Overdiagnosis of Lung Cancer due to Introduction of Low-Dose Computed Tomography in Average-Risk Populations in China.

Abstract

Background: 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, 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 based on the comparison between the shape of the age-specific curve with that prior to the introduction of LDCT in average-risk populations since 2011.

Results: The age-standardized incidence of lung cancer increased rapidly since 2011 in both males and females, while the age-standardized mortality declined over the period. The upward trends in incidence were mainly observed in women for early-stage cancer and for lung adenocarcinoma. Overall, no significant overdiagnosis was observed in men, whereas the overdiagnosis rate grew from 22% in 2011-2015 to 50% in 2016-2020 in women. Further analysis showed elevated numbers (proportions) of lung adenocarcinoma cases attributable to overdiagnosis, which rose from 182 (8%) in 2011-2015 to 827 (22%) in 2016-2020 in men, and from 1,842 (85%) to 4,171 (89%) in women. ConclusionThis 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.