Interventional bronchoscopic management of recalcitrant adenoid cystic carcinoma obstructing central airways

INTRODUCTION Adenoid cystic carcinoma (ACC) of the lung is a rare tumor with a propensity to cause central airway obstruction. Prolonged patient survival with high recurrence rates despite surgery, oncologic treatment or interventional bronchoscopic procedures (IBPs) poses long-term management challenges. With this study we aimed to review IBPs and their outcome in patients with ACC. METHODS We retrospectively reviewed the demographics, bronchoscopic findings, IBP treatment modalities and outcomes of patients with a diagnosis of ACC between January 2009 and December 2020. RESULTS There were 13 patients (9 male, 69.2%) with a mean age of 54.61±8.7 years. Trachea was the most involved site (10 cases, 76.9%) and percentage of obstruction was 77±13.9%. Bronchoscopy most commonly identified an endoluminal lesion (84.6%). There was a total of 77 procedures, including 44 rigid and 31 flexible bronchoscopies. Seven patients underwent a single procedure and 6 patients more than one procedure. Most common interventional bronchoscopic treatment modalities used were argon plasma coagulation (40.2%) and mechanical resection (38.9%). Airway stents were inserted in 4 (30.7%) patients. Airway patency was restored following first-line IBP in 93% of patients. The rate of early complications within the first 24 hours was 6.8%. Late complications were seen in 33.7% and were all stent related. No procedure related mortality was observed. CONCLUSIONS ACC affects central airways and most frequently the trachea. IBPs can be repeatedly used in the treatment of ACC because of their low early complication rates. Patients treated with airway stents should be closely followed up for late complications. ABBREVIATIONS ACC: adenoid cystic carcinoma, APC: argon plasma coagulation, CAO: central airway obstruction, COPD: chronic obstructive pulmonary disease, EBUS: endobronchial ultrasonographies, FB: flexible bronchoscopies, IBP: interventional bronchoscopic procedure, IP: interventional pulmonology, RB: rigid bronchoscopies. INTRODUCTION Adenoid cystic carcinomas (ACC) are rarely encountered tumors with a propensity for frequent recurrences originating from secretory glands of the tracheobronchial system that comprise 0.04–0.2% of all lung cancers. Previously classified as benign tumoral lesions, they are currently grouped under low-grade malignant tumors1. Although uncommonly encountered, they can lead to life threatening central airway obstruction (CAO). They progress insidiously, slowly growing longitudinally within the airways. Frequently patients are incorrectly diagnosed with and treated for asthma or chronic obstructive pulmonary disease (COPD). In patients who have already been diagnosed with ACC, worsening respiratory symptoms can be erroneously attributed to comorbidities or side effects of oncologic treatments. Consequently, both the initial diagnosis and the detection of disease progression can be delayed1,2. The treatment of choice is surgical resection. The longterm prognosis is favorable if surgery results in complete removal. Postoperative radiotherapy or/and chemotherapy is needed if residual tumor is found at the resection margin. Despite these treatments, rates of recurrence and local invasion remain high1,3. IBP is considered in patients who are not candidates for surgery or having tumor recurrence and when emergency treatment of airway obstruction is required. Securing the airway by IBP offers quick symptomatic palliation and can sometimes allow patients more time until surgery. Some studies have reported that IBP can have longAFFILIATION 1 Department of Pulmonology, Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, University of Health Sciences, Istanbul, Turkey CORRESPONDENCE TO Efsun G. Uğur Chousein. Department of Pulmonology, Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital, University of Health Sciences, Kazliçeşme Mh, Belgrat Kapi yolu Cad No:1, 34020 Zeytinburnu, Istanbul, Turkey. E-mail: efsungoncachousein@yahoo.com ORCID ID: https://orcid.org/0000-0002-8029-6627