Screening for Lung Cancer
It has long been established that the best way to control lung cancer is to reduce cigarette smoking in the population, foremost through prevention, and secondarily through smoking cessation. However, even after stopping smoking longterm smokers remain at high risk of lung cancer. Lung cancer when clinically diagnosed has a poor outcome with 10–16% survival at 5 years. If the tumour is small enough to be removed surgically, the outcome is much better, >70% for stage I tumours. This led to speculation in the past as to whether long-term smokers or others at high risk might benefit from earlier detection.
Low-dose spiral CT scanning can detect lung cancer at an early stage. The Early Lung Cancer Action Project (ELCAP) demonstrated that spiral CT was able to identify very small lung cancers in high-risk volunteers, with a resectability rate of 96% and a proportion of stage I >80%. An initial high false-positive rate was reduced by high-resolution CT (HRCT) with a complex algorithm of 3D reconstruction for tumour growth. Randomised trials of spiral CT using a non-intervention control group and with lung cancer mortality as the trial outcome are needed to determine the value of this method of screening.