Estimated impact of LDCT-identified stage IA non-small-cell lung cancer on screening efficacy

About one-third of individuals radiographically diagnosed with surgical-pathological stage IA non-small-cell lung cancer (IA-NSCLC) harbor occult metastases that prove lethal. A comparison of the projected outcome of CT-diagnosed IA-NSCLC with actuarial figures for life expectancy of screenees suggests that about half of the remainder will succumb to alternative causes. CT screening can be efficacious if and only if it leads to an interdiction of potentially lethal cancers in the remaining one-third of sufficient magnitude that it offsets the surgical mortality and abbreviation of life expectancy in the two-thirds who are either understaged or overdiagnosed. Preliminary evidence from CT screening trials fails to support the premise that it diminishes the absolute number of advanced lung cancers.