Endoscopic spray cryotherapy for esophageal cancer: safety and efficacy

Endoscopic spray cryotherapy for dysphagia palliation in esophageal cancer: Systematic review and meta-analysis

Background and study aims Endoscopically delivered liquid nitrogen spray cryotherapy is reported to be a safe and possibly more effective strategy for dysphagia palliation in patients with advanced esophageal cancer. This systematic review and meta-analysis aimed to pool all available data to evaluate the impact of this treatment modality. Methods Electronic databases (PubMed, Embase, and Cochrane Library) from January 2005 through June 2023 were searched for studies evaluating endoscopically delivered liquid nitrogen spray cryotherapy for dysphagia palliation in patients with advanced esophageal cancer. Pooled proportions were calculated using random-effects (DerSimonian-Laird) model. Results From an initial 895 studies, data were extracted and analyzed from five studies comprising a total of 230 patients that met inclusion criteria. In this pooled analysis, dysphagia improved or did not deteriorate in 81.40% of patients (95% confidence interval [CI] 73.75-87.99). Significant improvement in dysphagia was reported by 55.19% of patients (95% CI 29.62-79.37). An alternate method of dysphagia palliation despite spray cryotherapy was required in 18.78% of patients (95% CI 8.09-32.63) with 10.56% (95% CI 2.53-23.18) requiring esophageal stents. The weighted mean number of spray cryotherapy sessions per patient was 3.37 (95% CI 2.55-4.18). The pooled major adverse event rate was 3.26% (95% CI 0.15-10.14). Conclusions Endoscopic liquid nitrogen spray cryotherapy can effectively and safely treat dysphagia in esophageal cancer. It can be considered an option for dysphagia palliation in centers with expertise and equipment.

Endoscopic Palliative Therapies for Esophageal Cancer

Endoscopic palliation of dysphagia for patients with inoperable esophageal cancer is complex, highly dependent on local expertise, and best done in a multidisciplinary fashion. Systemic therapy is the standard of care because it has been shown to improve survival. Esophageal stenting has traditionally been the most used endoscopic modality. Some modalities such as laser and photodynamic therapy are rarely used. There has been an increasing amount of data on cryotherapy, especially for patients with mild-to-moderate dysphagia on systemic chemotherapy. This article will discuss the latest evidence guiding the palliation of esophageal cancer.

Cryogenic Media in Biomedical Applications: Current Advances, Challenges, and Future Perspectives

This paper explores the crucial role of cryogenic mediums in driving breakthroughs within the biomedical sector. The objective was to investigate, critically discuss, and present the current knowledge and state-of-the-art practices, along with the challenges and perspectives of the most common applications. Through an extensive literature review, this work aims to supplement existing research, offering a comprehensive and up-to-date understanding of the subject. Biomedical research involving cryogenic mediums is advancing on multiple fronts, including the development of advanced medical technologies, clinical treatments for life-threatening conditions, high-quality biospecimen preservation, and antimicrobial interventions in industrial food processing. These advances open new horizons and present cutting-edge opportunities for research and the medical community. While the current body of evidence showcases the impressive impact of cryogenic mediums, such as nitrogen, helium, argon, and oxygen, on revolutionary developments, reaching definitive conclusions on their efficiency and safety remains challenging due to process complexity and research scarcity with a moderate certainty of evidence. Knowledge gaps further underline the need for additional studies to facilitate cryogenic research in developing innovative technological processes in biomedicine. These advancements have the potential to reshape the modern world and significantly enhance the quality of life for people worldwide.

Bronchial balloon dilatation combined with cryotherapy for tuberculous cicatricial central airway stenosis, with Adobe Photoshop for the degree measurement: A multicenter, retrospective study

Objective

To explore bronchial balloon dilation (BD) combined with cryotherapy and Photoshop (PS)-base image processing technology in the interventional treatment of tuberculous cicatricial central airway stenosis (CCAS).

Methods

This multicenter, retrospective study analyzed the clinical data of patients with CCAS from six hospitals in Henan, China between June 2019 and October 2022.

Results

A total of 307 patients were included, including 152 (62 males) treated with BD alone and 155 (54 males) treated with BD combined with cryotherapy. One month after treatment, compared with the BD group, the total response rate [133 (85.8) vs. 105 (69.1), P < 0.001] and occurrence of restenosis at 1-monthaftertreatment [22 (14.2 %) vs. 47 (30.9 %), P < 0.001] in BD & cryotherapy group were significantly higher; furthermore, the inner diameter of the airway stenosis (8.1 ± 0.9 mm vs. 6.4 ± 1.5 mm, P < 0.001), the cross-sectional area of the airway stenosis (51.6 ± 7.8 mm2 vs. 33.1 ± 11.6 mm2, P < 0.001), FEV1 (5.26 ± 0.42 L vs. 4.32 ± 0.31 L, P < 0.001), and PEF (5.72 ± 0.36 L/s vs. 4.56 ± 0.42 L/s, P < 0.001) in BD & cryotherapy group showed significantly more improvements. Moreover, Pearson's correlation analysis showed significantly strong positive correlation (r = 0.818，P < 0.001) between the cross-sectional area of airway stenosis measured by PS-base image processing technology and the inner diameter of airway stenosis measured by chest CT.

Conclusion

BD combined with cryotherapy for the interventional treatment of CCAS might be superior to BD alone. PS-base image processing technology might be used as a supplement strategy for measuring the degree of central airway stenosis.

Cryotherapy for the Treatment of Tracheal Stenosis: A Systematic Review

Tracheal stenosis (TS) is an iatrogenic sequela after intubation or tracheostomy that is increasing despite technological improvement and skilled respiratory care in the ICU. According to the studies, the rate of TS varies from 10 to 22%, but only 1-2% of these stenoses are severe and present with inspiratory dyspnea that does not respond to medical management. Bronchoscopy is considered the most appropriate diagnostic test, and laser surgery and tracheobronchial stenting are the most commonly performed procedures for tracheal stenosis. However, alternative treatment options, including cryotherapy for inoperable patients, have yet to be studied widely. As the number of patients requiring ICU admission with mechanical intubation is increasing, it is crucial to acknowledge this complication and consider alternative management options. Here we present a review of the use of cryotherapy for post-intubation tracheal stenosis.  Pubmed, Cochrane, and EMBASE databases were inquired for studies performed using the keywords 'airway stricture' OR 'airway obstruction' AND 'post-intubation' OR 'post-extubation' OR 'tracheostomy' AND 'cryotherapy'. After the primary and secondary screening, five studies were included in the analysis.  We included 67 patients were included in the analysis, with a mean age of 50.2 (range: 42-55) years. Tracheal stenosis and subglottic stricture were the most common sites of stenosis. Twenty-nine patients were treated with cryotherapy only, while the rest 38 patients had cryotherapy followed by balloon dilation. After the intervention, 48 patients experienced improvement, five experienced no change in the symptoms, 13 patients were asymptomatic before the treatment, and one died. No complication was reported in 65 patients, with only minor complications reported in rest.  Although, there is no clear treatment protocol for patients with inoperable tracheal stenosis. Our review demonstrates that cryotherapy for inoperable tracheal stenosis can be an acceptable alternative treatment with significant clinical improvement. Additionally, cryotherapy has fewer adverse effects compared to other treatment options.

