Comparison of Clinical Features and Stent Placement Outcomes Between Airway Stenosis Caused by Primary Pulmonary Malignancies and That Caused by Primary Non-Pulmonary Malignancies
Malignant central airway obstruction (CAO) is a severe and often life-threatening condition that can result from various malignancies, including primary pulmonary malignancies (PPMs) and primary non-pulmonary malignancies (PNPMs). This study aimed to compare the clinical features and outcomes of stent placement in patients with airway stenosis caused by PPMs and PNPMs. The research was conducted over a 14-year period, from January 2004 to October 2017, at the Department of Respiratory Medicine, Beijing Tian Tan Hospital, Capital Medical University, involving 141 patients who underwent Micro-Tech stent placements.
The study divided the patients into two groups: those with PPMs (n=100) and those with PNPMs (n=41). The clinical features and outcomes of stent placement were analyzed using statistical methods, including the Chi-square test for categorical variables and independent- or paired-sample t-tests for continuous variables.
Clinical Features
The study found no significant differences in age, sex, treatment history, respiratory symptoms, and incidence of obstructive pneumonia between the two groups. However, multiple airway involvement (63.0% vs. 31.7%) and atelectasis (17.0% vs. 2.4%) were more common in the PPM group, while extraluminal obstruction (24.4% vs. 6.0%) was more common in the PNPM group.
Before stenting, the American Thoracic Society Dyspnea Index (ADI) and Karnofsky Performance Scale (KPS) scores showed no significant differences between the groups. After stenting, a satisfactory rate of symptom improvement was achieved in both groups (98.0% and 100.0% in the PPM and PNPM groups, respectively). The ADI and KPS scores were significantly improved in each group, with no significant differences between the groups. Complications after stenting were effectively managed using bronchoscopic procedures.
Stent Placement Outcomes
A total of 145 bare stents (117 straight and 28 Y-shaped) were successfully inserted in all patients without severe procedure-related complications. The proportion of Y-shaped stents used did not differ significantly between the two groups. After stent placement, immediate symptom improvement was achieved, with no significant difference in symptom improvement rate between the groups. The changes in ADI and KPS scores were significant within each group, indicating improved respiratory symptoms and performance status.
Complications After Stent Placement
Early complications, assessed within one week of stent placement, included mucosal necrosis, increased secretions, granulation, bleeding, migration, and glottic edema. These complications were generally mild and reversible, with no endoscopic procedure required for most cases.
Long-term follow-up (median, 86.5 days) was performed on 62 patients, revealing late complications such as tumor overgrowth, mucus retention, granulation formation, scar, fracture, epithelialization, and bleeding. Bronchoscopic interventions, including electrocautery snare, CO2 cryotherapy, high-frequency electric knife, argon plasma coagulation, and re-stenting, were performed to manage these complications. Tumor overgrowth was the most common reason for bronchoscopic intervention after stent placement.
Discussion
PPMs were the main cause of malignant CAO requiring stent placement, with squamous cell carcinoma, adenocarcinoma, and adenoid cystic carcinoma being the most common histological types. PNPMs causing malignant CAO often originated from mediastinal or extrathoracic organs, such as the esophagus and thyroid. The study highlighted the similarities in respiratory symptoms and patient characteristics between the two groups, emphasizing the challenges in diagnosing malignant CAO due to the lack of specificity in symptoms.
The study demonstrated that Micro-Tech stent placement is effective in improving symptoms and performance status in patients with malignant CAO caused by both PPMs and PNPMs. The stent-related complications were manageable with bronchoscopic interventions, underscoring the safety and efficacy of this palliative treatment approach.
Conclusion
In conclusion, this study provides valuable insights into the clinical features and outcomes of stent placement in patients with malignant airway stenosis caused by PPMs and PNPMs. The findings highlight the importance of tailored treatment strategies based on the underlying malignancy and the effectiveness of Micro-Tech stents in improving patient outcomes. The study also emphasizes the role of bronchoscopic interventions in managing stent-related complications, ensuring the safety and efficacy of the treatment.
doi.org/10.1097/CM9.0000000000000092
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