CT screening for lung cancer brings forward early disease. The randomised Danish Lung Cancer Screening Trial: status after five annual screening rounds with low-dose CT
- Zaigham Saghir1,
- Asger Dirksen1,
- Haseem Ashraf2,
- Karen Skjøldstrup Bach3,
- John Brodersen4,
- Paul Frost Clementsen1,
- Martin Døssing5,
- Hanne Hansen6,
- Klaus Fuglsang Kofoed7,
- Klaus Richter Larsen8,
- Jann Mortensen9,
- Jakob Fraes Rasmussen4,
- Niels Seersholm1,
- Birgit Guldhammer Skov10,
- Hanne Thorsen4,
- Philip Tønnesen1,
- Jesper Holst Pedersen11
- 1Department of Respiratory Medicine, Gentofte University Hospital, Hellerup, Denmark
- 2Department of Radiology, Akershus University Hospital, Lørenskog, Norway
- 3Department of Radiology, Gentofte University Hospital, Hellerup, Denmark
- 4The Research Unit and Section for General Practice, Department of Public Health, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- 5Department of Internal Medicine, Nordsjælland University Hospital, Frederikssund, Denmark
- 6Department of Radiology, Bispebjerg University Hospital, Copenhagen, Denmark
- 7Department of Cardiology, Copenhagen University Hospital, Copenhagen, Denmark
- 8Department of Respiratory Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
- 9Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital, Copenhagen, Denmark
- 10Department of Pathology, Bispebjerg University Hospital, Copenhagen, Denmark
- 11Department of Thoracic Surgery, Copenhagen University Hospital, Copenhagen, Denmark
- Correspondence to Dr Zaigham Saghir, Department of Respiratory Medicine, Gentofte University Hospital, Niels Andersens Vej 65, Opgang 30A, 2900 Hellerup, Denmark;
Contributors Steering Committee (initiated trial design, data collection and statistical analysis plan): Jesper Holst Pedersen (Chairman/PI/Guarantor), Asger Dirksen (Guarantor), Karen Skjøldstrup Bach, John Brodersen, Paul Frost Clementsen, Martin Døssing, Hanne Hansen, Klaus Fuglsang Kofoed, Klaus Richter Larsen, Jann Mortensen, Niels Seersholm, Birgit Guldhammer Skov, Hanne Thorsen, Philip Tønnesen, Haseem Ashraf (2007) and Zaigham Saghir (2009/Guarantor). HH and KSB performed reading of CT scans. AD, PFC, KRL, JM, NS, BGS, PT conducted diagnostic workup. AD was responsible of event monitoring and following protocol. JB and HT designed the COS and COS-LC questionnaires. ZS and HA collected, cleaned and analysed data. JFR collected data. ZS drafted and revised the paper. All revised the paper.
- Received 3 July 2011
- Accepted 14 December 2011
- Published Online First 27 January 2012
Background The effects of low-dose CT screening on disease stage shift, mortality and overdiagnosis are unclear. Lung cancer findings and mortality rates are reported at the end of screening in the Danish Lung Cancer Screening Trial.
Methods 4104 men and women, healthy heavy smokers/former smokers were randomised to five annual low-dose CT screenings or no screening. Two experienced chest radiologists read all CT scans and registered the location, size and morphology of nodules. Nodules between 5 and 15 mm without benign characteristics were rescanned after 3 months. Growing nodules (>25% volume increase and/or volume doubling time<400 days) and nodules >15 mm were referred for diagnostic workup. In the control group, lung cancers were diagnosed and treated outside the study by the usual clinical practice.
Results Participation rates were high in both groups (screening: 95.5%; control: 93.0%; p<0.001). Lung cancer detection rate was 0.83% at baseline and mean annual detection rate was 0.67% at incidence rounds (p=0.535). More lung cancers were diagnosed in the screening group (69 vs 24, p<0.001), and more were low stage (48 vs 21 stage I–IIB non-small cell lung cancer (NSCLC) and limited stage small cell lung cancer (SCLC), p=0.002), whereas frequencies of high-stage lung cancer were the same (21 vs 16 stage IIIA–IV NSCLC and extensive stage SCLC, p=0.509). At the end of screening, 61 patients died in the screening group and 42 in the control group (p=0.059). 15 and 11 died of lung cancer, respectively (p=0.428).
Conclusion CT screening for lung cancer brings forward early disease, and at this point no stage shift or reduction in mortality was observed. More lung cancers were diagnosed in the screening group, indicating some degree of overdiagnosis and need for longer follow-up.
- Lung neoplasms
- mass screening
- randomised controlled trial
- clinical epidemiology
- imaging/CT MRI
- lung cancer
- non-small cell lung cancer
- small cell lung cancer
- alpha1 antitrypsin deficiency
- inhaler devices
- pulmonary embolism
- clinical epidemiology
- lung cancer
- tobacco and the lung
- lung proteases
See Editorial, p 283
Funding This study was supported by the Danish Ministry of Interior and Health.
Competing interests None.
Ethics approval Ethics approval was provided by Committee of Copenhagen County and the Danish Data Protection Agency.
Provenance and peer review Not commissioned; externally peer reviewed.