Interventional gastroenterology in oncology

Cancer is one of the foremost health problems worldwide and is among the leading causes of death in the United States. Gastrointestinal tract cancers account for almost one third of the cancer-related mortality globally, making it one of the deadliest groups of cancers. Early diagnosis and prompt management are key to preventing cancer-related morbidity and mortality. With advancements in technology and endoscopic techniques, endoscopy has become the core in diagnosis and management of gastrointestinal tract cancers. In this extensive review, the authors discuss the role endoscopy plays in early detection, diagnosis, and management of esophageal, gastric, colorectal, pancreatic, ampullary, biliary tract, and small intestinal cancers.

Optimal Management of Dysphagia in Patients with Inoperable Esophageal Cancer: Current Perspectives

The majority of patients with esophageal cancer are diagnosed at an advanced, incurable stage. Palliation of symptoms, specifically dysphagia, is a crucial component to improve quality of life and optimize nutritional status. Despite multiple available treatment modalities, there is not one accepted or recommended to be the preferred treatment option. Palliative management is often decided by a multidisciplinary team considering factors including local availability, preference, patient life expectancy, and symptom severity. Systemic therapies such as chemotherapy are the most commonly used palliative modalities. Oncologists are most familiar with radiation for dysphagia palliation, especially for advanced metastatic cancer patients with good performance status. One common approach used by endoscopist is self-expandable metal stents. This is preferred for patients with short-term survival and poor functional status as it provides rapid relief of dysphagia. Cryotherapy is a relatively new endoscopic ablative modality and appears to be a promising option for dysphagia palliation, but more data is needed for wider adoption. This review summarizes the current literature on endoscopic and non-endoscopic treatment options for malignant dysphagia.

Endoscopic Management of Esophageal Cancer

Advances in technology and improved understanding of the pathobiology of esophageal cancer have allowed endoscopy to serve a growing role in the management of this disease. Precursor lesions can be detected using enhanced diagnostic modalities and eradicated with ablation therapy. Furthermore, evolution in endoscopic resection has provided larger specimens for improved diagnostic accuracy and offer potential for cure of early esophageal cancer. In patients with advanced esophageal cancer, endoluminal therapy can improve symptom burden and provide therapeutic options for complications such as leaks, perforations, and fistulas. The purpose of this review article is to highlight the role of endoscopy in the diagnosis, treatment, and palliation of esophageal cancer.

Cryoballoon ablation as salvage therapy after nonradical resection of a high-risk T1b esophageal adenocarcinoma: a case report

Although esophagectomy with or without (neo)adjuvant chemoradiation therapy is the current standard of care for patients with early esophageal adenocarcinoma with high-risk features or after nonradical endoscopic resection of an early esophageal adenocarcinoma, not all patients are eligible for surgery due to varying reasons. In these patients, cryoballoon ablation may serve as an alternative treatment option considering the potential of deeper tissue ablation as compared to heat-based ablation techniques. We report the first case in which cryoballoon ablation was successfully performed as salvage therapy with a curative intent for positive deep resection margins after an incomplete endoscopic resection of a recurrent early esophageal adenocarcinoma.

Endoscopic cryotherapy: Indications, techniques, and outcomes involving the gastrointestinal tract

Endoscopic cryotherapy is a technique utilized for the ablation of target tissue within the gastrointestinal tract. A cryotherapy system utilizes the endoscopic application of cryogen such as liquid nitrogen, carbon dioxide or liquid nitrous oxide. This leads to disruption of cell membranes, apoptosis, and thrombosis of local blood vessels within the target tissue. Several trials utilizing cryotherapy for Barrett's esophagus (BE) with variable dysplasia, gastric antral vascular ectasia (GAVE), esophageal carcinoma, radiation proctitis, and metastatic esophageal carcinomas have shown safety and efficacy. More recently, liquid nitrogen cryotherapy (cryodilation) was shown to be safe and effective for the treatment of a benign esophageal stricture which was refractory to dilations, steroid injections, and stenting. Moreover, liquid nitrogen cryotherapy is associated with less post procedure pain as compared to radiofrequency ablation in BE with comparable ablation rates. In patients with GAVE, cryotherapy was found to be less tedious as compared to argon plasma coagulation. Adverse events from cryotherapy most commonly include chest pain, esophageal strictures, and bleeding. Gastric perforations did occur as well, but less often. In summary, endoscopic cryotherapy is a promising and growing field, which was first demonstrated in BE, but the use now spans for several other disease processes. Larger randomized controlled trials are needed before its role can be established for these different diseases.

Spray cryotherapy prevents need for palliative stenting in patients with esophageal cancer-associated dysphagia

BACKGROUND

Dysphagia is the most common symptom in advanced esophageal cancer patients. Esophageal stent placement (SP) is a common palliation method but can be associated with significant morbidity. Limited data exist regarding the ability of spray cryotherapy (SC) prolong time to SP.

METHODS

A Mayo Clinic (Rochester, MN) patient database was reviewed for cases with a SC indication of esophageal cancer palliation from 2007-2019. Procedures were performed using a liquid nitrogen SC system to apply 2-5 separate 20 second freeze and 60 second thaw cycles based on tumor characteristics. Primary outcome was time to subsequent palliative SP.

