Lung cancer screening with low dose computed tomography

Lung cancer is a health problem that clearly merits a screening programme. Each year about 35 000 people in the United Kingdom die from lung cancer—more than the number for colorectal and breast cancer combined. In addition, about three quarters of people present with incurable disease, at a stage when treatment has little effect on overall survival; early stage disease is curable; risk factors for lung cancer are well understood; and a highly sensitive screening test is available.

Many of the early trials of screening with chest radiography and the non-randomised computed tomography studies were not designed to minimise the biases operating in screening trials that result in apparently longer survival but no reduction in mortality. The answer to this problem was to design randomised controlled trials with disease specific mortality as the endpoint.

The National Lung Screening Trial (NLST) randomised more than 53 400 people in the United States aged 55-74 years who had smoked in the past 15 years and had accumulated a minimum of 30 pack years to three annual screens with low dose computed tomography or chest radiography.1 The trial recruited between 2002 and 2004, and in October 2010 …