{'fraction_non_alphanumeric': 0.02437880918893577, 'fraction_numerical': 0.016408813877168308, 'mean_word_length': 5.332344213649852, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Defining the path: lung cancer CT screening in Europe

Since the publication of the National Lung Screening Trial (NLST) in 2011 demonstrating a 20% reduction in lung cancer-specific mortality by annual low-dose CT (LDCT),1 implementation of screening has continued apace in the USA. Other developed nations, perhaps mindful of the potential cost implications of national screening programmes, have been more reticent, with many awaiting the final outcome data from the largest European randomised trial—the Dutch-Belgian Lung Cancer Screening trial (NELSON)  study which remains in follow-up.2 

Despite the convincing mortality reduction in NLST, questions remain about implementation of LDCT screening for lung cancer. Unresolved issues include how to best identify high-risk individuals for screening, what is the most appropriate screening interval to achieve an optimal balance between mortality reduction and cost-effectiveness and how to minimise possible harms associated with screening—particularly overdiagnosis. This issue of Thorax includes two papers which provide important additions to accumulating evidence in this field.

Paci and colleagues3 report lung cancer incidence and mortality rates from the Italian Lung Cancer Screening Trial (ITALUNG) randomised lung cancer screening trial conducted in Tuscany, Italy, commencing in 2004. From an invited population of over 71 232 subjects aged 55–69 years, 1613 were randomised to four rounds of annual LDCT screening and 1593 to usual care. Like many of the other European screening studies, ITALUNG was not powered to demonstrate mortality reduction in isolation, and pooled analysis with other similarly designed randomised trials is planned.

As expected, lung cancer incidence was higher in the intervention group during the 4-year screening period (55% excess diagnoses vs usual care group). However, this was followed by a compensatory reduction in diagnoses during the 5-year follow-up period, such that there was no significant difference in incidence rates between the groups at the end of the study. After a median follow-up of 9 years, the authors report …