Bronchoscopic Application of Mitomycin-C as Adjuvant Treatment for Benign Airway Stenosis

Abstract

The management of benign stenosis of the central airways continues to be challenging. Acquired benign airway stenosis can result from a variety of injuries to the airway wall: ischemia related to endotracheal intubation, surgical procedures such as tracheotomy or airway resection, chemical or thermal injury, direct mechanical trauma after bacterial or mycobacterial infections, from inflammatory diseases affecting the airways such as Wegener granulomatosis or sarcoidosis, after radiotherapy, stent-stimulated granulation tissue, and idiopathic when the cause can not be identified. After any of the afore-mentioned damages to the mucosa, the following inflammatory process activates fibroblasts to participate in wound healing. Fibroblasts synthesize several factors, such as transforming growth factor b1 and basic fibroblast growth factor, that stimulate the production of extracellular matrix components, leading to scar formation and contraction at the stenosis site. The same mechanism takes place in restenosis. Current treatment includes surgical resection as the first option. However, when surgery is unsuitable because of the patient’s clinical or respiratory conditions or airway issues, endoscopic approaches need to be considered. Airway patency can be reestablished by means of mechanical dilation with the bevel of the rigid bronchoscope, balloon inflation, laser ablation, electrocautery or argon plasma coagulator, stent insertion, or usually, a combination of any of the above. However, a high rate of restenosis ranging from 40% to 70% has been reported after the endoscopic treatment of tracheal stenosis, urging a need for therapies aimed to obtain better results. Treatments studied to reduce relapses include steroids, 5-fluorouracil, halofuginone, tamoxifen, and mitomycin-C (MMC). Mitomycin is an antibiotic that was isolated from the bacteria Streptomyces caespitosus in 1956. Its C-form is an alkylating agent that inhibits deoxyribonucleic acid synthesis. It was first used as an anticancer drug. It has also been used in ophthalmologic procedures to reduce corneal scarring and recently in the treatment of benign airway stenosis.