the pre-ablation squamo-columnar junction. Predicted mRNA target pathway analysis was used to investigate the functional involvement of differentially expressed microRNAs.

RESULTS

Forty-four microRNAs were differentially expressed between control squamous mucosa vs post-ablation neosquamous mucosa. Nineteen microRNAs were differentially expressed between post-ablation neosquamous and post-ablation squamous mucosa obtained from the more proximal non-treated esophageal segment. Twelve microRNAs were differentially expressed in both neosquamous vs matched proximal squamous mucosa and neosquamous vs squamous mucosa from healthy patients. Nine microRNAs (miR-424-5p, miR-127-3p, miR-98-5p, miR-187-3p, miR-495-3p, miR-34c-5p, miR-223-5p, miR-539-5p, miR-376a-3p, miR-409-3p) were expressed at higher levels in post-ablation neosquamous mucosa than in matched proximal squamous and healthy squamous mucosa. These microRNAs were also more highly expressed in Barrett’s esophagus mucosa than matched proximal squamous and squamous mucosa from controls. Target prediction and pathway analysis suggests that these microRNAs may be involved in the regulation of cell survival signalling pathways. Three microRNAs (miR-187-3p, miR-135b-5p and miR-31-5p) were expressed at higher levels in post-ablation neosquamous mucosa than in matched proximal squamous and healthy squamous mucosa. These miRNAs were expressed at similar levels in pre-ablation Barrett’s esophagus mucosa, matched proximal squamous and squamous mucosa from controls. Target prediction and pathway analysis suggests that these microRNAs may be involved in regulating the expression of proteins that contribute to barrier function.

CONCLUSION

Neosquamous mucosa arising after ablation of Barrett’s esophagus expresses microRNAs that may contribute to decreased barrier function and microRNAs that may be involved in the regulation of survival signaling pathways.

Barrett's esophagus: lessons from recent clinical trials

Data from recent studies cast doubt on former recommendations on diagnosis and management of Barrett’s esophagus. Based on latest research findings several Gastroenterological Associations actualized their guidelines and international experts compiled consensus statements as practical help for clinicians. In this review we discuss recent trials and their impact on clinical practice, current recommendations and persisting controversies in Barrett’s esophagus.