Lung cancer screening using low-dose CT: The current national landscape

Objectives

Although the National Lung Screening Trial (NLST) lauds the efficacy of low-dose computed tomography (LDCT) at reducing lung cancer mortality, it has not been widely used for population-based screening. By examining the availability of U.S. LDCT screening centers, and underlying rates of lung cancer incidence, mortality, and smoking prevalence, the need for additional centers may be determined.

Materials and methods

Locations of 203 LDCT screening centers from the Lung Cancer Alliance Screening Centers of Excellence database, a list of active NLST and International Early Lung and Cardiac Action Program (I-ELCAP) screening centers, and an independently conducted survey of Society of Thoracic Radiology members were geocoded and mapped. County-level rates of lung cancer incidence, mortality, and smoking prevalence were also mapped and overlaid with the locations of the 203 LDCT screening centers.

Results and conclusions

Results showed the majority of LDCT screening centers were located in the counties with the highest quartiles of lung cancer incidence and mortality in the Northeast and East North Central states, but several high-risk states had no or few identified screening centers including Oklahoma, Nevada, Mississippi, and Arkansas. As guidelines are implemented and reimbursement for LDCT screening follows, equitable access to LDCT screening centers will become increasingly important, particularly in regions with high rates of lung cancer incidence and smoking prevalence.     

Tobacco use in adult long-term survivors of retinoblastoma.

A significant risk of lung cancer was identified among hereditary, but not nonhereditary, retinoblastoma (Rb) patients. Tobacco use was investigated to determine whether differences in smoking prevalence might explain the lung cancer excess and to characterize smoking patterns in adult survivors of Rb. Subjects were 441 hereditary and 395 nonhereditary 1-year survivors of Rb, age >or=18 years, who responded to a telephone survey about current health behavior, including tobacco use. Response rates were 76% for hereditary and 73% for nonhereditary survivors. We compared patterns and predictors of current tobacco use among hereditary and nonhereditary survivors with other childhood cancer survivor studies and the U.S. population. Hereditary Rb survivors currently smoke cigarettes significantly less frequently than nonhereditary survivors (16. 8% versus 24.3%), although among current smokers, age at smoking initiation (17 years old) and average cigarettes (1.5 packs) smoked daily are similar. Predictors of current and ever cigarette smoking include nonhereditary Rb, older age, being female, less education, and use of other tobacco products. Rb survivors smoke cigarettes significantly less than the U.S. population (rate ratio, 0.63; 95% confidence interval, 0.5-0.8 for males; rate ratio, 0.75; 95% confidence interval, 0.6-0.9 for females), but Rb survivors have comparable smoking rates with other childhood cancer survivors. Smoking did not account for the increased risk of lung cancer among hereditary Rb patients, and this may point to an enhanced sensitivity to the carcinogenic effects of tobacco. Adult survivors of Rb should be encouraged to stop smoking.     

Estimating the Cost-Effectiveness of Lung Cancer Screening with Low-Dose Computed Tomography for High-Risk Smokers in Australia

Introduction

Health economic evaluations of lung cancer screening with low-dose computed tomography (LDCT) that are underpinned by clinical outcomes are relatively few.

Lung cancer rates convergence in young men and women in the United States: analysis by birth cohort and histologic type

Age-specific rates of lung cancer have been consistently higher for men than for women in the United States, due primarily to different patterns of cigarette smoking. Gender differences in cigarette smoking have diminished in recent birth cohorts, however, especially among whites. We used U.S. population-based incidence and mortality data and examined trends in age-specific rates of lung cancer by birth cohort according to gender, ethnic group, and histology to evaluate the generational changes in U.S. lung cancer risk for men vs. women. All tests of statistical significance are 2-sided (95% confidence interval [CI]). Lung cancer mortality rates have converged between men and women born after 1960, especially in whites. The male-to-female (M:F) mortality rate ratio for ages 35-39 years decreased from 3.0 (95% CI = 2.7-3.4) around the 1915 birth cohort to 1.1 (95% CI = 1.0-1.1) around the 1960 birth cohort among whites and from 4.0 (95% CI = 3.2-5.0) around the 1925 birth cohort to 1.5 (95% CI = 1.3-1.7) around the 1960 birth cohort among blacks. Similarly, incidence rates for white men and women converged rapidly for adenocarcinoma, small cell carcinoma, and large cell carcinoma, but less so for squamous cell carcinoma. These findings reflect the smoking patterns among white and black men and women: cigarette smoking prevalence at age 24 was essentially equal among white men and women born after 1960 but continued to be higher in black men than women. The convergence of lung cancer death rates among men and women born after 1960s supports the idea that males and females maybe equally susceptible to develop lung cancer from a given amount of cigarette smoking, rather than the hypothesis that women are more susceptible.     