RESULTS

Of 56 patients (71.4% male, mean age 77.8 ± 10.2 years) who underwent a total of 199 SC sessions (mean 3.6 ± 2.7, range 1-12 per patient), 41 had adenocarcinoma and 15 squamous cell carcinoma (SCC). Overall, 13 patients underwent subsequent SP within a mean duration of 15.7 ± 11.0 months over a mean follow-up duration of 25.6 ± 29.4 months. Treatment did produce stenosis in 16 patients, who required dilation within a mean period of 193.1 ± 294.1 days; notably, 10 patients had a history of preceding malignant strictures requiring dilation. Two patients experienced bleeding requiring transfusion, whereas 1 experienced perforation at the start of SC. Prior chemotherapy and/or radiation was not associated with developing an SC-related complication (risk ratio (RR) 1.5; 95% CI 0.6-3.7, P > 0.4).

CONCLUSIONS

SC appears to be an effective and safe modality to palliate esophageal cancer in appropriate candidates. Majority of patients who undergo SC avoid the need for future SP. If patients eventually require SP, they are able to, on average, defer stenting for >1 year from SC initiation.

The role of ablation in the treatment of dysplastic Barrett's esophagus

Endoscopic eradication therapy for Barrett's esophagus has been established as an effective management strategy for patients with Barrett's esophagus with dysplasia and early esophageal cancer. Among the endoscopic therapies, ablation techniques such as radiofrequency ablation and cryoablation are effective primary treatment interventions with acceptable low complication rates forming the spectrum of a multimodal approach. Appropriate selection of patients, high-definition endoscopic evaluation, and dedicated histological assessment are important cornerstones to help navigate to the best effective treatment method. Carefully structured surveillance programs and preventive measures will be needed to provide long-term durability for maintaining complete remission.

Cryoballoon ablation for treatment of patients with refractory esophageal neoplasia after first line endoscopic eradication therapy

Background and study aims  Cryoablation with the Cryoballoon device is a novel ablative therapy that uses cycles of freezing and thawing to induce cell death. This single-center prospective study evaluated the feasibility of the focal cryoablation device for the treatment of areas of refractory esophageal neoplasia in patients who had undergone first line endoscopic eradication therapy (EET). Complete remission of dysplasia (CR-D) and complete remission of intestinal metaplasia (CR-IM) at first follow-up endoscopy, durability of disease reversal, rates of stenosis and adverse events were studied. Patients and methods  Eighteen cases were treated. At baseline, nine patients had low-grade dysplasia (LGD), six had high-grade dysplasia (HGD) and three had intramucosal carcinoma (IMC). Median length of dysplastic Barrett's esophagus (BE) treated was 3 cm. The median number of ablations per patient was 11. Each selected area of visible dysplasia received 10 seconds of ablation. One session of cryoablation was performed per patient. Biopsies were performed at around 3 months post-ablation. Results  CR-D was achieved in 78 % and CR-IM in 39 % of patients. There were no device malfunction or adverse events. Stenosis was noted in 11 % of cases. At a median follow up of 19-months, CR-D was maintained in 72 % of patients and CR-IM in 33 %. Conclusions  Cryoablation appears to be a viable rescue strategy in patients with refractory neoplasia. It is well tolerated and successful in obtaining CR-D and CR-IM in patients with treatment-refractory BE. Further trials of dosimetry, efficacy and safety in treatment-naïve patients are underway.

Liquid nitrogen spray cryotherapy-based multimodal endoscopic management of dysplastic Barrett's esophagus and early esophageal neoplasia: retrospective review and long-term follow-up at an academic tertiary care referral center

BACKGROUND

Endoscopic eradication therapy of dysplastic Barrett's esophagus (BE) and early esophageal neoplasia has emerged as an effective treatment option. Data for the role of spray cryotherapy (SCT) in this setting is relatively limited.

OBJECTIVE

To evaluate the safety and long-term outcomes of SCT-based multimodal therapy in the management of dysplastic BE and early esophageal neoplasia.

DESIGN

Single-center, retrospective, cohort study.

SETTING

Academic, tertiary care center between August 2008 and February 2019.

METHODS

A retrospective chart review was conducted of the prospectively maintained endoscopic cryotherapy database at our center. Fifty-seven patients were identified who underwent SCT treatment for dysplastic BE and esophageal or Gastro-esophageal (GE) junction adenocarcinoma during the study period. Primary outcome was complete eradication of intestinal metaplasia (CE-IM); secondary outcome was complete eradication of dysplasia (CE-D).

RESULTS

A total of 171 SCT procedures were performed in 57 patients. The majority of patients were male (89.5%) with long-segment BE (93%; mean segment length 6.2 cm). Complete follow-up data was available for 56 of these 57 patients. 43.9% (25/57) of patients underwent radiofrequency ablation (RFA) during the course of treatment (e.g. after initiating SCT). 33.3% of patients (19/57) were RFA failures prior to SCT. Additionally, 68.4% (39/57) of patients underwent endoscopic resection (EMR) prior to SCT as part of our multimodal approach to treatment of BE dysplasia/neoplasia. Four patients (7%) are currently undergoing active ablation and/or EMR treatment. CE-IM was achieved in 75% (39/52) of patients, and CE-D in 98.1% (51/52). Mean duration of overall follow-up was 4.8 years, with mean CE-IM durability of 2.6 years.

LIMITATIONS

Single-center only, retrospective study design.

CONCLUSION

SCT-based multimodal endoscopic therapy can achieve very high CE-IM (75%) and CE-D (>98%) rates in a high-risk population with esophageal dysplasia and/or neoplasia.

Management of Early-Stage Esophageal Adenocarcinoma by Endoscopic Spray Cryotherapy in the Setting of Portal Hypertension With Varices

The use of endoscopic spray cryotherapy to manage pathological conditions of the esophagus has become increasingly common. This mucosal ablation technique is believed to carry a lower risk of bleeding than other modalities. A 71-year-old woman and a 64-year-old man with portal hypertension and varices were diagnosed with invasive esophageal adenocarcinoma during routine variceal surveillance. Staging by endoscopic ultrasound and computed tomography was uT1N0M0 in both patients. They each underwent mucosal ablation using liquid nitrogen cryosprays with no adverse events. Both cancers completely resolved with 2 treatments, and neither patient has shown recurrence of neoplasia during follow-up observations for up to 2 years.

