Overdiagnosis of Lung Cancer Due to the Introduction of Low-Dose Computed Tomography in Average-Risk Populations in the People's Republic of China.

INTRODUCTION

Low-dose computed tomography (LDCT) has been widely used in health check-ups in China since 2011. The introduction of LDCT in average-risk populations may have led to substantial overdiagnosis of lung cancer.

METHODS

This registry-based study included 46,978 incident cases and 34,475 deaths of lung cancer derived from a population of approximately 3.21 million in the Pudong New Area of Shanghai, People's Republic of China, from 2002 to 2020. We calculated the age-standardized rates of overall, stage- and histology-specific incidence and overall mortality by sex. The numbers and proportions of cases attributable to overdiagnosis were estimated on the basis of the comparison between the shape of the age-specific curve with that before the introduction of LDCT in average-risk populations since 2011.

RESULTS

The age-standardized incidence of lung cancer increased rapidly since 2011 in both male and female individuals, whereas the age-standardized mortality declined over the period. The upward trends in incidence were mainly observed in women with early-stage cancer and lung adenocarcinoma. Overall, no significant overdiagnosis was observed in men, whereas the overdiagnosis rate grew from 22% in 2011 to 2015 to 50% in 2016 to 2020 in women. Further analysis reported elevated numbers (proportions) of lung adenocarcinoma cases attributable to overdiagnosis, which rose from 182 cases (8%) in 2011 to 2015 to 827 cases (22%) in 2016 to 2020 in men, and from 1842 cases (85%) to 4171 cases (89%) in women.

CONCLUSION

This study demonstrates considerable and increasing overdiagnosis of lung adenocarcinoma in Chinese men and women. The guideline is urgently needed to maximize the benefits of LDCT screening and reduce the potential overdiagnosis of lung cancer.