Changes in the smoking habits of adults in the United States and recent trends in lung cancer mortality

Recent shifts in lung cancer mortality in the United States are believed to be related to changing patterns of cigarette smoking among adults. From 1960-1977 the age-adjusted mortality rate for lung cancer increased by 85%. Increases in lung cancer mortality rates were much greater among females than males. The recent rapid increase in female lung cancer mortality appears to be the result of higher rates of cigarette smoking among women born between 1920 and 1940 compared to earlier generations. These women, who are now in their 40's, 50's, and 60's are now beginning to reach an age where lung cancer rates will be adversely affected. In contrast, peak smoking prevalence rates occurred among men who are now in their 60's and 70's. The proportion of men who smoke cigarettes has been declining steadily with successive generations born after 1930. Findings from this analysis suggest that recent shifts in lung cancer mortality in the United States can be largely explained by examining changes in the smoking habits of adults.     

血清自身抗体联合低剂量螺旋CT在肺癌早期筛查中的价值

目的 探讨血清自身抗体检测联合低剂量螺旋CT（LDCT）在肺癌早期筛查中的可行性。方法 收集武汉大学人民医院体检中心体检人群12 568例体检资料,男7 453例、女5 115例,筛选出肺癌高危人群1 324例纳入本研究,该人群均进行胸部X线检查。随机选取443例患者采用低剂量螺旋CT检测;488例患者采用血清自身抗体进行检测;393例患者采用血清自身抗体联合低剂量螺旋CT检测。均随访一年,比较不同筛查方法对肺结节初筛阳性率及肺癌确诊率,早期肺癌筛查的敏感度及特异性。结果 血清自身抗体联合低剂量螺旋CT检测对于发现肺结节的初筛率、肺癌的确诊率及不同直径肺结节的检出率均明显高于低剂量螺旋CT组及血清自身抗体检测组（P<0.001）。血清自身抗体联合低剂量螺旋CT检测的特异性为89.1%,敏感度为88.4%,AUC为0.863。结论 血清自身抗体检测联合低剂量螺旋CT可明显提高高危人群早期肺癌筛查的确诊率,为寻找肺癌筛查路径提供理论依据。     

Cigarette Smoking Among Lesbians, Gays, and Bisexuals: How Serious a Problem? (United States)

INTRODUCTION: Population-based health surveys seldom assess sexual orientation, which results in the absence of a reliable measure of smoking among lesbians, gays, and bisexuals (LGB), a population perceived to have higher risks of tobacco-related diseases. This is the first study to compare the cigarette smoking rate of LGB with that of heterosexual individuals using a population-based sample with both male and female adults, and to identify which sub segments of LGB population are particularly burdened by tobacco use. METHODS: California Health Interview Survey (CHIS), a population-based telephone survey was used to assess smoking prevalence and its correlates among respondents. Of 44,606 respondents, 343 self-identified as lesbian; 593 self-identified as gay; and 793 identified themselves as bisexual (511 female and 282 male). Statistical analysis was performed using SAS and SUDAAN. RESULTS: Lesbians' smoking rate (25.3%), was about 70% higher than that of heterosexual women (14.9%) Gay men had a smoking prevalence of 33.2%, comparing to heterosexual men (21.3%). After controlling for demographic variables, logistic regression analysis showed that lesbians and bisexual women were significantly more likely to smoke compared with heterosexual women (OR = 1.95 and OR = 2.08, respectively). Gay men were also significantly more likely to smoke than heterosexual men (OR = 2.13; 95% CI = 1.66-2.73). Being 35-44-years-old, non-Hispanic White, and having low-education attainment and low-household income were common demographic predictors of cigarette smoking among LGB. CONCLUSION: Our study provides the strongest evidence to date that lesbians, bisexual females, and gay men had significantly higher cigarette smoking prevalence rates than their heterosexual counterparts.     