Treatment of early stage (T1) esophageal adenocarcinoma: Personalizing the best therapy choice

Esophagectomy is considered the primary form of management for esophageal adenocarcinoma (EAC); however, the surgery is associated with high rates of morbidity and mortality. For patients with early-stage EAC, endoscopic resection (ER) presents a potential curative treatment option that is less invasive and carries fewer risks procedure related risks, but it is associated with higher rates of cancer recurrence following the procedure. For some patients, age and comorbidities may prevent them from having esophagectomy as a treatment option, while other patients may be operative candidates but do not wish to undergo esophagectomy for a variety of reasons related to their values and preferences. Furthermore, while anxiety of cancer recurrence following ER may significantly diminish a patient’s quality of life (QOL), so might the morbidity surrounding esophagectomy. In addition to considering health status, patient preferences, and impacts on QOL, physicians and patients must also consider what treatments would be both beneficial and available to the patient, considering esophagectomy methods-minimally invasive vs open-or the use of chemoradiotherapy in addition to ER. Our article reviews and summarizes available treatment options for patients with early EAC and their potential effects on the health and wellbeing of patients based on the current data. We conclude with a request for more research of available options for early EAC patients, the conditions that determine when each option should be employed, and their effects not only on patient health but also QOL.

Successful Curative Cryoablation of an Esophageal Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The most common location of GIST is the stomach; however, occurrences of GIST in the esophagus are also possible albeit rare. Although the current standard of care for gastric and intestinal GIST involves surgery and tyrosine kinase inhibitors, this case report focuses on the potential of treating esophageal GIST through a novel means of cryoablation therapy.

Liquid Nitrogen Spray Cryotherapy in Treatment of Barrett's Esophagus, where do we stand? A Systematic Review and Meta-Analysis

Radiofrequency ablation (RFA) is the preferred treatment option for Barrett's esophagus (BE) to achieve complete eradication (CE) of dysplasia (D), and intestinal metaplasia (IM). Cryotherapy, using liquid nitrogen (LNC), is a cold-induced tissue-injury technique option for the ablation of BE. We conducted a systematic review and meta-analysis to assess the overall efficacy and safety of LNC in the treatment of BE. We conducted a search of multiple electronic databases and conference proceedings from inception through June 2018. The primary outcome was to estimate the pooled rates of CE-IM, CE-D, and CE-HGD. The secondary outcome was to estimate the risk of adverse events and recurrence of disease after LNC. Nine studies reported 386 patients who were treated with LNC. The pooled rate of CE-IM was 56.5% (95% CI 48.5-64.2, I2 = 47), pooled rate of CE-D was 83.5% (95% CI 78.3-87.7, I2 = 22.8), and pooled rate of CE-HGD was 86.5% (95% CI 64.4-95.8, I2 = 88.1). Rate of adverse events was 4.7%, and the risk of BE recurrence was 12.7%. On subgroup analysis, the pooled rate of CE-IM with LNC in patients who failed RFA was 58.4% (95% CI 47.2-68.8, I2 = 32.5), and the pooled rate of CE-D in the same population was 81.9% (95% CI 72.5-88.6, I2 = 5.9). CE-D rates with LNC are comparable to RFA while CE-IM rates appear to be lower than the rates achievable with RFA. CE-IM rate in RFA failed patients is 58.4% and thus LNC is a rescue option to consider in this population.

Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer

Approximately 85% of a single administered dose of 5-fluorouracil (5-FU) will be degraded by dihydropyrimidine dehydrogenase (DYPD). Studies have highlighted a link between the complete or partial loss of DYPD function and clinical responses to 5-FU; however, the underlying molecular basis of DPD deficiency remains poorly understood. Hence, the aim of the present study was to evaluate the prevailing hypothesis which suggests that overexpression of LINC00261 possesses the ability to modulate the methylation-dependent repression of DPYD, ultimately resulting in an elevation of the sensitivity of human esophageal cancer cells to 5-FU. LINC00261 levels were initially quantified, followed by analysis of DYPD methylation within the cancerous tissues collected from 75 patients diagnosed with esophageal cancer undergoing 5-FU-based adjuvant chemotherapy. In an attempt to determine the levels of LINC00261 related to the esophageal cancer cell resistance to 5-FU and to identify the interaction between the levels of LINC00261 and methylation of the DYPD promoter, esophageal cancer cells TE-1 and -5 were prepared, in which LINC00261 and the 5-FU-resistant TE-1 and -5 cells were overexpressed. The levels of LINC00261 were reduced among the cancerous tissues obtained from patients exhibiting resistance to 5-FU. Overexpression of LINC00261 was determined to dramatically inhibit proliferation and resistance to apoptosis among 5-FU-resistant TE-1 and -5 cells, whereas silencing of LINC00261 was determined to enhance proliferation and resistance to apoptosis among the TE-1 and -5 cells. DPYD, a confirmed target of LINC00261, displayed a greater incidence of DNA methylation among patient's sensitive to 5-FU. A key finding revealed that overexpressed LINC00261 could increase the methylation of the DPYD promoter through the recruitment of DNA methyltransferase (DNMT), which, in turn, acts to decrease DPYD activity in 5-FU-resistant TE-1 cells, whereas a reversible change was recorded once the demethylation reagent 5-aza-2'-deoxyctidine was employed to treat the 5-FU-resistant TE-1 cells. Taken together, the results of the study provided evidence emphasizing the distinct antitumor ability of LINC00261 in cases of esophageal cancer, which was manifested by overexpression of LINC00261 detected to increase the sensitivity of human esophageal cancer cells to 5-FU by mediating methylation-dependent repression of DPYD. Our study highlighted the potential of LINC00261 as a novel target capable of improving the chemotherapeutic response and survival of patients with esophageal cancer.-Lin, K., Jiang, H., Zhuang, S.-S., Qin, Y.-S., Qiu, G.-D., She, Y.-Q., Zheng, J.-T., Chen, C., Fang, L., Zhang, S.-Y. Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer.

