Lung cancer screening with low-dose CT: Simulating the effect of starting screening at a younger age in women

Background: The US has recently lowered the entry age for lung cancer screening with low-dose computed tomography (LDCT) from 55 to 50 years. The effect of the younger age for starting screening on the rates of screen-detected and radiation-induced lung cancers in women remains unclear. Methods: A modeling study was conducted. A static cohort of 100,000 heavy female smokers was simulated to undergo annual lung cancer screening with LDCT. The number of screen-detected lung cancers (benefit) and radiation-induced lung cancers (harm) per 1000 screenees were calculated for scenarios with two starting ages (55-50 years) and fixed stopping age (75 years). The benefit-harm ratio and incremental benefit-harm ratio (IBHR) were calculated for each scenario. Results: For annual screening from 55 to 75 years, the number of screen-detected and radiation-induced lung cancers was 112.4 and 2.2, respectively. For annual screening from 50 to 75 years, those numbers were 117.0 and 3.4, respectively. The benefit-harm ratio decreased from 51 to 35 and the IBHR decreased from 6.3 to 4.0 when lowering the screening starting age from 55 to 50 years. Conclusions: The risk of radiation induced lung cancers increased by 50% when lowering the screening starting age by 5 years in women. However, the benefits of LDCT lung cancer screening still outweigh the assumed radiation harm.

Automated summary

Lowering the screening starting age from 55 to 50 years increases the risk of radiation-induced lung cancers in women by 50%. However, the benefits of LDCT lung cancer screening still outweigh the assumed radiation harm.