Lung cancer screening with low-dose computed tomography at a tertiary hospital in Anhui, China and secondary analysis of trial data

Facing an un-met need in lung cancer screening: The never smokers

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide and the second most common cancer in both men and women. In addition to smoking, other risk factors, such as environmental tobacco smoke, air pollution, biomass combustion, radon gas, occupational exposure, lung disease, family history of cancer, geographic variability, and genetic factors, play an essential role in developing LC. Current screening guidelines and eligibility criteria have limited efficacy in identifying LC cases (50 %), as most screening programs primarily target subjects with a smoking history as the leading risk factor. Implementing LC screening programs in people who have never smoked (PNS) can significantly impact cancer-specific survival and early disease detection. However, the available evidence regarding the feasibility and effectiveness of such programs is limited. Therefore, further research on LC screening in PNS is warranted to determine the necessary techniques for accurately identifying individuals who should be included in screening programs.

Race, age at diagnosis and histological characteristics of lung cancer in never-smokers (LCINS) and ever-smokers in low-dose computed tomography (LDCT) screening: a systematic review and meta-analysis

Background

We previously demonstrated in a meta-analysis there was no difference in risk ratio (RR) of lung cancer detected by low-dose computed tomography (LDCT) screening among female never-smokers (NS) and male ever-smokers (ES) in Asia. LDCT screening significantly decreased lung cancer death among Asian NS compared to Asian ES (RR =0.27, P<0.001).

Methods

We investigated if race, age at diagnosis, and histology further differentiate lung cancer diagnosed by LDCT among in NS and ES using the 14 studies from our previous meta-analysis.

Results

Twelve publications reported relevant data utilized in this study. From five Asian and one international studies, Asian ES had similar risk of lung cancer diagnosed at baseline screening as Asian NS [RR =0.96; 95% confidence interval (CI): 0.74-1.24] but among non-Asian ES had a 4.56 times significantly higher risk than non-Asian NS (RR =4.56; 95% CI: 2.85-7.28). The baseline incidence of lung cancer in never-smoker (LCINS) was approximately 2.3 times higher among Asian NS than non-Asian NS (0.62% vs. 0.27%, P=0.001). Asian ES had about half the baseline incidence of lung cancer diagnosed as non-Asian ES (0.65% vs. 1.26%). LCINS was diagnosed at 1.98 years younger than ES (95% CI: -3.38 to -0.58) (four studies) and exhibited a higher proportion of adenocarcinoma (ADC) (96.58% vs. 70.37%).

Conclusions

Among normal-risk individuals, LCINS had a significantly higher likelihood of being diagnosed among Asians than non-Asians, predominantly manifesting as ADC and diagnosed approximately 2 years younger than ES suggesting that the age limit to initiate lung cancer screening in NS may be set lower compared to LDCT lung cancer screening among ES.

Low-Dose Computed Tomography (LDCT) Lung Cancer Screening in Asian Female Never-Smokers Is as Efficacious in Detecting Lung Cancer as in Asian Male Ever-Smokers: A Systematic Review and Meta-Analysis

INTRODUCTION

Lung cancer in never-smokers is the major cancer cause of death globally. We compared the efficacy of low-dose computed tomography (LDCT) lung cancer screening among never-smokers versus ever-smokers using systematic review and meta-analysis.

METHODS

LDCT lung cancer screening studies that simultaneously included both ever-smoker and never-smoker participants published by April 30, 2021, were searched through PubMed and Scopus. Primary outcome measure was relative risk (RR) of lung cancer diagnosed among never-smokers versus ever-smokers.

RESULTS

A total of 14 studies (13 from Asia) were included (141,396 ever-smokers, 109,251 never-smokers, 1961 lung cancer cases diagnosed). RR of lung cancer diagnosed between ever-smokers versus never-smokers overall was 1.21 (95% confidence interval [CI]: 0.89-1.65), 1.37 (95% CI: 1.08-1.75) among males, and 0.88 (95% CI: 0.59-1.31) among females. RR was 1.78 (95% CI: 1.41-2.24) and 1.22 (95% CI: 0.89-1.68) for Asian female never-smokers versus male never-smokers and versus male ever-smokers, respectively, and 0.99 (95% CI: 0.65-1.50) versus high-risk ever-smokers (≥30 pack-years). Proportional meta-analysis revealed significantly more lung cancers diagnosed at first scan (95.4% [95% CI: 84.9-100.0] versus 70.9% [95% CI: 54.6-84.9], p = 0.010) and at stage 1 (88.5% [95% CI: 79.3-95.4] versus 79.7% [95% CI: 71.1-87.4], p = 0.071) among never-smokers versus ever-smokers, respectively. RR of lung cancer death and 5-year all-cause mortality in never-smokers versus ever-smokers was 0.27 (95% CI: 0.1-0.55, p < 0.001) and 0.13 (95% CI: 0.05-0.33, p < 0.001), respectively.

CONCLUSIONS

The RR of lung cancer detected by LDCT screening among female never-smokers and male ever-smokers in Asia was statistically similar. Overall and lung cancer specific mortality from the lung cancer diagnosed from LDCT screening was significantly reduced among never-smokers compared to ever-smokers.

The Introduction of Low-Dose CT Imaging and Lung Cancer Overdiagnosis in Chinese Women

BACKGROUND

Overdiagnosis of lung cancer by low-dose CT (LDCT) screening has raised concerns globally. LDCT screening has been used widely in employee health examinations in China since 2011.

