Lung cancer screening widened to target younger smokers 

Lung cancer

By Dave Levitan

18 Mar 2021

The US Preventive Services Task Force has updated a recommendation on low-dose CT (LDCT) lung cancer screening that has stood since 2013, lowering the age threshold and reducing the required degree of smoking history – but some experts think the guidelines still unintentionally discriminate too much based on sex and ethnicity.

The USPSTF updated its recommendation to change the lower age threshold for screening from 55 to 50. It also changed the smoking history requirement, from 30 pack-years to 20 pack-years; it still includes people who currently smoke or who have quit within the past 15 years.

Experts say the change to the guideline will increase the number of eligible individuals in the US by 86%. Modelling suggests that while the original recommendation could avert 9.8% of lung cancer deaths, the new version would increase that to 13.0%.

“Perhaps the greatest consequence of the new guidelines is that the inclusion of younger smokers and those with a lower smoking exposure have the biggest effect on the number of women and racial/ethnic minorities eligible for screening,” wrote cancer specialists led by Dr Yolonda Colson, of Massachusetts General Hospital and Harvard Medical School, in an editorial in JAMA Surgery.

Those groups develop lung cancer at an earlier age and with lower smoking histories than the predominantly White and male populations that were tested in the National Lung Cancer Screening Trial (NLST), on which the guidelines were originally based. In the UK, lung cancer incidence rates have decreased overall since the early 1990s, but rates in females have increased by 31% while they fell by 33% in males.

Dr Colson and her colleagues noted, however, that the guidelines still exclude people by excluding additional risk factors such as occupational and environmental exposures such as radon.

“For the 15% to 20% of patients with lung cancer who have never smoked, especially women, these new guidelines continue to be inadequate and do not provide guidance on screening for nonsmoking populations at risk for lung cancer,” they wrote.

In Australia, respiratory physicians and oncologists are following the progress of the recently released Cancer Australia Report on lung cancer screening, which was  presented to the Health Minister in October 2020 and is awaiting action.

The enquiry proposed implementation of a screening program that would target people in the 55 to 74 years age group who are current or former smokers (50 to 74 years for Aboriginal and Torres Strait Islander population).

This would result in approximately 2.9 million men and women, of whom an estimated 580,000 would be eligible for LDCT upon completion of the risk assessment tool.

A recent podcast from the Thoracic Oncology Group of Australia (TOGA) discusses the issues around lung cancer screening trials currently underway in Australia and the progress towards implementation of screening. It is hosted by Dr Emily Stone, Respiratory Physician from St Vincent’s Hospital in Sydney, who interviews Professor Kwun Fong, Thoracic and Sleep Physician at The Prince Charles Hospital, Brisbane.

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