Cost-Effectiveness of Intensity Modulated Radiation Therapy vs. 3D Conformal Radiation Therapy in Stage III Non-Small Cell Lung Cancer

Abstract

External beam radiation therapy with concurrent chemotherapy is a standard of care therapeutic option for patients with stage III non-small cell lung cancer (NSCLC). A secondary analysis of the RTOG 0617 randomized clinical trial found that intensity modulated radiation therapy (IMRT) was associated with less ≥ grade 3 pneumonitis (7.9% vs. 3.5%; aOR 0.41, P = 0.046) compared to three-dimensional conformal radiation therapy (3D-CRT). However, IMRT is associated with increased costs. We therefore performed a cost-effective analysis of IMRT vs. 3DCRT for patients with stage III NSCLC.We developed a state-transition model to simulate the natural progression of stage III NSCLC. The model was calibrated to the RTOG 0617 trial with regard to progression-free survival, overall survival and rates of ≥ grade 3 pneumonitis. Costs and utilities were derived from the published literature. The outcomes measured were discounted quality-adjusted life years (QALYs) and costs from the US payer (Medicare) perspective. Incremental cost-effectiveness ratios (ICERs) were calculated, and we assumed a base case willingness-to-pay (WTP) of $100,000 per QALY. We performed sensitivity analyses for all key variables to assess the robustness of our base-case results. To quantify the impact of the uncertainty of model parameters on the outcomes, we performed a probabilistic sensitivity analysis over a wide range of thresholds. The Markov model was programmed and calibrated in R v.4.0.4 (R Foundation for Statistical Computing, Vienna, Austria).Model calibration showed excellent approximation the RTOG 0617 clinical data. IMRT net costs and QALYs were $171,792 and 1.60, respectively. 3DCRT net costs and QALYs were $163,048 and 1.54, respectively. Therefore, the ICER for IMRT was $120,917 per QALY. On deterministic sensitivity analyses, the model was sensitive to the cost of IMRT and was cost-effective when priced less than or equal to $6,811. On probabilistic sensitivity analysis, IMRT was cost-effective in 35%, 65% and 80% of simulations with WTP thresholds of $100,000, $150,000 and $200,000 per QALY.When taking into account model parameter uncertainty, IMRT is expected to be cost-effective in 35% of scenarios assuming a WTP threshold of $100,000. Above a WTP threshold of $125,000 per QALY IMRT is expected to be cost-effective in over 50% of scenarios. Thus, the cost-effectiveness of IMRT depends primarily on the WTP threshold.