Laser ablation therapies for Barrett's esophagus

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.

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

Role of photodynamic therapy in unresectable esophageal and lung cancer

The incidence of esophageal cancer has increased dramatically in the Western population in the last two decades. Many of these patients tend to present late in the disease course with symptoms of dysphagia and malnutrition. Thus a majority of patients at presentation may require palliation of their symptoms. Lung cancer is the most common cause of cancer related mortality in the United States. Similar to esophageal cancer, many patients present in advanced stages where surgical resection for cure may not be an option. Endobronchial obstruction from both primary and metastatic neoplasm causes significant morbidity. The modalities, which are currently available for palliation of symptoms include surgery, photodynamic therapy, dilation, external beam radiation, stents, Nd:YAG laser therapy, and brachytherapy. Each of these modalities has their specific advantages and drawbacks. In this article, we discuss the role of photodynamic therapy in the palliation of esophageal and lung cancer.