Tuesday, December 2, 2014

High Dose Rate Brachytherapy for Nonmalignant Airway Obstruction

Study objectives: High dose rate (HDR) endobronchial brachytherapy is widely used as a palliative treatment for symptomatic airway obstruction by primary or secondary malignant tumors. We report on a successful use of HDR brachytherapy in patients with nonmalignant airway obstruction. Design: Case series. Patients: Six patients received HDR brachytherapy for airway obstruction caused by granulation tissue around a metal stent placed for restoration of the airway patency for nonmalignant causes.
Nonmalignant Airway Obstruction

In four patients, brachytherapy was performed following recurrent occlusion of the airway by granulation tissue formation; in two patients, it was done as a prophylactic procedure. Intervention: HDR brachytherapy catheters were passed through the metal stents under direct fluoroscopic guidance. Simulation and computerized treatment planning were done, and a single dose of 10 Gy was administered using a brachytherapy remote afterloader with source. The dose was prescribed to a distance of 1 cm from the center of the source, with a margin of 1 cm from the proximal and distal ends of the stent. Results: 

At a median follow-up of 15 months, moderate granulation tissue formation was observed in only one patient; in four others, it was categorized as minimal, 5 to 30 months from the procedure. Restoration of the lumen was complete in four patients, near complete in one patient, and partial in one patient. In one patient, previously treated by external radiotherapy, local tissue necrosis was evident. Conclusion: HDR brachytherapy can be used safely for nonmalignant airway obstruction. Further studies including more patients and longer follow-up are needed.  

High dose rate (HDR) brachytherapy is a radiotherapeutic technique wherein high-dose radiation is delivered from a source located inside the patient’s body, using a rapid flux of ionizing particles. This enables the application of very accurately localized treatment, and thereby a higher therapeutic index, than that documented for the more frequently used external radiotherapy. HDR endobronchial brachytherapy is widely used as a palliative measure to overcome mechanical obstruction of major airways caused by either primary or secondary malignant tumors. It allows the delivery of a high dose of radiation over a short period of time to the obstructed area, and at the same time reducing the risk of undesired side effects to adjacent structures.

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