Dirk W. Schölvinck

Treatment of Barrett's esophagus with a novel focal cryoablation device : a safety and feasibility study

BACKGROUND AND AIMS Currently, eradication of Barretts epithelium is preferably achieved using radiofrequency ablation (RFA) or spray cryoablation (SCA). However, both modalities suffer from drawbacks such as the need for sizing, multiple deployment steps, large controller units (RFA), imprecise dosing and need for gas-venting (SCA). The new Cryoballoon Focal Ablation System (CbFAS) may address these limitations. This study assessed the safety, feasibility, and dose response of the CbFAS in patients with flat Barretts epithelium with or without dysplasia. PATIENTS AND METHODS In this multicenter, prospective non-randomized trial, 39 patients were each treated with one or two ablations of 6, 8, or 10 seconds. Symptoms were assessed immediately and 2 days post-cryoablation. Follow-up endoscopy was performed 6-8 weeks post-procedure to assess response. Outcome parameters were incidence of adverse events, pain, esophageal stricture formation, and ablation response by cryogen dose. RESULTS Of 62 ablations, 56 (10 with 6 seconds, 28 with 8 seconds, 18 with 10 seconds) were successfully performed. Six ablations failed because of device malfunction (n=3) and procedural or anatomic issues (n=3). Median procedure time was 7 minutes (interquartile range [IQR] 4-10). No major adverse events occurred; six patients experienced a minor mucosal laceration requiring no intervention. Mild pain was reported by 27% of patients immediately after cryoablation and by 14% after 2 days. No strictures were evident at follow-up.  Full squamous regeneration was seen in 47 treated areas (6 [60%] of the 6-second areas; 23 [82%] of the 8-second areas; 18 [100%] of 10-second areas). CONCLUSIONS Focal cryoablation of Barretts epithelium with the CbFAS is feasible and safe, resulting in squamous regeneration in the majority of patients.

Efficacy of the CryoBalloon Focal Ablation System for the eradication of dysplastic Barrett’s esophagus islands

Background and study aim Cryoablation can be used for the treatment of Barretts esophagus (BE). A recent dosimetry study, using the CryoBalloon Focal Ablation System (CryoBalloon), demonstrated that 10-second ablations result in complete eradication of BE. However, the efficacy of 10-second ablation in a larger cohort of patients has not been investigated, nor has the potential of precise targeting of specific areas. The aim of the study was to assess the efficacy and performance (i. e. targeting of BE islands) of a 10-second cryoablation using the CryoBalloon. Results A total of 30 patients were enrolled (worst pathology: low grade dysplasia in 14 [47 %], high grade dysplasia in 7 [23 %], early adenocarcinoma in 9 [30 %]). Of the 47 BE islands, 44 (94 %) were adequately targeted. Complete eradication of intestinal metaplasia and dysplasia was observed in 100 % of the completely ablated areas. No stenoses were observed. Conclusion Cryoablation of BE islands using the CryoBalloon is effective. BE islands were effectively targeted.

Erratum to: Management of patients with T1b esophageal adenocarcinoma: a retrospective cohort study on patient management and risk of metastatic disease.

Background Esophagectomy for submucosal (T1b) esophageal adenocarcinoma (EAC) is performed in order to optimize patient outcomes given the risk of concurrent lymph node metastases (LNM). However, not seldom, comorbidity precludes these patients from surgery. Therefore, the aim of our study was to assess the course of follow-up after treatment in submucosal EAC patients undergoing surgery versus conservative therapy and to evaluate the incidence of metastatic disease.

Simplified protocol for focal radiofrequency ablation using the HALO90 device: short-term efficacy and safety in patients with dysplastic Barrett’s esophagus