Potential Impact of Criteria Modifications on Race and Sex Disparities in Eligibility for Lung Cancer Screening

IntroductionLow-dose computed tomography (LDCT) screening reduces lung cancer mortality, but current eligibility criteria underestimate risk in women and racial minorities. We evaluated the impact of screening criteria modifications on LDCT eligibility and lung cancer detection.MethodsUsing data from a Lung Nodule Program, we compared persons eligible for LDCT by the following: U.S. Preventive Services Task Force (USPSTF) 2013 criteria (55–80 y, ≥30 pack-years of smoking, and ≤15 y since cessation); USPSTF2021 criteria (50–80 y, ≥20 pack-years of smoking, and ≤15 y since cessation); quit duration expanded to less than or equal to 25 years (USPSTF2021-QD25); reducing the pack-years of smoking to more than or equal to 10 years (USPSTF2021-PY10); and both (USPSTF2021-QD25-PY10). We compare across groups using the chi-square test or analysis of variance.ResultsThe 17,421 individuals analyzed were of 56% female sex, 69% white, 28% black; 13% met USPSTF2013 criteria; 17% USPSTF2021; 18% USPSTF2021-QD25; 19% USPSTF2021-PY10; and 21% USPSTF2021-QD25-PY10. Additional eligible individuals by USPSTF2021 (n = 682) and USPSTF2021-QD25-PY10 (n = 1402) were 27% and 29% black, both significantly higher than USPSTF2013 (17%, p < 0.0001). These additional eligible individuals were 55% (USPSTF2021) and 55% (USPSTF2021-QD25-PY10) of female sex, compared with 48% by USPSTF2013 (p < 0.05). Of 1243 persons (7.1%) with lung cancer, 22% were screening eligible by USPSTF13. USPSTF2021-QD25-PY10 increased the total number of persons with lung cancer by 37%. These additional individuals with lung cancer were of 57% female sex (versus 48% with USPSTF2013, p = 0.0476) and 24% black (versus 20% with USPSTF2013, p = 0.3367).ConclusionsExpansion of LDCT screening eligibility criteria to allow longer quit duration and fewer pack-years of exposure enriches the screening-eligible population for women and black persons.     

Role of Low-Dose Computerized Tomography in Lung Cancer Screening among Never-Smokers

Introduction

The incidence of lung cancer among never-smokers has been increasing rapidly. The U. S. National Lung Screening Trial and the NELSON trial showed that screening using low-dose computerized tomography (LDCT) effectively reduced lung cancer mortality among heavy smokers. However, its effectiveness in never-smokers has not been well investigated. This study investigated the role of LDCT in lung cancer screening among never-smokers.

Evaluation of Promotional Materials To Promote Low-Dose Computed Tomography (LDCT) Screening to High-Risk Consumers and Health Care Providers

Low-dose computed tomography (LDCT) screening is a promising screening modality for increasing the detection rate of early stage lung cancers among high-risk individuals. Despite being recommended by the US Preventative Services Task Force, uptake of LDCT remains low. The objective of the current study was to gather feedback from high-risk consumers and health care providers on LDCT promotional materials. Focus group discussions were conducted with high-risk individuals (8 focus groups; N = 38) and primary care providers (9 focus groups; N = 23). Participants reviewed existing LDCT promotional materials to assess their perceptions of media materials created to publicize LDCT. Data were analyzed using the constant comparative method. Several key themes emerged from focus groups that can be used to inform development of future LDCT promotional materials. High-risk (HR) participants expressed greater receptivity for promotional materials that did not further stigmatize lung cancer and/or smoking and expressed preferences for materials that clearly outlined the risks/benefits of screening. Primary care providers (PCPs) offered suggestions to facilitate the referral process such as diagnostic codes and requested a design that clearly outlined eligibility criteria. A clear and thorough explanation of LDCT eligibility, cost, harms, and benefits was of chief importance for both PCP and HR audiences. Given that PCPs and HR audiences are not well informed on the specifics of LDCT screening eligibility and insurance coverage, creating provider and patient education opportunities will aid in shared decision-making opportunities. Promotional materials that meet the needs of the target audience are needed to facilitate discussions of risks/benefits of screening with HR individuals.     

Lung cancer screening with low-dose computed tomography: costs, national expenditures, and cost-effectiveness

A recent randomized trial showed that low-dose CT (LDCT) screening reduces lung cancer mortality. Health care providers need an assessment of the national budget impact and cost-effectiveness of LDCT screening before this intervention is adopted in practice. Using data from the 2009 National Health Interview Survey, CMS, and the National Lung Screening Trial (NLST), the authors performed an economic analysis of LDCT screening that includes a budget impact model, an estimate of additional costs per lung cancer death avoided attributed to screening, and a literature search of cost-effectiveness analyses of LDCT screening. They conducted a one-way sensitivity analysis, reporting expenditures in 2011 U.S. dollars, and took the health care payer and patient perspectives. LDCT screening will add $1.3 to $2.0 billion in annual national health care expenditures for screening uptake rates of 50% to 75%, respectively. However, LDCT screening will avoid up to 8100 premature lung cancer deaths at a 75% screening rate. The prevalence of smokers who qualify for screening, screening uptake rates, and cost of LDCT scan were the most influential parameters on health care expenditures. The additional cost of screening to avoid one lung cancer death is $240,000. Previous cost-effectiveness analyses have not conclusively shown that LDCT is cost-effective. LDCT screening may add substantially to the national health care expenditures. Although LDCT screening can avoid more than 8000 lung cancer deaths per year, a cost-effectiveness analysis of the NLST will be critical to determine the value of this intervention and to guide decisions about its adoption.     

