Less ‘harm’ from lung cancer screening than trials suggested 

Lung cancer

By Emma Wilkinson

15 Feb 2021

The ‘harms’ of screening for lung cancer such as overdiagnosis are much lower in real-world implementation than were suggested in large RCTs, UK researchers report.

Presenting combined real-world data from five UK pilot sites at the 2020 World Conference on Lung Cancer, researchers reported an overall lung cancer detection rate of 2.1%.

The analysis of 11,815 low dose CT screens carried out in the pilot sites between 2016 and 2020 also showed a false positive rate of 1.9% – significantly lower than that reported in screening trials done in Europe and the US.

Harm from investigation and treatment of non-malignant disease was minimised with no reported major complications or deaths, the researchers reported in Thorax.

Knowing when to intervene

Speaking with the limbic, Dr Matthew Evison, consultant chest physician at Wythenshawe Hospital and British Thoracic Society special advisory group member, said the difference in the latest UK figures and those from previous trials was related to better knowledge of when to treat and when to leave alone.

The US National Lung Screening Trial, which is often cited as evidence by those arguing screening does more harm than good, was also published quite a few years ago in 2011, he added.

“Trials such as NLST and NELSON have categorically shown a reduction in lung cancer mortality, that debate is done,” he said. “The central argument has always been at what cost does that come from when you look at the harms of screening.

“It’s such an important question. We have learnt so much about nodule management and when not to do surgery. Now we have real life data and that is going to be really powerful in this debate.”

Data for the study was taken from the UK Lung Cancer Screening Trial (UKLS), Lung Screen Uptake Trial, Manchester Lung Health Checks, Liverpool Healthy Lung Project, and Nottingham Lung Health MOT.

Positive results were defined as those referred for more than a repeat low-dose CT screen, and false positives were those without an eventual diagnosis of lung cancer. 

Harms were categorised as the need for further imaging, invasive investigations, and/or surgery. 

Overall, 85.5% of screening scans were categorised as negative, 10.5% as indeterminate, and 4% as positive. Lung cancer detection was 2.1% (ranging from 1.7% to 4.4% across sites) and the surgical resection rate was 66.0%.


A table of ‘harms’ showed a rate of invasive investigation for benign disease (excluding surgery) of 0.5% and that 8 patients had surgical resection for benign disease (0.07% of all scans or 4.6% of surgeries).

The data “provides reassurance that with the use of evidence-based practice and experienced MDTs, harms from false positive results can be minimised within screening. 

“This information is important in the planning of larger scale implementation of lung cancer screening within the UK and beyond,” the researchers concluded.

NELSON was one trial that afforded those undertaking lung cancer screening excellent data on nodule management, said Dr Evison, who leads one of the sites that fed data into the latest analysis.

“The vast majority are benign so it is about knowing how to pick out those that are benign and that you can leave alone versus the cancers you want to go after and we have learnt how to minimise harm and have developed BTS nodule management guidelines for multidisciplinary teams to follow,” he told the limbic.

This is a really important piece of work – not to be taken in isolation, but it is a key part of the jigsaw.”

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