Low-dose CT for lung cancer early-detection in China: Findings from a screening program in Shanghai

BACKGROUND: Low-dose computed tomography (LDCT) has been recommended for lung cancer screening in high-risk populations. This study is aimed to evaluate the effects of LDCT screening for lung cancer in Chinese populations. METHODS: A total of 26124 subjects aged over 40 years were enrolled from the Minhang District of Shanghai, China, 2013-2017. The detection of lung cancer and the survival status of cases up to Dec 31,2018 were obtained. Standardized incidence ratio (SIR) was calculated for the screened populations relative to the local general population. Three-year survival rates and proportion of early-stage (stage 0-I) cancer were estimated for all cases from general population and for screen-detected cases. For 12184 high-risk individuals in the screened population, a total of 12184 matched controls without LDCT were identified using propensity score matching (PSM), lung cancer mortality and all-cause mortality were calculated and compared between groups. RESULTS: The crude incidence of lung cancer in the screened population was 426.6 (95%CI: 387.4-470.2) per 100000 person-years, with an overall SIR of 2.3 (95%CI: 2.0-2.5). The SIR decreased with the highest level in the first year [3.8 (95%CI: 3.3-4.3)], and a lower level over 3 years [0.6 (95%:CI: 0.5-0.7)]. Early-stage lung cancer accounted for 26.3% of screen-detected cases, significantly higher than 15.3% in all cases during the same period. The 3-year survival rate was also higher in screen-detected cases (60.4%) than all cases (50.9%). Compared with the matched control group, the screened group had a 32.0% (95%CI: 0.47- 0.99) reduced lung cancer mortality and a 56% (95%CI: 0.37-0.52) decreased all-cause mortality. The proportion of early-stage lung cancer was also higher in cases screened-detected than in non-screened (28.9% vs 11.8%, p < 0.05). CONCLUSIONS: Our results prove the benefits of LDCT screening and its great potential in reducing the disease burden of lung cancer in Chinese populations. KEY MESSAGES: • LDCT screening improved the detection of lung cancer in Chinese populations, and increased the proportion of early-stage cancer and 3-year survival rate of detected lung cancer cases. • LDCT screening decreased 32% of lung cancer mortality and 56% of all-cause mortality in Chinese populations.