Endoscopic foregut surgery and interventions: The future is now. The state-of-the-art and my personal journey

In this paper, I reviewed the emerging field of endoscopic surgery and present data supporting the contention that endoscopy can now be used to treat many foregut diseases that have been traditionally treated surgically. Within each topic, the content will progress as follows: "lessons learned", "technical considerations" and "future opportunities". Lessons learned will provide a brief background and update on the most current literature. Technical considerations will include my personal experience, including tips and tricks that I have learned over the years. Finally, future opportunities will address current unmet needs and potential new areas of development. The foregut is defined as "the upper part of the embryonic alimentary canal from which the pharynx, esophagus, lung, stomach, liver, pancreas, and part of the duodenum develop". Foregut surgery is well established in treating conditions such as gastroesophageal reflux disease (GERD), achalasia, esophageal diverticula, Barrett's esophagus (BE) and esophageal cancer, stomach cancer, gastric-outlet obstruction, and obesity. Over the past decade, remarkable progress in interventional endoscopy has culminated in the conceptualization and practice of endoscopic foregut surgery for various clinical conditions summarized in this paper. Regarding GERD, there are now several technologies available to effectively treat it and potentially eliminate symptoms, and the need for long-term treatment with proton pump inhibitors. For the first time, fundoplication can be performed without the need for open or laparoscopic surgery. Long-term data going out 5-10 years are now emerging showing extended durability. In respect to achalasia, per-oral endoscopic myotomy (POEM) which was developed in Japan, has become an alternative to the traditional Heller's myotomy. Recent meta-analysis show that POEM may have better results than Heller, but the issue of post-POEM GERD still needs to be addressed. There is now a resurgence of endoscopic treatment of Zenker's diverticula with improved technique (Z-POEM) and equipment; thus, patients are choosing flexible endoscopic treatment as opposed to open or rigid endoscopy options. In regard to BE, endoscopic submucosal dissection (ESD) which is well established in Asia, is now becoming more mainstream in the West for the treatment of BE with high grade dysplasia, as well as early esophageal cancer. In combination with all the ablation technologies (radiofrequency ablation, cryotherapy, hybrid argon plasma coagulation), the entire spectrum of Barrett's and related dysplasia and early cancer can be managed predominantly by endoscopy. Importantly, in regard to early gastric cancer and submucosal tumors (SMTs) of the stomach, ESD and full thickness resection (FTR) can excise these lesions en-bloc and endoscopic suturing is now used to close large defects and perforations. For treatment of patients with malignant gastric outlet obstruction (GOO), endoscopic gastro-jejunostomy is now showing better results than enteral stenting. G-POEM is also emerging as a treatment option for patients with gastroparesis. Obesity has become an epidemic in many western countries and is becoming also prevalent in Asia. Endoscopic sleeve gastroplasty (ESG) is now becoming an established treatment option, especially for obese patients with body mass index between 30 and 35. Data show an average weight loss of 16 kg after ESG with long-term data confirming sustainability. Finally, in respect to endo-hepatology, there are many new endoscopic interventions that have been developed for patients with liver disease. Endoscopic ultrasound (EUS)-guided liver biopsy and EUS-guided portal pressure measurement are exciting new frontiers for the endo-hepatologists.

Mucosal Ablation Techniques for Barrett's Esophagus and Early Esophageal Cancer

Patients with esophageal intestinal metaplasia, or Barrett's esophagus, may undergo dysplastic changes that eventually lead to invasive adenocarcinoma. Endoscopic therapy in the form of radiofrequency ablation and cryoablation has been described as a minimally invasive intervention to halt this sequence of dysplasia to carcinoma. Studies demonstrate that the use of radiofrequency ablation and cryoablation is highly successful at eradicating intestinal metaplasia and dysplasia and reducing the risk of disease progression. Furthermore, these modalities also may be used in combination with endoscopic mucosal resection, or as stand-alone therapy, for the treatment of intramucosal carcinoma, potentially circumventing the need for surgery.

Cryotherapy in the management of premalignant and malignant conditions of the esophagus

Endoscopic cryotherapy is a relatively new thermal ablative modality used for the treatment of neoplastic lesions of the esophagus. It relies on cycles of rapid cooling and thawing to induce tissue destruction with a cryogen (liquid nitrogen or carbon dioxide) leading to intra and extra-cellular damage. Surgical treatment was once considered the standard therapeutic intervention for neoplastic diseases of the esophagus and is associated with considerable rates of morbidity and mortality. Several trials that evaluated cryotherapy in Barrett’s esophagus (BE) associated neoplasia showed reasonable efficacy rates and safety profile. Cryotherapy has also found applications in the treatment of esophageal cancer, both for curative and palliative intent. Cryotherapy has also shown promising results as salvage therapy in cases refractory to radiofrequency ablation treatment. Cryoballoon focal ablation using liquid nitrogen is a novel mode of cryogen delivery which has been used for the treatment of BE with dysplasia and squamous cell carcinoma. Most common side effects of cryotherapy reported in the literature include mild chest discomfort, esophageal strictures and bleeding. In conclusion, cryotherapy is an effective and safe method for the treatment of esophageal neoplastic processes, ranging from early stages of low grade dysplasia to esophageal cancer.

Multifocal nitrous oxide cryoballoon ablation with or without EMR for treatment of neoplastic Barrett's esophagus (with video)

BACKGROUND AND AIMS

Endoscopic cryotherapy can eradicate neoplastic Barrett's esophagus (BE). A new contact cryoballoon focal ablation system (CbFAS)) freezes esophageal mucosa with nitrous oxide. We studied the safety and efficacy of CbFAS for complete eradication of neoplastic Barrett's esophagus.

METHODS

In a prospective clinical trial, consecutive BE patients with confirmed neoplasia (low-grade dysplasia [LGD], high-grade dysplasia [HGD], and/or intramucosal adenocarcinoma [ImCA]), at least 1 cm of BE, with or without prior ablation, were treated with a dose 10 seconds of spray per site. EMR was performed for nodular lesions. Treatments were repeated every 10 to 12 weeks until complete eradication, with a maximum of 5 treatments. Primary outcomes were complete eradication of all dysplasia (CE-D) and complete eradication of intestinal metaplasia (CE-IM) at 1 year (intention-to-treat analysis).

RESULTS

Forty-one assessable patients (22 treatment naive, 19 previously ablated) with LGD (n = 13), HGD (n = 23), or ImCA (n = 5) were treated. The median procedure time was 30 minutes. The median number of ablation procedures for CE-IM was 3 (interquartile range, 2-4). Overall 1-year CE-D and CE-IM rates were 95% and 88%, respectively. CE-D rate was significantly lower (67%) in those with ultra-long BE compared with those with <8 cm (100%, P = .02). Median pain scores were zero at day 1. Four patients (9.7%) developed mild dysphagia from stenoses requiring dilation. One patient on aspirin developed upper GI bleeding that did not require therapy.

CONCLUSIONS

Multifocal nitrous oxide cryotherapy using CbFAS is a promising, highly effective, and safe endoscopic treatment for primary or rescue therapy of BE-associated neoplasia and IM. (Clinical trial registration number: NCT02534233.).

