Disparity in Lung Cancer Screening Among Smokers and Nonsmokers in China: Prospective Cohort Study

Abstract

Background Low-dose computed tomography (LDCT) screening is effective in reducing lung cancer mortality in smokers; however, the evidence in nonsmokers is scarce. Objective This study aimed to evaluate the participant rate and effectiveness of one-off LDCT screening for lung cancer among smokers and nonsmokers. Methods A population-based prospective cohort study was performed to enroll participants aged between 40 and 74 years from 2013 to 2019 from 4 cities in Zhejiang Province, China. Participants who were evaluated as having a high risk of lung cancer from an established risk score model were recommended to undergo LDCT screening. Follow-up outcomes were retrieved on June 30, 2020. The uptake rate of LDCT screening for evaluated high-risk participants and the detection rate of early-stage lung cancer (stage 0-I) were calculated. The lung cancer incidence, lung cancer mortality, and all-cause mortality were compared between the screened and nonscreened groups. Results At baseline, 62.56% (18,818/30,079) of smokers and 6% (5483/91,455) of nonsmokers were identified as high risk (P<.001), of whom 41.9% (7885/18,818) and 66.31% (3636/5483) underwent LDCT screening (P<.001), respectively. After a median follow-up of 5.1 years, 1100 lung cancer cases and 456 all-cause death cases (116 lung cancer death cases) were traced. The proportion of early-stage lung cancer among smokers was 60.3% (173/287), which was lower than the proportion of 80.3% (476/593) among nonsmokers (P<.001). Among smokers, a higher proportion was found in the screened group (72/106, 67.9%) than the nonscreened group (56/114, 49.1%; P=.005), whereas no significance was found (42/44, 96% vs 10/12, 83%; P=.20) among nonsmokers. Compared with participants who were not screened, LDCT screening in smokers significantly increased lung cancer incidence (hazard ratio [HR] 1.39, 95% CI 1.09-1.76; P=.007) but reduced lung cancer mortality (HR 0.52, 95% CI 0.28-0.96; P=.04) and all-cause mortality (HR 0.47, 95% CI 0.32-0.69; P<.001). Among nonsmokers, no significant results were found for lung cancer incidence (P=.06), all-cause mortality (P=.89), and lung cancer mortality (P=.17). Conclusions LDCT screening effectively reduces lung cancer and all-cause mortality among high-risk smokers. Further efforts to define high-risk populations and explore adequate lung cancer screening modalities for nonsmokers are needed.

Impact of annual trend volume of low-dose computed tomography for lung cancer screening on overdiagnosis, overmanagement, and gender disparities

“…To reduce the potential for overdiagnosis, especially among women younger than 40 years, implementing more rigorous risk prediction models and considering raising the screening age threshold for nonsmoking female populations when it comes to lung cancer screening is advised [ 21 ]. Heavy smokers may be less willing to participate in lung cancer screening programs [ 32 ]; therefore, increasing screening rates among heavy smoking populations is an important issue [ 21 ]. However, for nonsmoking populations in Asia, where concerns about lung cancer are collective, screening efficiency must be optimized based on risk-prediction models tailored for nonsmokers and health education must be provided to reduce screening reluctance and anxiety among this group [ 21 ].…”

Association between non-alcoholic fatty liver disease and the risk of pulmonary nodules in patients with intestinal polyps

“…Due to developments in and the increasing utility of computer tomography (CT) in most countries, the detection of pulmonary nodules is now the most important early indicator of lung cancer ( 15 , 16 ). It is well documented that smoking and genetic risk factors are risk factors of lung cancer ( 17 , 18 ). Further, a narrative review showed that the association between obesity and lung cancer risk and prognosis depends on age, gender, race, and the metrics used to measure obesity ( 19 ).…”