Content area
Full Text
Abstract
Cryotherapy is an evolving therapeutic and diagnostic tool used during bronchoscopy. Through rapid freeze-thaw cycles, cryotherapy causes cell death and tissue necrosis or tissue adherence that can be used via the flexible or rigid bronchoscope. This extreme cold can be used through the working channel of the bronchoscope via a specialized cryoprobe or directly with the use of spray cryotherapy. These properties allow for multiple bronchoscopic techniques, each with its own equipment and procedural, safety, and efficacy considerations. Bronchoscopic cryotherapy can be used in a variety of clinical scenarios, including the treatment of malignant and benign central airway obstruction and low-grade airway malignancy, foreign body removal or cryoextraction, endobronchial biopsy, and transbronchial biopsy. The bulk of the experience with bronchoscopic cryotherapy consists of uncontrolled case series of malignant central airway obstruction. There are also controlled data supporting the use of cryoadhesion for endobronchial biopsies, albeit with an increased risk of controllable bleeding. The use of cryoadhesion for transbronchial biopsies is an active area of investigation with limited controlled data. In addition, there are promising future directions using bronchoscopic cryotherapy, including chemosensitizing malignancy with cryotherapy and capitalizing on the synergy between cryotherapy and radiation.
Keywords: airway obstruction; bronchial neoplasms; bronchoscopy
Cryotherapy is the use of extreme cold to destroy tissue using rapid freeze-thaw cycles. It was first used on an endobronchial tumor in 1968 by Gage, who used a rigid applicator known as a cryoprobe (1). The use of cryotherapy became more widespread with the advent of the flexible cryoprobe in 1994 (2). More recently, endoscopic spray cryotherapy has been used in the central airways during bronchoscopy. Furthermore, cryoadhesion has been used to expand the role of probe cryotherapy to include cryorecanalization and cryobiopsy. With the variety of techniques available, cryotherapy is now being used in several clinical settings, including the treatment of benign and malignant central airway obstruction, transbronchial biopsy, endobronchial biopsy, foreign body removal, and the treatment of low-grade airway malignancy.
International guidelines in interventional pulmonology were conceived well before bronchoscopic cryotherapy included the more recent techniques of cryoadhesion and spray cryotherapy (SCT). European Respiratory Society/American Thoracic Society guidelines from 2002 endorsed cryotherapy for palliation of inoperable malignancy causing central airway obstruction and for foreign body and clot removal. These guidelines also...