To the Editors:
We read with interest the article by Vergnon et al. 1 in the European Respiratory Journal, about the place of cryotherapy, brachytherapy and photodynamic therapy in the therapeutic bronchoscopy of lung cancers. The article describes indications and limitations of cryotherapy. In the opinion of Vergnon et al. 1, the effect of cryotherapy is delayed and is, therefore, not useful for the immediate debulking of an obstructive endoluminal bronchial tumour. For these cases, Vergnon et al. 1 advise coring of the tumour with the rigid bronchoscope and subsequent laser therapy or electrocautery. The indication for cryotherapy in this setting is seen as a treatment option for any remaining infiltrative parts of the tumour into the bronchial wall, but not as a treatment option of first choice to remove the main part of an exophytic tumour.
In our clinic, we have positive experience in a large number of patients with the application of cryotherapy for the immediate treatment of acute dyspnoea in patients with obstructive malignant bronchial tumours. We use the cryorecanalisation technique with the rigid bronchoscope under general anaesthesia, as well as with a flexible technique during local anaesthesia and sedation. The commercially available flexible cryoprobe (ERBE, Tübingen, Germany) we use is 780 mm in length and 2.3 mm in diameter. The probe's tip is cooled to -89.5°C by sudden gas decompression (nitrous oxide) in the probe's head. The cryoprobe is a closed system, which can be re-sterilised and re-used. In many cases, we use the cryorecanalisation method in combination with argon plasma coagulation for a more immediate treatment of diffuse tumour bleeding after coring with the rigid bronchoscope.
We apply the following technique: 1) the flexible cryoprobe is introduced via a flexible bronchoscope in combination with an Ikeda tubus or a rigid bronchoscope; 2) the tip of the cryoprobe is pushed into the protruding exophytic tumour mass and freezing is started for ≤5 s with a footpad; 3) the cryoprobe, including the flexible bronchoscope, is abruptly mechanically removed, a tumour mass of 3–5 mm is frozen at the tip of the cryoprobe and can easily be extracted; 4) rapid thawing is induced in a water bath for ≤5 s; and 5) the procedure is repeated until the tumour mass has been extracted and the target bronchus is re-opened. If necessary, subsequent stent implantation is performed in the same session without any problems. With this technique, we have seen no severe bleedings if coagulation parameters were within the normal range. Overall, we have a very low complication rate. Severe bleeding during re-canalisation with the cryoprobe is very rare, we have never seen perforations, and the primary success rate of re-canalisation is very high (>90%), even in long-distance stenoses, and in our experience comparable to that of laser beam or electrocautery. The feasibility of this method for the immediate management of acute airway obstruction has already been published 2. In contrast to the cryotherapy technique described by Vergnon et al. 1, which requires a second bronchoscopy after 8–10 days for the removal of necrotic tissue, a second-look bronchoscopy is not mandatory with our technique.
In addition, the specimens obtained by cryorecanalisation for diagnostic purposes are much larger and of excellent tissue quality, without squeezing artefacts, compared with specimens extracted using forceps. In a study with 60 patients, comparing specimen quality in forceps biopsy and cryobiopsy, we found the cryobiopsy technique to have a superior diagnostic quality 3.
In summary, the use of the flexible cryoprobe for mechanical removal of obstructive exophytic bronchial tumours is a good alternative to laser therapy or electrocautery in planned bronchoscopic interventions as well as in patients with acute dyspnoea and tumorous bronchial obstruction. Cryorecanalisation is safe, cheap and readily applicable with an immediate success and relief of symptoms.
- © ERS Journals Ltd