The US national lung cancer screening programme

History of lung cancer screening research in the US

The US has a long history of researching the utility of lung cancer screening. Early studies explored the use of chest X-ray (CXR) for screening, and in the 1990’s investigations began on the use of low-dose computed tomography (LDCT).^1-3

The US National Lung Screening Trial (NLST) was a landmark randomised controlled trial with 55,000 participants that compared LDCT screening with CXR. In 2011, the results from the NLST reported that LDCT screening reduced lung cancer mortality in high-risk individuals by 20%.⁴

Results from this study led several organisations, including the US Preventive Service Task Force (USPSTF) and the National Comprehensive Cancer Network, to formally recommend a nationally organised LDCT lung cancer screening programme.^{5 6}

The national programme was implemented for a high-risk population in 2015.
 

Overview of the US national screening programme

There are now over 4,000 sites in the US that offer annual LDCT screening as part of the national programme. LDCT screening is also covered by the federal health insurance programme, the Centers for Medicare and Medicaid Services (CMS).⁷

Current guidelines used to determine who is eligible for screening were updated by the USPSTF in 2021. The CMS also updated its guidelines in 2022.

Broadly speaking, both sets of guidelines currently recommend screening for people aged 50 years and over who currently smoke, used to smoke (equivalent to 20 pack-years), or have quit smoking within the past 15 years.^{5 8}

However, there are some differences in which criteria qualify for reimbursement by health insurance providers. Additionally, there is variation around which guidelines are applied to community programmes.⁹
 

Areas of ongoing implementation research

Despite this being one of the first national LDCT screening programmes, participation rates remain an important challenge. Even prior to the COVID-19 pandemic, lung cancer screening was underutilised, with only 5–6% of eligible adults receiving screening in 2018.¹⁰

Reasons behind low participation are complex, but include difficulties around insurance coverage and low awareness of the programme among those at the highest risk of lung cancer, especially minority ethnic groups.¹¹

Many sites performing screening also report logistical and operational challenges, including barriers to data sharing, which can have an impact on monitoring the quality of programmes.^{7 12} This can be partly due to differences in how individual screening programmes are structured.

For example, individuals may be recruited for screening by a range of healthcare professionals outside of primary care, including specialist clinics where there is a high prevalence of smoking-related diseases (e.g. cardiology, chronic obstructive pulmonary disease).

Lung cancer screening can also be requested privately (opportunistically), and some earlier studies estimated that around 20% of primary care physicians in the US were still using CXR.^{13 14} For this reason, one approach to better support clinical practices as they transition to become a centre for organised screening is accreditation by medical professional organisations, which helps ensure the quality of lung cancer screening.¹⁵

Given these challenges, there is still a wealth of ongoing research in the US to try and optimise the implementation of screening within the national programme.

The Lung Cancer Policy Network is publishing brief case studies of countries that have implemented LDCT screening; you can read other examples here.

We will also continue to build the extensive implementation research in the US into the second edition of the map.

View the interactive map