Incidence and etiology of lung cancer in the Pacific Basin

Incidence of lung cancer in the Pacific Basin was either compiled from published reports or computed by the authors. The results showed a great variation in age-standardized annual incidence rates of lung cancer among 10 countries and 17 areas in the Pacific Basin where tumor registry statistics are available. For males the incidence rates ranged from 10 to over 70 and for females from less than 5 to over 30/100,000 population. The reason(s) for the great variation is unclear. Ionizing radiation, carcinogenic chemical substances (e.g., chromium, arsenic compounds, asbestos, etc.), or air pollution are unlikely to be responsible. Because cigarette smoking is known to be a major cause of lung cancer, the authors have suggested that surveys on cigarette smoking be conducted among various populations in the Pacific Basin so that etiologic significance of cigarette smoking for the noted variation can be assessed. In Hawaii such a survey is underway, and a preliminary analysis was made to examine the association between lung cancer and cigarette smoking among five races.     

An examination of sexual orientation group patterns in mammographic and colorectal screening in a cohort of U.S. women

Purpose

Underutilization of cancer screening has been found especially to affect socially marginalized groups. We investigated sexual orientation group patterns in breast and colorectal cancer screening adherence.

Methods

Data on breast and colorectal cancer screening, sexual orientation, and sociodemographics were gathered prospectively from 1989 through 2005 from 85,759 U.S. women in the Nurses’ Health Study II. Publicly available data on state-level healthcare quality and sexual-orientation-related legal protections were also gathered. Multivariable models were used to estimate sexual orientation group differences in breast and colorectal cancer screening, controlling for sociodemographics and state-level healthcare quality and legal protections for sexual minorities.

Results

Receipt of a mammogram in the past 2 years was common though not universal and differed only slightly by sexual orientation: heterosexual 84 %, bisexual 79 %, and lesbian 82 %. Fewer than half of eligible women had ever received a colonoscopy or sigmoidoscopy, and rates did not differ by sexual orientation: heterosexual 39 %, bisexual 39 %, and lesbian 42 %. In fully adjusted models, state-level healthcare quality score, though not state-level legal protections for sexual minorities, was positively associated with likelihood of being screened for all women regardless of sexual orientation.

Conclusions

Concerns have been raised that unequal healthcare access for sexual orientation minorities may adversely affect cancer screening. We found small disparities in mammography and none in colorectal screening, though adherence to colorectal screening recommendations was uniformly very low. Interventions are needed to increase screening in women of all sexual orientation groups, particularly in areas with poor healthcare policies.     

Annual number of lung cancer deaths potentially avertable by screening in the United States

BACKGROUND:

The National Lung Screening Trial (NLST), which was conducted between 2002 and 2009, demonstrated that screening with low‐dose computed tomography (LDCT) reduced lung cancer mortality by 20% among screening‐eligible populations compared with chest x‐ray. In this article, the authors provide an estimate of the annual number of lung cancer deaths that can be averted by screening, assuming the screening regimens adopted in the NLST are fully implemented in the United States.

METHODS:

The annual number of lung cancer deaths that can be averted by screening was estimated as a product of the screening effect, the US population size (obtained from the 2010 US Census data), the prevalence of screening eligibility (estimated using the 2010 National Health Interview Survey [NHIS] data), and the lung cancer mortality rates among screening‐eligible populations (estimated using the NHIS data from 2000‐2004 and the third National Health and Nutrition Examination Survey linked mortality files). Analyses were performed separately by sex, age, and smoking status, with Poisson regression analysis used for mortality rate estimation. Uncertainty of the estimates of the number of avertable lung cancer deaths was quantified by simulation.

RESULTS:

Approximately 8.6 million Americans (95% confidence interval [95% CI], 8.0 million‐9.2 million), including 5.2 million men (95% CI, 4.8 million‐5.7 million) and 3.4 million women (95% CI, 3.0 million ‐3.8 million), were eligible for lung cancer screening in 2010. If the screening regimen adopted in the NLST was fully implemented among these screening‐eligible US populations, a total of 12,250 (95% CI, 10,170‐15,671) lung cancer deaths (8990 deaths in men and 3260 deaths in women) would be averted each year.

