Background:Tracheobronchial mucoepidermoid carcinoma (MEC) is a rare airway tumor in adults for which surgery is considered a first-line treatment.However,some patients already lost the best opportunity of a surgical intervention when diagnoses are confirmed,and surgery causes considerable trauma resulting in partial loss of pulmonary function.Moreover,the tumor is resistant to radiotherapy and chemotherapy.These factors make the treatment of tracheobronchial MEC challenging.This study aimed to evaluate the safety and efficacy of interventional bronchoscopic therapy in adult patients with tracheobronchial MEC.Methods:We retrospectively analyzed the clinical manifestations,bronchoscopic interventions,complications,and outcomes of 11 adult patients with tracheobronchial MEC.Paired t-test was used to analyze the parameters of the American Thoracic Society Dyspnea Index and the Kofsky Score before and after the first interventional bronchoscopic therapy.Results:All tumors occurred in the main bronchus and were easily visualized by bronchoscopy.After interventional bronchoscopic therapy,the symptoms of all patients showed significant improvement.The American Thoracic Society Dyspnea Index decreased from 1.91 ± 1.22 to 0.27 ± 0.47 (t =6.708,P＜ 0.001) and the Kofsky Score increased from 78.18 ± 16.62 to 95.46 ± 8.20 (t =-5.190,P ＜ 0.001).Bronchoscopic intervention did not result in serious complications or mortality.During the follow-up period between 3 and 96 months after the first therapy,the following results were noted:(1) among the eight patients with low-grade tracheobronchial MEC,only one patient had a relapse and agreed to surgical treatment;(2) among the three patients with high-grade tracheobronchial MEC,one patient required repeated bronchoscopic interventions,one patient died of pulmonary infection,and one patient died of systemic failure owing to tumor metastasis.Conclusions:Interventional bronchoscopic therapy,as an altative treatment,shows promise in some adult patients with low-grade tracheobronchial MEC confined to the bronchus.However,for adult patients with high-grade tracheobronchial MEC,early diagnosis and surgical treatment are still strongly recommended.