Studies have shown that chest x-ray screening does not improve mortality statistics. However, studies in Japan and United States (Mayo, Cornell) have shown that CT scanning can detect cancers in stage 1 when cure rates are very high. The ELCAP trial (early lung cancer action program) was designed to evaluate baseline and annual repeat screening by low dose CT in persons at high risk for lung cancer. The study published in Lancet (1999) found that 74% of the CT detected cases of lung cancer were not seen on chest x-ray. The investigators of ELCAP have concluded "annual CT screening for lung cancer in high risk individuals provides for detecting the disease at earlier and presumably more commonly curable stages in a cost-effective manner".

Although not all evidence for EBT and CT screening is yet available, it is clear that these techniques can detect lung cancer and nodules smaller than 5 mm when cure rates approach 85%. Early detection commonly leads to cure.