Long-Term Follow Up of an Occupational Cohort in Yunnan, People’s Republic of China: 20-Year Postscreening Follow Up and 8-Year Lung Cancer Screening

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.