Liquid nitrogen spray cryotherapy for dysphagia palliation in patients with inoperable esophageal cancer

BACKGROUND AND AIMS

Dysphagia is a debilitating symptom in patients with inoperable esophageal cancer that contributes to poor quality of life and worsening nutritional status. The 2 most commonly used palliative modalities for dysphagia are radiation therapy and esophageal stent placement. However, radiation therapy is limited by adverse events (AEs) and total dose, and stent placement has a high rate of AEs, including reflux, migration, and chest pain. A relatively new modality of liquid nitrogen endoscopic spray cryotherapy has been described as salvage when other options have been exhausted and when patients are no longer receiving systemic therapy. We evaluated the safety and efficacy of cryotherapy as the primary modality for relieving dysphagia in inoperable esophageal cancer including patients receiving systemic cancer therapy.

METHODS

This is a retrospective, multicenter, consecutive case series of 49 inoperable esophageal cancer patients undergoing palliative endoscopic cryotherapy at 4 specialized cancer centers from May 2014 to May 2016. The primary outcomes were change in dysphagia scores between pre- and postcryotherapy and AEs. Dysphagia was measured using a 5-point Likert scale: 0, no dysphagia; 1, dysphagia to solids; 2, dysphagia to semisolids; 3, dysphagia to liquids; 4, dysphagia to saliva.

RESULTS

Thirty-nine men and 10 women with a mean age of 58 years underwent a total of 120 cryotherapy treatments. The mean dysphagia score improved significantly from 2.4 precryotherapy to 1.7 postcryotherapy (improvement of .7 points; P < .001). Minor AEs were seen in 6 of 120 (5.0%) cryotherapy treatments (1 intraprocedural and 5 postprocedural). In addition, 1 patient developed a severe intraprocedural AE of dilation-related perforation, whereas another patient developed a benign stricture requiring dilation.

CONCLUSIONS

This preliminary retrospective study suggests that liquid nitrogen spray cryotherapy may be safe and effective for dysphagia palliation in inoperable esophageal cancer. Large prospective studies are needed to confirm these findings and identify patient and procedure characteristics associated with the greatest benefit.

Controversies in Endoscopic Eradication Therapy for Barrett's Esophagus

Advances in endoscopic eradication therapy for Barrett's Esophagus-associated neoplasia have resulted in a significant paradigm shift in the diagnosis and management of this complex disease. A robust body of literature critically evaluating outcomes of resection and ablative strategies has allowed gastroenterologists to make quality, evidence-based decisions for their patients. Despite this progress, there are still many unanswered questions and challenges that remain. Ultimately, identification of a cost-effective screening modality, biomarkers for risk stratification, and strides to eliminate post surveillance endoscopy after endoscopic eradication therapy are essential to reach our long-term goal for eradication of esophageal adenocarcinoma.

Efficacy of liquid nitrogen cryotherapy for Barrett's esophagus after endoscopic resection of intramucosal cancer: A multicenter study

BACKGROUND AND AIM

Liquid nitrogen cryotherapy (LNC) allows increased depth of ablation compared with radiofrequency ablation in Barrett's esophagus (BE). Expert centers may use LNC over radiofrequency ablation to ablate Barrett's esophagus after endoscopic resection of intramucosal cancer (IMCA). The aim of our study was to (1) evaluate the safety and efficacy of LNC ablation in patients with BE and IMCA and (2) to evaluate the progression to invasive disease despite therapy.

METHODS

This was a multicenter, retrospective study of consecutive patients with BE who received LNC following endoscopic mucosal resection (EMR) of IMCA. The outcomes evaluated were complete eradication of dysplasia and intestinal metaplasia and development of invasive cancer during follow up. The follow-up period was at least 1 year from initial LNC.

RESULTS

Twenty-seven patients were identified. The median Prague score was C3M5 (range C0M1-C14M14). After EMR+LNC, the median Prague score was C0M1 (range C0M0-C9M10); 22/27 patients (82%) achieved complete eradication of dysplasia after cryotherapy, and 19/27 patients (70%) achieved complete eradication of intestinal metaplasia. One out of 27 patients (4%) developed invasive cancer (disease beyond IMCA) over the study period.

CONCLUSION

Cryotherapy is an effective endoscopic tool for eradication of BE dysplasia after EMR for IMCA. Development of invasive cancer is low for this high-risk group.

Outcome of spray cryotherapy plus functional endoscopic sinus surgery on management of healing in nasal polyposis

BACKGROUND

Nasal Polyposis is a benign tumor in nasal or paranasal mucosa, which confronts difficulties in management of healing after treatments with surgery. The aim of this study was to evaluate the effects of Spray Cryotherapy (SCT) on management of healing in patients with nasal polyposis who undergone functional endoscopic sinus surgery.

METHODS

In this prospective, clinical trial study, we investigated on 40 patients with nasal polyposis that had indication for functional endoscopic sinus surgery. Patients were divided randomly into two parallel group; cryotherapy (with SCT) and placebo (without SCT). Evaluation of healing after surgery was evaluated with Lund-Mackay and The Sino-nasal outcome test (SNOT-22)-22 scores.

RESULT

Postoperatively, Lund-Mackay and SNOT-22 scores were significantly decreased in both groups, however these scores were significantly lower in cryotherapy group in comparison with placebo group. Also there were no reported serious side effects in both groups.

CONCLUSION

In this paper, we concluded that usage of SCT is an effective and safe method on management of healing and develops recovery rates in patients with nasal polyposis undergoing functional endoscopic sinus surgery.

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 Barrett's 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.

Safety and efficacy of endoscopic spray cryotherapy for esophageal cancer

Although surgery is traditionally the standard of care for esophageal cancer, esophagectomy carries significant morbidity. Alternative endoscopic therapies are needed for patients who are not candidates for conventional treatment. The objective of this study is to assess the safety, efficacy, and tolerability of spray cryotherapy of esophageal adenocarcinoma. This study includes patients with esophageal adenocarcinoma who had failed or were not candidates for conventional therapy enrolled retrospectively and prospectively in an open-label registry and patients in a retrospective cohort from 11 academic and community practices. Endoscopic spray cryotherapy was performed until biopsy proven local tumor eradication or until treatment was halted due to progression of disease, patient withdrawal or comorbidities. Eighty-eight patients with esophageal adenocarcinoma (median age 76, 80.7% male, mean length 5.1 cm) underwent 359 treatments (mean 4.4 per patient). Tumor stages included 39 with T1a, 25 with T1b, 9 with unspecified T1, and 15 with T2. Eighty-six patients completed treatment with complete response of intraluminal disease in 55.8%, including complete response in 76.3% for T1a, 45.8% for T1b, 66.2% for all T1, and 6.7% for T2. Mean follow-up was 18.4 months. There were no deaths or perforations related to spray cryotherapy. Strictures developed in 12 of 88 patients (13.6%) but were present before spray cryotherapy in 3 of 12. This study suggests that endoscopic spray cryotherapy is a safe, well-tolerated, and effective treatment option for early esophageal adenocarcinoma.

