Technique and emerging role of cryotherapy

Cryotherapy is a novel endoscopic method of ablating abnormal gastrointestinal (GI) mucosa with cryogens originating from either liquid nitrogen or carbon dioxide gas. The ablation is performed by passing a catheter through the accessory channel of an endoscope and the cryogen is sprayed onto the target tissue in a noncontact manner. Cell death is induced by producing extracellular ice. Recently, several reports have been published on the efficacy of cryotherapy for clinical use in the GI tract. In Barrett's esophagus, reports describe that cryotherapy was effective to eradicate or downgrade Barrett's associated dysplasia. Cryotherapy has also been reported to be useful for palliation of squamous cell carcinoma. Chronic recurrent bleeding from watermelon stomach (gastric antral vascular ectasia [GAVE]) and radiation-induced proctitis have also been found responsive to cryotherapy. Although based on results with relatively small numbers of patients and short follow-up periods, cryotherapy has been demonstrated to be safe and effective. This is a promising technology that will require multicenter controlled trials to better define its role as an effective and alternative form of tissue ablation.