Simultaneous use of endoscopic resection and radiofrequency ablation is not safe in an esophageal porcine model

Radiofrequency vapor ablation for Barrett's esophagus: feasibility, safety and proof of concept in a stepwise study with in vitro, animal, and the first in-human application

INTRODUCTION

The Radiofrequency Vapor Ablation (RFVA) System (AquaMedical, Inc., Santa Ana, CA) is a novel ablation system for eradication of Barrett's esophagus, that generates vapor at 100 °C using an RF electrode located in the catheter tip. We performed in-vitro dosimetry studies and the first in-human feasibility study.

METHODS

The system includes an RFVA generator with syringe pump and a through-the-scope-catheter. The RFVA system was tested in-vitro (lean-beef and porcine study) and ablation depth was compared to focal RFA. Two doses were selected for further in-vivo testing in dysplatic BE patients. Repeat endoscopy with histology was performed after 8 weeks to assess squamous conversion.

RESULTS

In porcine, RFVA 3-seconds was comparable to RFA, whereas RFVA 5-seconds produced slightly deeper ablation. We selected a conservative 1-second and 3-seconds for human study. Fifty-three ablations were successfully applied in 15 patients with no adverse events. Follow-up endoscopy showed a median squamous conversion of 55 % (IQR 33 - 74) and 98 % (56 - 99) for 1 and 3-seconds, respectively.

CONCLUSIONS

In this 3-phase study with lean-beef, porcine and the first in-human application, the RFVA system was feasible for esophageal ablation and successfully and safely converted targeted BE areas into squamous epithelium.

Extension of early esophageal squamous cell neoplasia into ducts and submucosal glands and the role of endoscopic ablation therapy

BACKGROUND AND AIMS

Early esophageal squamous cell neoplasia (ESCN) is preferably treated with en-bloc endoscopic resection. Ablation might be an alternative for flat ESCN, but ESCN extension along the epithelial lining of ducts and submucosal glands (SMGs) might jeopardize ablation efficacy. Clinical studies suggest that local recurrence might arise from such buried ESCN niches after ablation. We studied human endoscopic resection specimens of ESCN to quantify ESCN extension into ducts/SMGs and performed a prospective porcine study to evaluate the depth of radiofrequency ablation (RFA) and CryoBalloon ablation (CBA) into ducts/SMGs.

METHODS

Endoscopic submucosal dissection specimens of flat-type ESCN from a Japanese (n = 65) and Dutch cohort (n = 14) were evaluated for presence and neoplastic involvement of ducts/SMGs. Twenty-seven pigs were treated with circumferential RFA (c-RFA; n = 4), focal CBA (n = 20), and focal RFA (n = 3) with 4, 60, and 9 treatment areas, respectively. After prespecified survival periods (0 hours, 8 hours, 2 days, 5 days, and 28 days), treatment areas were evaluated for uniformity and depth of ablation and affected SMGs.

RESULTS

Neoplastic extension in ducts/SMGs was observed in most lesions: 58% (38/65) in the Japanese and 64% (9/14) in the Dutch cohort. In the animal study, 33% of SMGs (95% confidence interval, 28-50) were not affected after c-RFA, although the overlying epithelium was ablated. Focal RFA and CBA resulted in uniform ablations with effective treatment of all SMGs.

CONCLUSIONS

ESCN extends into ducts/SMGs in most patients. In an animal model, focal RFA and CBA effectively ablated SMGs, whereas c-RFA inadequately ablated SMGs. Given this potential reason for recurrence, endoscopic resection should remain the standard of care.

Endoscopic resection combined with the Cryoballoon focal ablation system in the porcine normal esophagus: a preclinical study

BACKGROUND

The Cryoballoon focal ablation system (CbFAS) for dysplastic Barrett's esophagus is simple, time-saving and has high therapeutic efficacy. This study aimed to evaluate the technical feasibility and tissue damage with combination therapy of endoscopic resection (ER) and CbFAS in porcine models.

METHODS

Three pigs (A, B, and C) were included, and all ER procedures were performed by endoscopic mucosal resection using the Cap method (EMR). Combination therapy for each pig was performed as follows: (a) CbFAS was performed for a post-EMR mucosal defect for Pig A; (b) CbFAS for post-EMR scar for Pig B, and (c) EMR for post-CbFAS scar for Pig C. All pigs were euthanized at 32 days after the initial procedure, and the tissue damage was evaluated.

RESULTS

All endoscopic procedures were followed as scheduled. None of the subjects experienced anorexia, rapid weight loss, bleeding, and perforation during the observation period. They were euthanized at 32 days after the initial endoscopic procedure. On histological assessment, there was little difference between the tissue that was treated with CbFAS alone and that treated with CbFAS in combination with ER.

