Population-Based Estimates of Survival Benefit Associated with Combined Modality Therapy in Elderly Patients with Locally Advanced Non-small Cell Lung Cancer

Purpose: Combined modality therapy (CMT; radiation and chemotherapy) is indicated for fit, elderly patients with inoperable, locally advanced non-small cell lung cancer. We used population level data to examine effects of CMT on survival. Methods: Medicare patients who are 66 years or older with locally advanced non-small cell lung cancer (stages IIIA and IIIB without pleural effusion) from 1997 to 2002 were identified in Surveillance Epidemiology and End Results-Medicare. Detailed insurance claims were used to characterize treatment modality (none, chemotherapy only, radiotherapy only [XRT-ONLY], or CMT). CMT was further categorized as sequential (CMT-SEQ), or concurrent chemoradiation alone (CMT-ONLY), with induction (CMT-IND), or with consolidation chemotherapy (CMT-CON). Nonparametric models estimated survival effects of treatment regimens, controlling for patient characteristics, including claims-based indicators of performance status. Propensity score analysis adjusted for treatment selection. Results: Of the 6325 patients, 66% received therapy, with 41% (N = 1745) receiving XRT-ONLY and 45% (N = 1909) receiving CMT (12.5% CMT-SEQ, 35.3% CMT-ONLY, 11.3% CMT-IND, and 20.3% with CMT-CON). CMT had a survival benefit relative to XRT-ONLY (hazard ratio: 0.782, 95% confidence interval: 0.750-0.816; additional 4.4 months median survival; adjusted 10.7% increase in 1-year survival). Relative to CMT-SEQ, concurrent CMT-ONLY was associated with an increased mortality risk, whereas CMT-IND regimens provided a survival benefit (hazard ratio: 0.731, 95% confidence interval: 0.600-0.891; additional 3.8 months; and adjusted 14.4% increase in 1-year survival). Conclusion: Survival benefits associated with CMT in clinical trials can extend to the elderly in routine care settings. CMT-ONLY is associated with the greatest mortality risk, suggesting that more gradual strategies (CMT-IND) may be more appropriate for the elderly population.