Looking for lung cancer

The US Department of Health is now recommending the cohort of Americans eligible for yearly lung cancer screening be widened to include people who are younger and who have less significant smoking histories. 

The new recommendations reflect the latest data showing the impact of screening via low-dose computed tomography (LDCT) on death rates from the disease, marking a change that may help to shape global practice.

The department’s Preventive Services Task Force now recommends that all adults aged 50 to 80 who have a 20 pack-year smoking history should be screened every year, providing they currently smoke or quit smoking within the last 15 years. It’s a significant update to their previous recommendation of yearly screening for adults aged 55–80 years with a 30 pack-year smoking history.

A “pack-year” is a unit of measurement used to estimate a person’s smoking history based on packs smoked per day. One pack-year is equal to 20 cigarettes per day (considered a standard pack) in a single year, so a person with a 20 pack-year smoking history might have smoked a pack a day for 20 years, or two packs per day for 10 years. 

Lung cancer is a major public health issue in the US, accounting for the most cancer deaths in the country; in 2020, the US Department of Health estimates 135,720 Americans died from the disease. Screening is a thorny issue for US health authorities, with a recent study of 10 states revealing that only around 15% of eligible people were actually being screened for lung cancer. 

The new advice is based on a number of studies, including two major randomised controlled trials that found that screening earlier – and with a lower pack-year threshold – could reduce lung cancer mortality rates. 

Modelling by the task force (an independent panel of experts that periodically reviews the effectiveness of clinical preventive services) suggests the new recommendations would reduce lung cancer mortality by 13%, compared with the 9.8% reduction produced by the previous recommendations – equivalent to an extra 2,036 life-years gained.

The new recommendations may also go some way to bridging the gap in health outcomes between white and black Americans, because black people who smoke have a statistically higher risk of developing lung cancer – and the risk disparity is particularly pronounced at lower smoking history thresholds.

The findings raise questions about the applicability of these recommendations elsewhere. Lung cancer is Australia’s fifth most commonly diagnosed cancer but it causes more deaths than any other type.

The Australian Government and Cancer Australia’s Lung Cancer Screening enquiry was completed in 2020 and its report delivered to Minister for Health Greg Hunt in October.

The report recommends the establishment of a national lung cancer screening program. It’s estimated that, in the first 10 years of such a program, over 12,000 lung cancer deaths would be prevented and 30,000–50,000 quality adjusted life years would be gained. 

If the proposal went ahead, Australia could be among the first nations in the world to introduce such a program. 

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