Bronchoscopic Debulking Treatment for Feline Tracheobronchial Carcinoma
Kate Boatright, VMD
What is the role of minimally invasive bronchoscopy in the treatment of tracheal tumors in cats?
Tracheal tumors in cats present a therapeutic challenge due to lack of an established standard of care. These tumors, while rare, are most commonly lymphomas, squamous cell carcinomas, or adenocarcinomas.
In humans, tracheal masses are typically treated with surgical resection and anastomosis. Interventional bronchoscopy is used as a minimally invasive option and in cases of nonresectable tumors. Previously reported therapies in veterinary medicine include surgical resection, chemotherapeutic intervention, radiation therapy, and bronchoscopic debulking.
A recently published case report from France described the successful treatment of feline tracheobronchial carcinoma using bronchoscopic debulking and adjuvant chemotherapy.
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A 10-year-old female spayed Russian blue cat presented with respiratory difficulty that was refractory to empiric medical management with theophylline, terbutaline, dexamethasone, and cyclosporine. The patient was in poor body condition (body condition score 3/9), had increased respiratory effort, and had decreased bronchovesicular sounds and wheezes on auscultation. Thoracic radiographs showed bilateral hyperinflation of the lungs and disruption of the tracheobronchial bifurcation consistent with a central airway obstruction.
Bronchoscopy revealed a multilobulated mass obstructing 90% of the airway. Due to its location at the carina, the mass was not amenable to surgical resection. A 3.3-mm urinary catheter was passed through the mass to allow oxygen delivery, and a surgical vacuum was used to aspirate portions of the mass through the lateral hole of the catheter. The procedure was successful due to the friable nature of the mass and resulted in 95% airway clearance. The patient was discharged on a tapering dose of prednisone the day after the procedure.
Histopathology of the mass was consistent with a tracheobronchial adenocarcinoma, and adjuvant chemotherapy with doxorubicin was initiated. The patient remained asymptomatic for 1 year following the initial debulking procedure.
Two additional bronchoscopic debulking procedures were performed as clinical signs returned. The second procedure, performed 1 year after the first, resulted in partial airway restoration (about 60%) and 3 months of clinical improvement. A third procedure also yielded partial clearance of the airway (about 50%) but only 1 month of clinical improvement. At this time, the owners elected euthanasia. The overall survival time after the first bronchoscopic procedure was 16 months (480 days).
This is the first veterinary case report of minimally invasive bronchoscopic treatment resulting in long-term survival. Previously reported survival times in 1 dog and 3 cats with airway tumors treated with bronchoscopy ranged from 1 to 9 months. Bronchoscopic aspiration of airway masses offers a palliative option that is “relatively simple, non-invasive, safe, and affordable.” The authors predict that this type of treatment will become more widely used in veterinary medicine in the future.
Dr. Boatright, a 2013 graduate of the University of Pennsylvania, is an associate veterinarian in western Pennsylvania. She is actively involved in her state and local veterinary medical associations and is a former national officer of the Veterinary Business Management Association.