P1.03-039 Is It Necessary to Repeat Lung Cancer Screening with Low-Dose CT(LDCT) in Female Never Smokers?

Abstract

Lung cancer (LC) screening is not recommended for low-risk subjects, including never smokers. However, LDCT is often performed in Korea as a part of cancer screening program even for healthy female never smokers (FNS). To examine the role of LDCT screening in FNS, we estimated the risk of subsequent development of LC according to their initial LDCT findings and age groups. This retrospective cohort study included FNS aged 40 to 79 years who performed initial LDCT from Aug 2002 to Dec 2007. Lung cancer diagnosis was identified from the Korea Central Cancer Registry Database (Dec 2013) and vital status (Dec 2014) from Statistics Korea. LDCT findings were reviewed using Lung Imaging Reporting and Data System (Lung-RADS). LC risk and outcomes were analyzed according to initial LDCT findings and age groups using the national data up to 12 years after the LDCT. There were 4,365 FNS with mean age of 51.1±7.6 years (median F/U time = 9.7 years). Overall, twenty-two LCs (0.5%) were identified with an incidence rate of 52.58 (95% CI 34.62-79.86) per 100,000 person-years. The incidence rates were 8.53 (2.75-26.44), 75.16 (24.24-233.04), 0 and 1665.58 (1020.38-2718.72) in subjects with category 1, 2, 3 and 4, respectively. The cumulative incidence is shown in Fig 1. The incidence rates were 35.30 (95% CI 18.99-65.00) and 88.84 (50.45-156.44) in age with 40∼54 years and 55∼79, respectively. Three women among 16 classified into category 4 died of LC, while no death in those with category 1, 2, or 3 [median time to LC diagnosis= 5.1 years (range, 2.8-8.8)]. Although, the effectiveness of lung cancer screening is in FNS still unclear, repeat LDCT seems to be unnecessary in those with category 1, 2 and 3, at least within 5 years after initial LDCT.