NELSON

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​The NELSON study is a Dutch-Belgian population-based, randomised controlled lung cancer screening trial. Starting in​ 2003, the trial spanned over a decade and comprised of 15,792 (ex-)smokers at risk of lung cancer. Its main objective was to reduce the lung cancer specific mortality by 25% compared to the unscreened control group [1]. Participants were randomized 1:1 in a screening and control group. Subjects who were selected for the screening were periodically invited to undergo low dose computed tomography (CT) scans from the chest. Both groups (the screen participants and the controls) filled out questionnaires at the start of the trial and at the follow up after 10 years.

More specifically, the population comprised of people born between 1928 and 1956 originating the Netherlands and Belgium, who:

  • smoked > 15 cigarettes/day during > 25 years,
  • or smoked > 10 cigarettes/day during > 30 years, 
  • and were current smokers or former smokers who quit smoking ≤ 10 years ago. 

Excluded were those with a moderate or bad self-reported health who were unable to climb two flights of stairs, those with a body weight ≥ 140 kilograms, with current or past renal cancer, melanoma or breast cancer, or with lung cancer diagnosed less than 5 years ago, or 5 years or more ago but still under treatment. Also those who had a chest CT examination less than one year before they filled in the first NELSON questionnaire were excluded.

Participants from the screening group were invited for a diagnostic test at years 1, 2, 4, and 6 [1], as shown in the figure. No scans were made in the control group as part of the trial.


Screen test results that were indeterminate resulted in a short-term follow up CT​ screening​ 3-4 months later (not shown in the figure).

Data access

Access to data from the de-identified dataset―comprised of CT scans and annotated data of the participants in the screening group, and questionnaires of all subjects― can be requested by researchers​ through an application to the Data Access Board (DAB). ​

More de​tails of the dataset

  1. Y. R. Zhao et al., NELSON lung cancer screening study, Cancer Imaging 11, S79 (‘11).
  2. C. A. van Iersel et al., Risk‐based selection from the general population in a screening trial: Selection criteria, recruitment and power for the Dutch‐Belgian randomised lung cancer multi‐slice CT screening trial (NELSON), Int. J. Cancer 120,868 (‘06).
  3. D. M. Xu et al., Nodule management protocol of the NELSON randomised lung cancer screening trial, Lung Cancer 54, 177 (‘06).​