2814 - Clinical Outcomes of Inpatient Palliative Radiotherapy for Malignant Airway Obstruction: A Retrospective Cohort Study

Purpose/Objective(s): Malignant airway obstruction (MAO) is a common indication for urgent palliative radiotherapy (RT) in hospitalized cancer patients. Data are limited on short-term survival and symptom response rates after RT in this setting. We aimed to characterize survival outcomes to improve prognostication and guide treatment decision-making, identifying patients most likely to benefit from inpatient radiotherapy.

Materials/Methods: We performed a retrospective cohort study of adult inpatients at our institution who received palliative RT between January 2016 and December 2024 for MAO. Primary endpoint was 30-day survival. Secondary endpoints included overall survival, survival after hospital discharge, symptom improvement, and unplanned events during treatment. Collected variables included demographics, Karnofsky performance status (KPS), metastatic disease status, hospital location (ICU vs non-ICU), intubation status, and baseline laboratory values (albumin and hemoglobin). Univariable and multivariable logistic regression were used to evaluate predictors of survival beyond 30 days.

Results: A total of 101 inpatients received palliative RT for MAO; 70% had a primary lung malignancy, and 30% of patients had nonmetastatic disease. The most common fractionation regimens were 8 Gy in 1 fx (44%), 20 Gy in 5 fx (30%), and 10 Gy in 1 fx (13%). CT simulation was performed in 81% of cases, and 23% of treatments were initiated on a weekend.

At the time of consultation, 44% of patients were admitted to the ICU and 21% were intubated; among intubated patients, 47.8% were successfully extubated after radiation. Overall, 52% of patients experienced improvement in respiratory status following RT. Seventeen percent of patients died during the index hospitalization.

Median overall survival was 43 days, with a 30-day mortality rate of 43%. Patients in the ICU at consultation had significantly worse survival compared to non-ICU patients (median 18 vs 73 days, p=0.007). On univariable analysis, higher KPS, higher baseline albumin and hemoglobin, absence of metastatic disease, and non-ICU/non-intubated status were associated with survival beyond 30 days. On multivariable analysis, absence of metastatic disease remained independently associated with survival >30 days (OR 4.95, 95% CI 1.5–16.1, p=0.008). Unplanned events during RT occurred in 5% of patients (anxiety or hypoxia).

Conclusion: Among hospitalized patients treated with RT for MAO, short-term mortality was high, with nearly half dying within 30 days. ICU admission was associated with a median survival of less than three weeks, and metastatic disease independently predicted early mortality.

These findings underscore the need for improved prognostic stratification to better align inpatient palliative RT with expected clinical benefit.