RESEARCH QUESTION

Has the increasing use of LDCT in low-risk populations in China led to lung cancer overdiagnosis?

STUDY DESIGN AND METHODS

A total of 34,152 incident cases of and 27,208 deaths resulting from lung cancer in a population of approximately 3 million were derived from the Cancer Surveillance of Shanghai between 2002 and 2017. Changes in stage-specific and histologic type-specific incidence and mortality and incidence rate ratio (IRR) relative to the base year 2002 or to the period 2002 through 2005 were calculated by sex and were used to evaluate potential overdiagnosisve of lung cancer.

RESULTS

In men, both age-adjusted incidence of and mortality as a result of lung cancer decreased significantly up to 2008 and thereafter remained stable; in women, the incidence increased rapidly from 2011 (annual percentage change, 11.98%; 95% CI, 9.57%-14.45%), whereas the mortality declined persistently. The upward trend of incidence mainly was observed in lung adenocarcinoma in both sexes, with a sharper increase from 2012 through 2017. In men, the incidence of early-stage cancer increased 6.9 per 100,000 (95% CI, 5.1-8.7 per 100,000) and was accompanied by 5.5 per 100,000 (95% CI, -9.2 to -1.7 per 100,000) decline in late-stagecancer from 2002 through 2017. In women, early-stage incidence rose 16.1 per 100,000 (95% CI, 14.0-18.3 per 100,000), but no significant decline in late-stage cancer was found (absolute difference, -0.6 per 100,000; 95% CI, -2.8 to 1.7 per 100,000). The IRR was highest in most recent period and increased most in young women, mainly for early-stage cancer or lung adenocarcinoma.

INTERPRETATION

The results provide evidence at a population level for lung cancer overdiagnosis in Chinese women resulting from increasing LDCT screening in the low-risk populations. Criteria for LDCT screening and management of screening-detected nodules need to be addressed fully for expanded application of LDCT screening in China.

Lung cancer screening with low-dose computed tomography: National expenditures and cost-effectiveness

Objective

To compare the cost-effectiveness of undertaking low-dose computed tomography (LDCT) screening for early detection of lung cancer (LC) with different frequencies within the healthcare system of China, and estimate the additional national healthcare expenditure and five-year LC mortality associated with different screening frequencies.

Material and methods

A Markov model was established using national LC epidemiological data from the Chinese Center for Disease Control and Prevention, demographic data from the Chinese Statistical Yearbook, and cost and effectiveness data mainly from the Cancer Screening Program in China. The model included thirty sex-specific screening strategies, which were classified by initial screening age (30, 35, 40, 45, and 50), and screening intervals (intervals at single time point, 1, 2, 5, 10, and 20 years). The main model outputs were incremental cost-effectiveness ratios (ICERs), additional national healthcare expenditure and five-year LC mortality.

Results

The ICERs for LDCT screening strategies vs. non-screening strategy ranged from $16,086 per quality-adjusted life-year (QALY) to $3,675,491 per QALY in the male cohort, and from $36,624 per QALY to $5,943,556 per QALY in the female cohort. The annual increment national healthcare expenditures related to LDCT screening were varied from $0.25 to $13.39 billion, with the lower cost in the cohort with older screening ages and lower screening frequencies. More frequent screening with LDCT was associated with a greater reduction in LC death: an annual LDCT screening was linked to an estimated reduction in five-year LC death by 27.27-29.07%, while a one-off screening was linked to a reduction by 5.56-5.83%.

Conclusion

Under a willingness-to-pay (WTP) threshold of three times the Chinese gross domestic product (GDP) per capita (US $37,654), annual screening with an initiating age at 50 was most cost-effective in both male and female cohorts. By taking into account both the national healthcare expenditures and the effect of LDCT screening, our study results support undertaking LDCT screening annually from 50 years old in general populations.

Community-based lung cancer screening by low-dose computed tomography in China: First round results and a meta-analysis

OBJECTIVE

To evaluate the efficiency of low-dose computed tomography (LDCT) screening for lung cancer in China by analyzing the baseline results of a community-based screening study accompanied with a meta-analysis.

METHODS

A first round of community-based lung cancer screening with LDCT was conducted in Tianjin, China, and a systematic literature search was performed to identify LDCT screening and registry-based clinical studies for lung cancer in China. Baseline results in the community-based screening study were described by participant risk level and the lung cancer detection rate was compared with the pooled rate among the screening studies. The percentage of patients per stage was compared between the community-based study and screening and clinical studies.

RESULTS

In the community-based study, 5523 participants (43.6% men) underwent LDCT. The lung cancer detection rate was 0.5% (high-risk, 1.2%; low-risk, 0.4%), with stage I disease present in 70.0% (high-risk, 50.0%; low-risk, 83.3%), and the adenocarcinoma present in 84.4% (high-risk, 61.5%; low-risk, 100%). Among all screen-detected lung cancer, women accounted for 8.3% and 66.7% in the high- and low-risk group, respectively. In the screening studies from mainland China, the lung cancer detection rate 0.6% (95 %CI: 0.3%-0.9%) for high-risk populations. The proportions with carcinoma in situ and stage I disease in the screening and clinical studies were 76.4% (95 %CI: 66.3%-85.3%) and 15.2% (95 %CI: 11.8%-18.9%), respectively.

CONCLUSIONS

The stage shift of lung cancer due to screening suggests a potential effectiveness of LDCT screening in China. Nearly 70% of screen-detected lung cancers in low-risk populations are identified in women.