CONCLUSION

Combination therapy with ER and CbFAS can be technically feasible, and its outcome was not significantly different from CbFAS alone in terms of tissue damage.

Single-Step Treatment with Limited Endoscopic Resection and Cryoballoon Ablation Is Feasible and Safe in an Esophageal Porcine Model

BACKGROUND

Treatment of Barrett's neoplasia consists of two steps: endoscopic resection of visible lesions with subsequent ablation of remaining Barrett's epithelium. However, extensive resection might hamper subsequent ablation due to stenosis. Combining both modalities in one session therefore offers potential advantages. Single-step treatment with radiofrequency ablation and resection appeared to be unsafe.

AIMS

To evaluate feasibility and safety of single-step treatment with cryoballoon ablation and endoscopic resection.

METHODS

Two single-step treatment regimens (15 treatment areas per regimen) were evaluated: (1) CRYO-EMR: four side-by-side focal ablations of 10 seconds followed by resection in the treated area; (2) EMR-CRYO: resection followed by 10-s ablation targeted on the resection wound. Primary outcome for both regimens was safety (perforations, clinically relevant strictures) and for CRYO-EMR also feasibility of resection and histopathological evaluation. Secondly, all CRYO-EMR and esophageal resection specimens were histopathologically evaluated.

RESULTS

Six female pigs were treated (five treatment areas per animal). During 28 days of follow-up, no perforations or clinically relevant stenosis occurred. All resections were technically successful. For all CRYO-EMR specimens, histopathological evaluation was feasible with ablation effects present throughout all layers, while the architecture requisite for histopathological analysis remained intact. After 28 days, histopathological evaluation of the esophagi was performed. For EMR-CRYO, post-treatment fibrosis was present throughout the submucosa. The muscularis propria was the deepest layer involved for CRYO-EMR.

CONCLUSIONS

Single-step treatment with limited endoscopic resection and cryoballoon ablation is feasible and safe in a porcine model and justifies further evaluation in a clinical trial.

Workload, Recurrence, Quality of Life and Long-term Efficacy of Endoscopic Therapy for High-grade Dysplasia and Intramucosal Esophageal Adenocarcinoma

OBJECTIVE

To review the workload, type and frequency of recurrence, long-term quality of life (QOL), and late oncologic outcomes with endoscopic therapy.

BACKGROUND

The short-term oncologic efficacy of endoscopic resection (ER) and ablation for patients with high-grade dysplasia (HGD) or intramucosal adenocarcinoma (IMC) is well-established in the literature.

METHODS

A retrospective chart review was performed of the initial 40 patients who had endoscopic therapy from 2001 to 2010 at 1 center by 1 physician.

RESULTS

Initial pathology was HGD in 22 and IMC in 18 patients, but 9 patients (41%) with HGD progressed to invasive cancer during endotherapy. The median follow-up was 82 months. Four patients had an esophagectomy, and in the remaining 36 patients, 70 ERs and 111 ablations were performed. The median number of endoscopic sessions was 4 in patients with short segment compared with 7 in patients with long-segment Barrett's. Complete resolution of intestinal metaplasia (CRIM) was achieved in 30 patients (83%) at a median of 21 months. In 18 patients (60%), CRIM was maintained, whereas 12 patients developed recurrence at a median of 14 months. Additional endotherapy (n = 11) led to CRIM again in 10 patients (83%). There were no cancer deaths when CRIM was achieved. Overall survival with endotherapy was 73% at 5 years and 67% at 10 years. Quality of life (QOL) was below population means in 4 of 8 areas, but alimentary satisfaction was good after endotherapy.

CONCLUSIONS

Endotherapy is successful in most patients, but multiple sessions are usually required and disease progression can occur. Once CRIM is achieved, recurrence is common and mandates continued endoscopic follow-up. QOL is impaired with endotherapy, but alimentary satisfaction and oncologic outcomes support esophageal preservation with endotherapy for patients with HGD or IMC.

Radiofrequency Ablation for Early Superficial Flat Esophageal Squamous Cell Neoplasia: A Comprehensive Review

Esophageal squamous cell carcinoma comprises the majority of esophageal carcinoma in the Eastern Asia. The need of early detection of precancerous neoplastic lesions and cancer has been necessitated due to the probability of progression to the advanced stage and its poor prognosis. In recent times, many endoscopic modalities have come into practice for early detection and treatment. Endoscopic radiofrequency ablation (RFA) has been recommended as an efficient therapy in treating the dysplastic mucosa in Barrett's esophagus (BE). Its potential in reversing neoplastic lesions in squamous epithelium has been gradually explored. This article is aimed at reviewing the current evidence regarding the use of RFA on esophageal squamous cell neoplasia.