2690 - Association of CT-Detected Proximal Airway Obstruction with Clinical Airway Events and Survival in Patients Receiving Palliative Thoracic Radiotherapy
Presenter(s)
H. Bacon1, A. M. Ladak2, M. McInnis3, C. McIntosh4, R. Daniel5, C. M. Yao6, and C. J. Tsai7; 1Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada, 2Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada, 3Joint Department of Medical Imaging, University of Toronto, Toronto, ON, Canada, 4Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada, 5Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Toronto, ON, Canada, 6Department of Otolaryngology - Head & Neck Surgery, Princess Margaret Cancer Centre/University of Toronto, Toronto, ON, Canada, 7Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
Purpose/Objective(s):
Malignant airway obstruction and hemorrhage carry high morbidity and mortality. Early identification of patients at risk before clinical decompensation may allow for early intervention.Materials/Methods:
This retrospective cohort study included consecutive adult patients who received palliative thoracic RT for primary or metastatic malignancy in the lung between January 2015 and June 2023 with chest computed tomography (CT) imaging =3 months prior. A segmentation algorithm identified proximal airways on CT, which were then classified as patent or obstructed by a subspecialty-trained thoracic radiologist. The primary outcome of the study was overall survival (OS). Secondary outcomes included airway obstruction severity graded by CTCAE v5, with grade = III events classified as catastrophic. The association of CT-detected obstruction with outcomes were assessed with univariable and multivariable Cox and logistic regression analyses.Results:
Among 280 patients meeting inclusion criteria, 62 had one obstructed airway on CT, 11 had two, 20 had three, and 13 had four or more. The presence of any proximal obstruction on CT was independently associated with worse OS (HR = 1.33; 95% CI: 1.00-1.77) and higher odds of clinical airway events (OR 2.61, 95% CI: 1.57-4.40). Increasing obstructed airways detected on imaging was associated with progressively higher odds of any clinical airway events (OR 1.50, 95% CI: 1.21-1.89) and catastrophic airway events (OR 1.34, 95% CI: 1.10-1.63). Compared with patients with primary lung cancer, those with head and neck primary tumors had significantly worse overall survival (HR = 1.99, 95% CI 1.31-3.03).Conclusion:
CT-detected proximal airway obstruction is a strong predictor of subsequent airway-related morbidity and mortality in patients undergoing palliative thoracic RT. Proactively quantifying airway obstruction on routine CT imaging may help identify high-risk patients earlier in their disease course and inform timely multidisciplinary management.
Table. Significant Associations from Cox Regression Models of Overall Survival in Patients Treated with Palliative Thoracic Radiotherapy. (Covariates without significant associations in any model included sex, age at RT, and cancer stage). Significant associations in bold text.
| Variables | Univariable Model HR (95% CI) | Univariable Model P-value | Multivariable Model HR (95% CI) | Multivariable Model P-value | |
| Proximal Airway CT Findings | Patent Proximal Airway (ref) | --- | --- | --- | --- |
| Proximal Airway Obstruction | 1.43 (1.09, 1.87) | 0.01 | 1.33 (1.00, 1.77) | 0.0497 | |
| Cancer Primary Site | Lung (ref) | --- | --- | --- | --- |
| Head and Neck | 1.99 (1.31, 3.03) | 0.001 | 1.96 (1.27, 3.03) | 0.002 | |
| Other | 0.78 (0.59, 1.04) | 0.09 | 0.83 (0.61, 1.12) | 0.21 | |
| Radiation Dose and Fractionation | 30 Gy / 10 (ref) | --- | --- | ||
| 20 Gy / 5 | 1.51 (1.03, 2.22) | 0.036 | 1.55 (1.04, 2.33) | 0.032 | |
| 8 Gy x 1 | 1.82 (1.01, 3.29) | 0.047 | 1.73 (0.94, 3.20) | 0.079 | |
| Other | 0.99 (0.57, 1.74) | 0.98 | 1.21 (0.67, 2.18) | 0.52 | |