BACKGROUND AND STUDY AIMS The standard protocol for focal radiofrequency ablation (RFA) of Barretts esophagus comprises two applications of radiofrequency energy, cleaning of the ablated areas and catheter, and two further applications (2 × 15 J/cm(2) - cleaning - 2 × 15 J/cm(2)). A simplified protocol (3 × 15 J/cm(2), no cleaning) proved noninferior to standard protocol for individual islands of Barretts esophagus, but may be associated with higher stenosis rates when applied circumferentially and sequentially over time. We evaluated the efficacy and safety of the above mentioned simplified protocol. PATIENTS AND METHODS Barretts esophagus patients undergoing focal RFA using the simplified protocol in four tertiary referral centers were retrospectively included. During each focal ablation, the gastroesophageal junction (GEJ) was ablated circumferentially in addition to Barretts esophagus islands or tongues. Sessions continued at 8 to 12-week intervals until complete resolution of Barretts esophagus. Primary outcome parameters comprised complete remission of dysplasia and of intestinal metaplasia, and stenosis requiring dilation. RESULTS 83 patients with dysplastic Barretts esophagus (median Prague classification C1M3) were enrolled; 66/83 (80 %) had endoscopic resection of a visible lesion before RFA. Intention-to-treat analysis showed complete remission of dysplasia in 78/83 (94 %) and of intestinal metaplasia in 72/83 (87 %). Stenosis requiring dilation developed in 9/83 (11 %), necessitating a median 2 dilation sessions (range 1 - 9), with ≥ 8 sessions in three patients. CONCLUSION A treatment algorithm incorporating the simplified protocol of 3 × 15 J/cm(2), with no cleaning, for all focal RFA sessions, appears effective. The associated number and severity of stenoses, however, raises safety concerns.

Detection of lesions in dysplastic Barrett’s esophagus by community and expert endoscopists

Background and aims Endoscopic treatment of Barretts esophagus (BE) consists of endoscopic resection of visible lesions followed by radiofrequency ablation (RFA) for any remaining flat BE. Because RFA is only justified in flat BE, detection of neoplastic lesions (high grade dysplasia [HGD] and early adenocarcinoma [EAC]) is crucial. We hypothesized that the detection of visible lesions containing HGD or EAC would be superior in BE expert centers compared with community hospitals, thereby supporting centralization of therapy for BE-related neoplasia. Methods Patients referred with histologically proven HGD or EAC to two Dutch BE expert centers were included. Referral letters, and endoscopy and pathology reports were reviewed for the description of the BE, presence of lesions, and histopathological analysis of target and random tissue sampling. Primary outcome was the endoscopic detection rate of lesions containing histopathologically proven neoplasia (HGD and/or EAC) in community and expert centers. Results There were 198 patients referred from 37 community hospitals (median referral time 55 days [interquartile range 33 - 85]). Detection rates for visible lesions were 60 % in community centers (75 % in patients with a biopsy diagnosis of EAC, 47 % in HGD) and 87 % in expert centers (98 % in EAC, 75 % in HGD); P < 0.001. Even with HGD/EAC on random biopsies from the index endoscopy, the yield at repeat endoscopy was < 50 % in community hospitals. In 79 patients referred solely because of random biopsy results, a lesion requiring endoscopic resection or surgery was found in 76 % by the expert endoscopists. Conclusions Endoscopists at community hospitals detect neoplastic lesions at a significantly lower rate. These data support the value of BE expert centers for work-up and further treatment of BE.

Effects of Lugol staining on stenosis formation induced by radiofrequency ablation of esophageal squamous epithelium: a study in a porcine model

Preliminary data show higher stricture rates after radiofrequency ablation (RFA) for early esophageal squamous neoplasia compared with Barretts esophagus. We studied the effects of Lugol stain (LS) directly prior to RFA on stricture formation in squamous epithelium. Of 16 pigs, the distal half of the esophagus was LS, followed by circumferential RFA (single application 12 J/cm(2) ) in the unstained and stained esophagus. Pigs were euthanized at day 0 (n = 4), 3 (n = 4), or 28 (n = 8). Histology was evaluated in four areas: blank-control (no RFA, no LS), blank-RFA (no LS), LS+RFA, and LS-control (no RFA). Stenosis severity in LS+RFA and blank-RFA at 28 days was assessed by the ratio of the mucosal diameter at the RFA area to the diameter 2 cm proximal of this zone. Histology showed submucosal edema in 50% of LS+RFA versus 0% in blank-RFA. Severity and depth of inflammation (day 3) was equal in LS+RFA and blank-RFA. Severity and depth of fibrosis (day 28) appeared more severe in LS+RFA. Consequently, stenosis was present in 100% (LS+RFA) versus 12.5% (blank-RFA). The stenosis-severity ratio was 0.40 (interquartile range 0.29-0.45) in LS+RFA versus 0.73 (interquartile range 0.64-0.78) in blank-RFA (P = 0.012). Limitations of this study were the difference in uptake of LS between pigs and humans, the difference in esophageal anatomy between pigs and humans, and between the proximal and distal esophagus within pigs. In conclusion, in the porcine squamous esophagus, stenosis rate and severity after RFA increased when preceded by LS. LS may be contributing in the altered response of squamous epithelium to RFA as compared with Barretts esophagus.

