S959 Prolonged Duration of Liquid Nitrogen Spray Cryotherapy Is Safe in Esophageal Cancer

Introduction: Liquid nitrogen spray cryotherapy (LNSC) is a thermal therapy aimed to achieve destruction of abnormal tissue in the gastrointestinal tract using freezing cold temperatures. It has been shown to effectively palliate malignancy induced dysphagia. Current practice suggests a 30-second spray per cycle duration; however, this approach is extrapolated from porcine models. The lack of proper studies has led to an inconsistent use. In the absence of dosimetry, its uptake into regular practice has been hampered by its concern for an increased liability. This study aims to evaluate the safety of prolonged spray cryotherapy in veterans with esophageal cancer. Methods: This single-center, institutional review board-approved, retrospective study was performed at a Veterans Affairs Medical Center. A single U.S. board-certified faculty member performed upper endoscopy with LNSC in veterans with malignancy-induced dysphagia. Data collection for each session of cryotherapy included the number of treatment sites, number of ablation cycles per site, duration of spray time, and complications. Spray time was defined as the total duration of application of LNSC on the targeted tissue. Treatment duration was determined by visual effect (i.e., hyperemic mucosa). Results: A total of 32 procedures were included. There was an average of 2.2 sites treated per session, 3.2 ablation cycles per site, and a spray time for each cycle of 101.4 seconds. There were no complications associated with these procedures which included intestinal perforation, intestinal hemorrhage requiring intervention, stricture development, or post-procedure discomfort not alleviated by topical therapy. Conclusion: Prolonged spray times using LNSC for esophageal cancer is proven to be safe and well tolerated. Further research is needed to discern dosimetry and ideal spray times.