Screening for lung cancer: Individualized benefit by risk indicators for the first round of screening

Abstract

7064 Background: The I-ELCAP investigators at 35 institutions throughout the world have been performing CT screening for lung cancer to evaluate its usefulness and to determine the benefit of undergoing the first round of screening given a person’s individual risk indicators. Methods: Baseline screening has been performed on 27,701 high-risk men and women (age, smoking history) between 1993–2004. A lung cancer diagnosis was classified as a baseline screen-diagnosed case if the work-up was prompted by a positive result on the initial CT. Prevalence of lung cancer on baseline screening was determined by age (40–49, 50–74, 75+ years) and smoking history (1–29, 30–59, 60+ pack-years). Kaplan-Meier analysis was applied to resected cases of lung cancers of Stage I to determine lung cancer case-fatality rate. The benefit of a single round of screening was determined by the estimated probability of detecting a lung cancer, of it being of Stage I, of being cured of the cancer following its resection and not dying of non-lung cancer causes (e.g., cardiovascular, stroke) in the 10 years following that round of screening. Results: The benefit of screening ranged from 0.15% for those of age 40–49 with a history of less than 60 pack-years of smoking and increased to 0.76% for this age group with a 60+ pack-year smoking history. Similarly for those aged 50–74, it ranged from 0.88% to 2.0%, with the benefit increasing with increasing age and pack-years of smoking. The same trend was seen for those 75+ for whom it ranged from 1.3% to 2.1%. Conclusions: This approach provides the estimated probability that the first round of screening will save a person’s life based on the individual risk indicators. No significant financial relationships to disclose.