Risk-Targeted Lung Cancer Screening Shows Modest Benefits

Although risk targeting may improve screening efficiency in terms of early lung cancer mortality per person screened, the gains in efficiency are modest in terms of life-years, quality-adjusted life-years (QALYs), and cost-effectiveness, according to a study recently published in Annals of Internal Medicine, entitled “Risk-Targeted Lung Cancer Screening: A Cost-Effectiveness Analysis."

The National Lung Screening Trial (NLST) demonstrated a 20% reduction in lung cancer deaths among persons screened with low-dose computed tomography (LDCT) versus chest radiography. This study reports that most subsequent guidelines, including those from the US Preventive Services Task Force, have largely adopted the NLST eligibility criteria when recommending patients to receive lung cancer screening.

Researchers in this study applied a multistate model to calculate the predicted lifetime benefits and costs of screening with LDCT versus chest radiography for each NLST participant. These estimates were then used to determine the value of applying an individualized risk-targeted approach to selected participants for screening compared with the broader NLST inclusion criteria.

Results demonstrated that participants at the highest baseline risk of death from lung cancer achieved the greatest benefit in terms of LDCT-prevented lung cancer deaths in the first 7 years after screening began: 80% of lives can be saved by targeting the highest-risk 60%. However, the study also found that the higher-risk participants were older, had greater smoking exposure, and were more likely to have a preexisting diagnosis of chronic obstructive pulmonary disease. The participants who were at a greater risk for lung cancer also generated higher screening costs because they had more invasive testing after a positive result.

Screening with LDCT increased lifetime costs by $1089 compared with chest radiography screening, yielding incremental cost-effectiveness ratio for LDCT of $37,000 per life-year gained or $60,000 per QALY gained in the overall NLST cohort.

In most of the scenarios the study ran, the cost-effectiveness of NLST-based screening and individualized (risk-based) screening strategies yielded the same results: screen everyone with either LDCT or chest radiography, depending on the willingness-to-pay threshold. Even in sensitivity analyses in which LDCT screening was cost-effective for some high-risk participants and not for low-risk participants, making individualized decisions did not yield substantial benefits because the tradeoffs involved in exchanging costs and QALYs were nearly equivalent.

Researchers confirmed previous work that showed that more early lung cancer deaths can be avoided per patient screened by applying risk targeting that is more specific than the overall inclusion criteria of the NLST. However, higher-risk patients are costlier to screen and have a lower life expectancy if they survive lung cancer. This led researchers to conclude that applying a risk model such as the one in this study is unlikely to lead to substantial improvement in the cost-effectiveness of LDCT screening in terms of QALYs gained, per unit cost.