Figure 1:

Like an iceberg, the bulk of cases of lung cancer are not only not detected by screening, but occur in patients not eligible for screening. Approximately 4% of NLST-eligible patients undergo screening. If all NLST-eligible patients underwent screening, only 27% of lung cancers would be detected, similar to the portion of an iceberg seen above water. The remaining 73% of lung cancers occur in those ineligible for screening, for instance those with only a light smoking history, those who have quit > 15 years ago, or those who have never smoked. Biomarkers in high-risk individuals can decrease the rate of false positives after CT-based screening. In lower-risk individuals, biomarkers can be used to identify patients at higher risk who may benefit from screening.