The role of adjuvant chemotherapy in stage IB non-small cell lung cancer: A decision, effectiveness, and cost-effectiveness analysis.

Abstract

8526 Background: Despite complete surgical resection (SR), half of stage I non-small cell lung cancer (NSCLC) patients die from systemic relapse. An independent risk factor for systemic progression is pathologic stage IB subtype (T2aN0M0, AJCC 7). The role of adjuvant chemotherapy (AC) in stage IB NSCLC is controversial. We studied the effectiveness and cost-effectiveness of AC after SR in stage IB NSCLC. Methods: Propensity score matching was performed on the National Cancer Database (2004-2011). The Kaplan-Meier method generated conditional probabilistic incremental 1- to 5-year survival after SR stratified by receipt of AC. Medicare allowable charges for SR, AC, and their respective complications were used. Decision analysis modeling and microsimulation were performed to account for proportions of chemotherapeutic agents administered in real-world settings. The incremental cost-effectiveness ratio (ICER) was calculated over a 5-year horizon. Probabilistic and two-way sensitivity analyses were performed. Results: 3662 of 18709 patient (19.6%) who met inclusion criteria received AC for SR stage IB NSCLC, with usage ranging from 15-27% annually. After propensity score matching, an overall survival benefit of AC was conferred over SR alone (at 5 years: 68.9% vs 60.4%, p < 0.001). The incremental cost of AC over SR alone was $11,541. The incremental effectiveness of AC was 0.28 life-years, with an ICER of $41,218. In two-way sensitivity analysis, AC plus SR dominated for the entire range of cost and survival estimates. In probabilistic sensitivity analysis, AC plus SR dominated the model above a willing-to-pay threshold of $16,000. AC costs could nearly double and the ICER remained under conventional thresholds. However, only 3 of the 4 common AC regimens were cost effective. Conclusions: In stage IB NSCLC, surgery is insufficient to render a cure. The addition of AC to SR extends life-expectancy and is cost-effective compared to SR alone. These conclusions are valid over a range of clinically meaningful variations in cost and treatment outcomes, though a cost-conscious approach is needed when selecting an AC regimen. This represents a novel change in the treatment of stage IB NSCLC.