Stellungnahme der Österreichischen Röntgengesellschaft und der Österreichischen Gesellschaft für Pneumologie

European lung cancer screening: valuable trial evidence for optimal practice implementation

Lung cancer screening (LCS) by low-dose computed tomography is a strategy for secondary prevention of lung cancer. In the last two decades, LCS trials showed several options to practice secondary prevention in association with primary prevention, however, the translation from trial to practice is everything but simple. In 2020, the European Society of Radiology and European Respiratory Society published their joint statement paper on LCS. This commentary aims to provide the readership with detailed description about hurdles and potential solutions that could be encountered in the practice of LCS.

Do doctors understand the test characteristics of lung cancer screening?

BACKGROUND

Screening for lung cancer with a low-dose computed tomography (CT) scan is estimated to prevent 3 deaths per 1000 individuals at high risk; however, false positive results and radiation exposure are relevant harms and deserve careful consideration. Screening candidates can only make an autonomous decision if doctors correctly inform them of the pros and cons of the method; therefore, this study aimed to evaluate whether doctors understand the test characteristics of lung cancer screening.

METHODS

In a randomized trial 556 doctors (members of the Austrian Respiratory Society) were invited to answer questions regarding lung cancer screening based on online case vignettes. Half of the participants were randomized to the group 'solutions provided' and received the correct solutions in advance. The group 'solutions withheld' had to rely on prior knowledge or estimates. The primary endpoint was the between-group difference in the estimated number of deaths preventable by screening. Secondary endpoints were the between-group differences in the prevalence of lung cancer, prevalence of a positive screening results, sensitivity, specificity, positive predictive value, and false negative rate. Estimations were also compared with current data from the literature.

RESULTS

The response rate was 29% in both groups. The reduction in the number of deaths due to screening was overestimated six-fold (95% confidence interval CI: 4-8) compared with the actual data, and there was no effect of group allocation. Providing the correct solutions to doctors had no systematic effect on their answers.

CONCLUSION

Doctors poorly understand the test characteristics of lung cancer screening. Providing the correct solutions in advance did not improve the answers. Continuing education regarding lung cancer screening and the interpretation of test characteristics may be a simple remedy.

CLINICAL TRIAL REGISTRATION

Clinical trial registered with www.clinicaltrials.gov (NCT02542332).

Lung Cancer Screening Using Low Dose CT Scanning in Germany. Extrapolation of results from the National Lung Screening Trial

BACKGROUND

It is now debated whether the screening of heavy smokers for lung cancer with low dose computed tomography (low dose CT) might lower their mortality due to lung cancer. We use data from the National Lung Screening Trial (NLST) in the USA to predict the likely effects of such screening in Germany.

METHODS

The number of heavy smokers aged 55-74 in Germany was extrapolated from survey data obtained by the Robert Koch Institute. Published data from the NLST were then used to estimate the likely effects of low dose CT screening of heavy smokers in Germany.

RESULTS

If low dose CT screening were performed on 50% of the heavy smokers in Germany aged 55-74, an estimated 1 329 506 persons would undergo such screening. If the screening were repeated annually, then, over three years, 916 918 screening CTs would reveal suspect lesions, and the diagnosis of lung cancer would be confirmed thereafter in 32 826 persons. At least one positive test result in three years would be obtained in 39.1% of the participants (519 837 persons). 4155 deaths from lung cancer would be prevented over 6.5 years, and the number of persons aged 55-74 who die of lung cancer in Germany would fall by 2.6%. 12 449 persons would have at least one complication, and 1074 persons would die in the 60 days following screening.

CONCLUSION

The screening of heavy smokers for lung cancer can lower their risk of dying of lung cancer by 20% in relative terms, corresponding to an absolute risk reduction of 0.3 percentage points. These figures can provide the background for a critical discussion of the putative utility of this type of screening in Germany.