Estimated Cost-Effectiveness of Low-Dose CT Screening for Lung Cancer
The National Lung Screening Trial (NLST) showed that low-dose computed tomography (CT) screening reduced lung cancer mortality compared with chest radiography. In a cost-effectiveness analysis in NLST reported in The New England Journal of Medicine, Black et al found that low-dose CT screening was associated with incremental cost-effectiveness ratios of $52,000 per life-year gained and $81,000 per quality-adjusted life-year gained compared with no screening. However, cost-effectiveness estimates varied widely in subgroup and sensitivity analyses.
Estimates of life-years were derived from the number of observed deaths during the trial and projected survival of persons alive at the end of the trial. Quality adjustments were based on data from a subgroup who were selected to complete quality of life surveys. Costs were based on utilization rates and Medicare reimbursements (for 2009).
Estimated Incremental Cost-Effectiveness Ratios
Compared with no screening, low-dose CT screening cost an additional $1,631 per person (95% confidence interval [CI] = $1,557–$1,709) and provided an additional 0.0316 life-year per person (95% CI = 0.0154-0.0478 life-year) and 0.0201 quality-adjusted life-years per person (95% CI = 0.0088–0.0314 quality-adjusted life-year). The corresponding incremental cost-effectiveness ratios were $52,000 per life-year gained (95% CI = $34,000–$106,000) and $81,000 per quality-adjusted life-year gained (95% CI =$52,000–$186,000).
Variation by Subgroup and in Sensitivity Analyses
Incremental cost-effectiveness ratios varied widely in subgroups. Estimated costs per quality-adjusted life-year were: $147,000 for men and $46,000 for women; $152,000, $48,000, $54,000, and $117,000 for participants aged 55 to 59, 60 to 64, 65 to 69, and 70 to 74 years at trial entry; $615,000 for former smokers and $43,000 for current smokers; and $169,000, $123,000, $269,000, $32,000, and $52,000 for lowest- to highest-risk quintiles.
Similarly, incremental cost-effectiveness ratios varied widely in sensitivity analyses. Incremental cost-effectiveness ratios were reduced to $54,000 when reduction in mortality from causes other than lung cancer were included and to $55,000 when half (rather than all) the excess lung cancers in the CT group were attributed to overdiagnosis. Incremental cost-effectiveness ratios approached or exceeded $100,000 when analyses included future health-care costs; used higher estimates of costs for screening, follow-up, and surgery vs those used in the primary analysis; used pessimistic survival expectations for stage IA non–small cell lung cancer; and included small reductions in quality of life related to positive screening results and a diagnosis of stage IA lung cancer. The incremental cost-effectiveness ratio also rose slightly when analysis included estimated deaths from radiation-induced lung cancer.
The investigators concluded: “We estimated that screening for lung cancer with low-dose CT would cost $81,000 per quality-adjusted life-year gained, but we also determined that modest changes in our assumptions would greatly alter this figure. The determination of whether screening outside the trial will be cost-effective will depend on how screening is implemented.”
William C. Black, MD, of the Geisel School of Medicine at Dartmouth, Dartmouth–Hitchcock Medical Center, is the corresponding author for The New England Journal of Medicine article.
The study was funded by the National Cancer Institute. The study authors reported no potential conflicts of interest.
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