Lung cancer is often at an advanced stage when it is diagnosed, with low survival rates. Patients can develop endobronchial lesions that obstruct the major airways, causing symptoms such as dyspnoea, cough, haemoptysis and postobstructive pneumonia. Bronchial obstruction may lead to gradual asphyxiation.
The aim of treatment in patients with malignant endobronchial obstruction is mainly palliative. Current treatment options include a variety of endobronchial therapies such as bronchoscopic resection, brachytherapy, laser ablation, photodynamic therapy and stenting. Externalbeam radiotherapy and chemotherapy may also be used for palliative treatment.
General anaesthesia is usually used. A cryoprobe is inserted through a bronchoscope to reach the tumour; the probe diameter selected depends on the size and position of the tumour. After a period of freezing, the tumour is allowed to thaw until the probe separates from the tissue. The freeze and thaw cycle may be repeated two to three times in the same place. The probe is then moved to an adjacent area and the process is repeated until the whole tumour has been treated. Any resulting necrotic tumour material is then removed with forceps or using the cryoprobe. Further necrotic material may be expectorated during the following 24 to 48 hours. The procedure can be repeated if necessary.
Cryotherapy does not provide immediate relief of bronchial obstruction and is therefore not suitable for the emergency treatment of acute respiratory distress.