Efficacy and safety of liquid nitrogen cryotherapy for treatment of Barrett’s esophagus

AIM

To evaluate the efficacy and safety of liquid nitrogen cryotherapy as a primary or rescue treatment for BE, with and without dysplasia, or intramucosal adenocarcinoma (IMC).

METHODS

This was a retrospective, single-center study carried out in a tertiary care center including 45 patients with BE who was treatment-naïve or who had persistent intestinal metaplasia (IM), dysplasia, or IMC despite prior therapy. Barrett’s mucosa was resected via EMR when clinically appropriate, then patients underwent cryotherapy until eradication or until deemed to have failed treatment. Surveillance biopsies were taken at standard intervals.

RESULTS

From 2010 through 2014, 33 patients were studied regarding the efficacy of cryotherapy. Overall, 29 patients (88%) responded to cryotherapy, with 84% having complete regression of all dysplasia and cancer. Complete eradication of cancer and dysplasia was seen in 75% of subjects with IMC; the remaining two subjects did not respond to cryotherapy. Following cryotherapy, 15 patients with high-grade dysplasia (HGD) had 30% complete regression, 50% IM, and 7% low-grade dysplasia (LGD); one subject had persistent HGD. Complete eradication of dysplasia occurred in all 5 patients with LGD. In 5 patients with IM, complete regression occurred in 4, and IM persisted in one. In 136 cryotherapy sessions amongst 45 patients, adverse events included chest pain (1%), stricture (4%), and one gastrointestinal bleed in a patient on dual antiplatelet therapy who had previously undergone EMR.

CONCLUSION

Cryotherapy is an efficacious and safe treatment modality for Barrett’s esophagus with and without dysplasia or intramucosal adenocarcinoma.

Feasibility of liquid nitrogen cryotherapy after failed radiofrequency ablation for Barrett's esophagus

BACKGROUND AND AIM

Radiofrequency ablation (RFA) for dysplastic Barrett's esophagus (BE) is highly effective. RFA failures are infrequent but can be a challenging cohort to manage. There are limited data on the feasibility of liquid nitrogen cryospray ablation for complete eradication of dysplasia (CE-D) and/or intestinal metaplasia (CE-IM) after RFA has failed to achieve CE-IM in patients with dysplastic BE.

METHODS

This is a retrospective review from two medical centers of prospectively maintained databases looking at patients that underwent liquid nitrogen cryospray ablation for refractory intestinal metaplasia post failed RFA.

RESULTS

Eighteen patients were identified that met inclusion criteria. Eleven patients had persistent dysplasia and IM following RFA and seven had persistent non-dysplastic IM. More than 80% of patients were male with long-segment BE (median length 8 cm). Seventy two percent of patients with dysplasia achieved CE-D after cryotherapy. Fifty percent (9/18) of all RFA failures achieved CE-IM with cryotherapy. In comparison, RFA has a CE-IM of 78% in a less challenging treatment naïve cohort from a large-scale meta-analysis of 3802 patients. No adverse events occurred in our cohort.

CONCLUSION

Cryospray ablation is feasible and safe for achieving CE-D and CE-IM after RFA failure. The CE-D rates are high with cryotherapy in this population. CE-IM with cryotherapy is acceptable in this difficult-to-treat cohort when compared to CE-IM rates with RFA in dysplastic BE treatment naïve patients (50% vs 78%).

The Application of Liquid Nitrogen Spray Cryotherapy in Treatment of Bronchial Stenosis

OBJECTIVE

Spray cryotherapy (SCT), the application of liquid nitrogen in a noncontact form, has been demonstrated to have efficacy in treating various types of pathologic lesions of the airway when used as an adjunct with bronchoscopy. The purpose of the study was to evaluate the results of the use of bronchoscopic SCT on the airway in a single institution.

METHODS

We performed a retrospective review of data collected on all patients who underwent SCT to re-establish or improve airway patency in an 11-month period. Patients were classified based on the nature of their disease into benign or malignant. Demographic data, change in luminal patency, and clinical outcomes were recorded. The percent of stenosis was divided into grades according to the following classification: 1, ≤25%; 2, 26% to 50%; 3, 51% to 75%; and 4, ≥76%. We defined successful completion of treatment as obtaining a final patency of grade 1.

RESULTS

Twenty-two patients met inclusion criteria, with 45.5% (10 patients) having benign stenosis and 54.5% (12 patients) malignant. At initial bronchoscopic evaluation, the median grade of stenosis was 4 for malignant disease and 3.5 for benign disease. The median final posttreatment grade of stenosis was 2 for malignant disease and 1 for benign. The median improvement in grade of stenosis after treatment was 2 for both malignant and benign causes (Wilcoxon test, P = 0.92). Final patency of grade 1 was achieved in 42% of malignant stenosis and 80% of benign. Overall, 86.4% of patients had an improvement in grade of stenosis after treatment. The rate of morbidity was 4.5% (1/22) of all patients.

CONCLUSIONS

The median change in grade after treatment was 2 grades of improvement for both the benign and malignant groups. These results provide evidence that the use of SCT is equally efficacious for both types of stenosis with an expectation of overall improvement in luminal patency, offering a safe and effective method of achieving airway patency in a minimally invasive fashion. This study contributes to the small but growing body of literature supporting the use of SCT in benign and malignant disease.

