Efficacy and Survival after Palliative Radiotherapy for Malignant Pulmonary Obstruction.

Introduction: The purpose of this study was to determine the efficacy of palliative radiotherapy (PRT) for patients with pulmonary obstruction from advanced malignancy and identify factors associated with lung re-expansion and survival. Materials and Methods: We reviewed all patients treated with PRT for malignant pulmonary obstruction (n = 108) at our institution between 2010 and 2018. Radiographic evidence of lung re-expansion was determined through review of follow-up CT or chest X-ray. Cumulative incidence of re-expansion and overall survival (OS) were estimated using competing risk methodology. Clinical characteristics were evaluated for association with re-expansion, OS, and early mortality. Treatment time to remaining life ratio (TT:RL) was evaluated as a novel metric for palliative treatment. Results: Eighty-one percent of patients had collapse of an entire lung lobe, 46% had Eastern Cooperative Oncology Group (ECOG) performance status 3-4, and 64% were inpatient at consultation. Eighty-four patients had follow-up imaging available, and 25 (23%) of all patients had lung re-expansion at median time of 35 days. Rates of death without re-expansion were 38% and 65% at 30 and 90 days, respectively. Median OS was 56 days. Death within 30 days of PRT occurred in 38%. Inpatients and larger tumors trended toward lower rates of re-expansion. Notable factors associated with OS were re-expansion, nonlung histology, tumor size, and performance status. Median TT:RL was 0.11 and significantly higher for subgroups: ECOG 3-4 (0.19), inpatients (0.16), patients with larger tumors (0.14), those unfit for systemic therapy (0.17), and with 10-fraction PRT (0.14). Conclusion: One-fourth of patients experienced re-expansion after PRT for malignant pulmonary obstruction. Survival is poor and a significant proportion of remaining life may be spent on treatment. Careful consideration of these clinical factors is recommended when considering PRT fractionation.