Age Is Just a Number? A Retrospective Review of Cause of Death in Patients 85 Years and Over Receiving Lung Stereotactic Ablative Radiotherapy.

Introduction: Patients aged > 85 years are under-represented in research that has established stereotactic body radiotherapy (SBRT) as the standard of care in early stage non-small cell lung cancer (NSCLC) not suitable for or refusing surgery. With an ageing population in Australia, it is important to assess SBRT and cause of death (COD) in elderly patients receiving curative intent lung SBRT.

Methods: This is a multi-centre retrospective review of eligible patients treated across Australia from 2016 to 2022 with curative intent lung SBRT for early stage primary NSCLC, and aged 85 years or over. The primary outcomes were estimated 2-year overall survival (OS) and COD. Secondary outcomes include cancer-specific survival (CSS), progression-free survival (PFS) and local PFS following SBRT. Univariate Cox regression was used to determine factors associated with survival outcomes or progression.

Results: In the study, 103 patients were identified, treated with 109 courses of SBRT. Median age was 87.6 years (range 85-97.1) with 52.4% male (n = 54). Median follow-up was 19.6 months (range 0.2-55.6). The estimated 2-year survival was 78.7% (95% CI 67.8-86.3). Of the 27.2% (n = 28) of patients deceased, COD was established in 89.3% (n = 25) of cases. In addition, 39.2% (n = 11) of deaths were related to lung cancer. Univariate analysis demonstrated that survival varied significantly with poorer performance status.

Conclusion: This study increases knowledge of efficacy of lung SBRT in the very elderly, suggests similar outcomes to the general patient population and supports the use of lung SBRT in those aged 85 years or over. Prospective data including outcomes, comorbidities, pulmonary function and toxicity are required to help inform clinicians and patients about decisions regarding treatment.