Long-Term Survival in Stage IV Esophageal Adenocarcinoma with Chemoradiation and Serial Endoscopic Cryoablation

Esophageal cancer has a poor overall prognosis and is frequently diagnosed at a late stage. Conventional treatment for metastatic esophageal cancer involves chemotherapy and radiation. Local disease control plays a significant role in improving survival. Endoscopic spray cryotherapy is a novel modality that involves freezing and thawing to produce local ablation of malignant tissue via ischemic mechanisms. Spray cryotherapy has been shown to be effective, particularly for early T-stage, superficial esophageal adenocarcinomas. We present the case of a 72-year-old-male with locally recurrent stage IV esophageal adenocarcinoma and long-term survival of 7 years to date, with concurrent chemoradiation and serial cryoablation. He remains asymptomatic and continues to undergo chemotherapy and sequential cryoablation. The findings highlight the long-term safety and efficacy of cryotherapy in combination with chemoradiation, and suggest that cryoablation may have an additive role in the treatment of advanced stage esophageal adenocarcinoma.

Oesophageal cancer: Which treatment is the easiest to swallow? A review of combined modality treatments for resectable carcinomas

Oesophageal cancer is a relatively uncommon malignancy, but with poor prognosis. Despite several treatment options that are available, the 5-year survival rates rarely exceed 40%. This review discusses the main challenges of oesophageal cancer, the available treatment options, and the most effective treatment in terms of overall survival. The outcomes of clinical trials show that neo-adjuvant chemo-radiotherapy using cisplatin and 5-fluorouracil followed by oesophagectomy results in the greatest survival. However, the optimal chemotherapy and radiotherapy schedule remains unclear. There is no satisfactory treatment to date, particularly for patients with co-morbidities or advanced tumours.

Metered Cryospray™: a novel uniform, controlled, and consistent in vivo application of liquid nitrogen cryogenic spray

In this article, a novel cryotherapy approach using a uniform, controlled, and consistent in vivo application of liquid nitrogen (LN₂) spray as a Metered Cryospray^™ (MCS) process is described. Although MCS may be used for many potential clinical applications, this paper focuses on the development that led to the controlled and consistent delivery of radial LN₂ cryogen spray in order to generate a uniform circumferential effect and how the amount of MCS can be adapted to specifically ablate targeted diseases within a patient’s lumen such as an airway or esophagus.

Current status of spray cryotherapy for airway disease

The use of liquid nitrogen to treat skin and mucosal lesions is well understood in the dermatologic and gastrointestinal literature. Direct spray cryotherapy (SCT) in the airway has shown promising results in the treatment of esophageal premalignant and even invasive lesions. In the airway, several studies have shown it to be a safe, effective treatment for both benign and malignant disease. It is easily administered in the outpatient setting and can be repeated several times without undue side effects. In this article, we review the current literature on the use of SCT for the treatment of endobronchial lesions and also describe our own institutional experience of the use of SCT in the airway. The use of proper technique and airway venting is important in mitigating the complications of barotrauma from massive expansion of nitrogen upon conversion from the liquid to gaseous state. We also review some of the basic science principals behind the use of the cryotherapy to treat lesions in different tissues. We feel that SCT is a potential area for further research at both clinical and basic science level.

Large Bowel Obstruction following Endoscopic Spray Cryotherapy for Palliation of Rectal Cancer Bleeding

We report a unique case of a 79-year-old woman with metastatic rectal cancer who developed bowel obstruction following endoscopic cryotherapy with liquid nitrogen for palliation of bleeding in the rectum. She developed abdominal distention and pain following the procedure. Computed tomography of the abdomen revealed a paraumbilical hernia containing a segment of transverse colon resulting in partial bowel obstruction. It appears that the recurrent freeze-thaw cycles with poor decompression of the colon despite active venting suction during cryotherapy may have resulted in bowel distention and collapse, causing conformational changes resulting in partial bowel obstruction due to a paraumbilical hernia.

Endoscopic applications of cryospray ablation therapy-from Barrett’s esophagus and beyond

In the last decade, the treatment of dysplastic Barrett’s esophagus has evolved into primarily endoscopic therapy. Many techniques have become well-established to destroy or remove the mucosal lining of Barrett’s esophagus. One of the newest therapies, cryospray ablation, has become a modality to treat both dysplastic Barrett’s esophagus as well as esophageal carcinoma. In endoscopic applications, the cryogen used is either liquid nitrogen or carbon dioxide which causes tissue destruction through rapid freeze-thaw cycles. Unlike other endoscopic ablation techniques, its unique mechanism of action and depth of tissue injury allow cryoablation to be used effectively in flat or nodular disease. It can be combined with other modalities such as endoscopic mucosal resection or radiofrequency ablation. Its esophageal applications stem well-beyond Barrett’s into ablation of early carcinoma, palliative debulking of advanced carcinoma and reduction of tumor ingrowth into stents placed for dysphagia. Although there are fewer reported studies of endoscopic cryoablation in the literature compared to other endoscopic ablation methods, emerging research continues to demonstrate its efficacy as a durable ablation technology with a variety of applications. The aim of this review is to examine the pathophysiology of endoscopic cryospray ablation, describe its outcomes in Barrett’s with dysplasia and esophageal carcinoma, and examine its role in other gastrointestinal applications such as hemostasis in the stomach and rectum.

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 Barrett's 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.

Management of Barrett's esophagus: From screening to newer treatments

Barrett's esophagus is a premalignant condition of the esophagus in which the squamous epithelium of the lower end of the esophagus is replaced with columnar epithelium. Since the incidence of esophageal adenocarcinoma is on the rise, the major gastroenterology societies have come up with their recommendations for screening and surveillance. Specific factors like obesity, white race, age over 50 years, early age of onset of GERD, smoking and hiatal hernia have been identified as increasing the risk of Barrett's esophagus and adenocarcinoma. The diagnosis requires both endoscopic identification of columnar-lined mucosa and histological confirmation with biopsy. Most medical societies recommend screening people with GERD and other risk factors with endoscopy, but other alternatives employing less invasive methods are currently being studied. Surveillance strategies vary depending on the endoscopic findings and the Seattle biopsy protocol with random 4-quadrant sampling is recommended. Biomarkers have shown promising results, but more studies are needed in the future. White light endoscopy is the standard practice, but other advanced imaging modalities have shown variable results and hence more studies are awaited for further validation. Endoscopic eradication techniques, including both resection and ablation, have shown good but variable results for treating dysplastic lesions confined to the mucosa. Resection procedures to remove visible lesions followed by ablation of the dysplastic mucosa have shown the best results with higher eradication rates and lower recurrence rates. Surgical management is reserved for lesions with sub-mucosal invasion and lymph node spread with increased risk of metastasis.