Balloon-based esophageal cryoablation with a novel focal ablation device: dose-finding and safety in porcine and human models

The new Cryoballoon Focal Ablation System (CbFAS), a through-the-scope catheter with battery-powered handle that delivers cryogenic fluid into an inflated balloon, differs from current cryotherapy methods used for treatment of Barretts epithelium. In this dose-finding study, short- and long-term histopathological effects and safety of the CbFAS were evaluated. Cryoablations with (supra)therapeutic durations (4-24 seconds) were performed in pigs that survived for 12 or 48 hours or 4 or 28 days. Next, cryoablations (durations based on animal data) were performed in normal mucosa of esophageal cancer patients scheduled to undergo esophagectomy. The outcome parameters, the occurrence of any bleeding or perforation, the histological presence of edema, inflammation, and necrosis throughout the esophageal wall layers, were evaluated. A total of 60 cryoablations were performed in 11 pigs. 48 hour cryoablations with therapeutic durations (4-10 seconds) resulted in edema/inflammation as deep as the serosa and necrosis ranging from submucosa to serosa with a median depth of 3.2 mm. In 4 day cryoablations this was in the serosa, and muscularis tunica to serosa at a median depth of 4.5 mm, respectively. No necrosis or inflammation remained after 28 days, not even after supratherapeutic cryoablation (12-24 seconds). No acute or delayed bleeding or perforation was observed. Next, eight 6-second cryoablations were performed in four patients. Direct postablation mucosal necrosis was observed; after 4 days necrosis and inflammation was limited to the submucosa. CbFAS cryoablation penetrates deeply into the esophageal wall layers resulting in severe early ablation. After 4 weeks, little injury and no fibrosis remain, even after supratherapeutic durations of administration, suggesting that CbFAS combines deep ablation with a potentially favorable safety profile.

Circumferential cryoablation in a strictured esophagus: a feasibility and dose-finding study in a porcine model after inducing stenosis by endoscopic mucosal resection.

In the treatment of early esophageal Barretts neoplasia, radiofrequency ablation may be hindered by stenosis due to prior endoscopic resection (ER). The flexible balloon-based circumferential CryoBalloon Ablation System (CBAS) may overcome this problem by the conformability of the compliant balloon which might enable circumferential cryoablation in a stenosis. The aim of the current study was to evaluate the feasibility of the CBAS as well as the dose-response effect of cryoablation in a strictured esophagus model. In six pigs, a stenosis was induced by ER (3 cm in length, 75% of circumference) in the proximal, mid, and distal esophagus. After 28 days, cryoablation with the CBAS was performed, with the length of ablation time (6, 8, or 10 seconds) randomly assigned per stricture location within the esophagus. Four days post-ablation, the esophagi were harvested for histopathological assessment of the percentage of the total circumference affected by cryoablation and the maximum depth of necrosis. At 28 days, all 18 ER areas had transformed into strictures with ±50% of its original diameter remaining. In 9 of 18 strictures, more than one attempt for cryoablation was necessary due to displacement of the balloon. Histopathological evaluation showed a wide range in circumferential uniformity (0-100%) and maximum necrosis depth (epithelium to external proper muscle layer) of cryoablation, both independent of ablation times. Deepest ablation effects were seen at the center of the resection-induced scar. This first generation CryoBalloon Focal Ablation System was not feasible for ablation within severe stenoses, since it results in inconsistent circumferential uniformity of cryoablation with subsequent differences in depth of ablation. Further research with a next generation CBAS in a more realistic stricture model is warranted.