PURPOSE There is no long-term, population-based cohort screening evidence for lung cancer in China. This study aimed to evaluate whether increased screening rounds could reduce mortality as a result of lung cancer. METHODS We conducted a one-armed, prospective lung cancer screening cohort study with chest radiography and sputum cytology in Yunnan, People’s Republic of China, from 1992 to 1999. A total of 9,295 tin miners age 40 years or older were enrolled in this study and follow up ended on December 31, 2018. We stratified patients into 4 subgroups on the basis of screening rounds—1-2, 3-4, 5-6, or 7-8 rounds within 8 years—and selected 1-2 screening rounds within 8 years as the control group. Hazard ratios (HRs) and 95% CIs for the effect of screening rounds on mortality were estimated using Cox proportional hazards regression models. RESULTS Of participants, 831 (8.9%) were lost to follow up, and 4,517 patients died, 1,600 from cancer (1,135 from lung cancer), 1,519 from circulatory system diseases, and 619 from respiratory diseases. Participants who received 7-8 screening rounds within 8 years had reduced lung cancer mortality by 46% (HR, 0.54; 95% CI, 0.46 to 0.63 in all age groups. For those who received 5-6 screening rounds within 8 years, the benefit of reduction was mostly observed in patients older than age 52 years (HR, 0.63; 95% CI, 0.52 to 0.77), and there was no effect among those age 52 years or younger (HR, 0.72; 95% CI, 0.48 to 1.07). In contrast, only for those patients age 52 years or younger did 3-4 screening rounds within 8 years decrease mortality from lung cancer (HR, 0.56; 95% CI, 0.36 to 0.87). CONCLUSION We showed that increased screening rounds could reduce lung cancer mortality in a high-risk population, but the effect is influenced by age group. The optimal screening strategy for different age groups needs additional investigation.
Complement C3 Genotype Variants and Risk of Lung Cancer Mortality