CONCLUSIONS:

The data from the current study indicate that LDCT screening could potentially avert approximately 12,000 lung cancer deaths per year in the United States. Further studies are needed to estimate the number of avertable lung cancer deaths and the cost‐effectiveness of LDCT screening under different scenarios of risk, various screening frequencies, and various screening uptake rates. (See editorial on pages 000–000, this issue.) Cancer 2013. © 2012 American Cancer Society.     

Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002)

OBJECTIVE: To evaluate the feasibility of using low-dose computed tomography (LDCT) for the early diagnosis of lung cancer and malignant pleural mesothelioma in an asbestos-exposed population. METHODS: Between February 2002 and October 2003, 1,045 volunteers already enrolled in a surveillance program for asbestos-exposed workers and former workers were recruited. The main eligibility criteria were: written informed consent, definite exposure to asbestos, age 40-75, no prior cancer or severe concomitant conditions, no chest CT scan in the past 2 years. A smoking history was not required. After a structured interview, chest X-ray (CXR) and LDCT were performed. Participants with negative examinations were assigned to annual LDCT. Participants with positive findings received high-resolution CT and additional diagnostic workup as appropriate. RESULTS: Baseline characteristics of the screened population were: median asbestos exposure time, 30 years; median age, 58; median pack-years in smokers/former smokers, 18.5. Thirty-four percent had never smoked. On LDCT, 834 noncalcified nodules were identified in 44% of participants, versus 43 nodules in 4% on CXR. Pleural abnormalities were observed in 44% and 70% of participants by CXR and LDCT, respectively. Overall, LDCT identified nine cases of non-small cell lung cancer-eight stage I, one stage IIA-and one thymic carcinoid, corresponding to 1% of the enrolled population. All cases were radically treated. None had been detected by CXR. No pleural mesothelioma was diagnosed. There were 11 false-positive results. CONCLUSIONS: Our findings first suggest that LDCT may be at least as useful in asbestos workers as in heavy smokers for the early diagnosis of lung cancer; this benefit is evident even in a poor-risk population, with low rates of smoking prevalence and a previous history of radiological surveillance. The role of spiral tomography in screening for pleural mesothelioma remains uncertain.     

Risk factors for lung cancer in Singapore Chinese, a population with high female incidence rates

The high incidence of lung cancer in Chinese females in Singapore, especially among those belonging to the Cantonese dialect group, and the relatively high rates in Chinese males have been studied by means of interviews of cases and controls. A significant dose-response effect of cigarette smoking was found for all male and female groups, but neither smoking nor any other exposure explains the high incidence of lung cancer observed in Cantonese females who exhibit high rates of adenocarcinoma appraently unrelated to smoking. In general, persons with a low consumption of green vegetables were at higher risk for lung cancer. This finding might be due to an increased susceptibility in the presence of a relative deficiency of vitamin A.     

Mortality Trends for Lung Cancer and Smoking Prevalence In Peru

Objectives: Lung cancer continues to be  the leading cause of cancer-related deathworldwide. Have been reported high mortality rates from lung cancer in Latin America, but the disparities within the regions of Peru and under-reporting death certification reported prevent the inclusion of Peru in analysis of the mortality trends for lung cancer. We evaluated lung cancer mortality trends and smoking prevalence in Peru and its geographical areas. Materials and Methods: We obtained the data from the registry of the Peruvian Ministry of Health between 2008 and 2017. Mortality rates per 100,000 person-years were computed using the world’s SEGI population and trends were analyzed using the Joinpoint regression Program Version 4.7.0. Smoking prevalence was estimated from the Demographic and Family Health Survey. Results: In Peru, mortality rates were roughly 1.3 times higher in males than in females. The coast region had significant downward trends among males, whereas the highlands region had significant upward trends among females. According to provinces, Apurimac showed an annually significant rise in both sexes (+10.6% in males, and +11.6% in females). In general, smoking prevalence was higher in males compared to females, principally among young adults.   Conclusions: Peru showed downward mortality trends in the last decade with variability across regions. Males had a higher smoking prevalence, principally among young adults. Public health interventions for smoking reduction should be implemented to reduce lung cancer mortality.     

The impact of overdiagnosis on the selection of efficient lung cancer screening strategies

The U.S. Preventive Services Task Force (USPSTF) recently updated their national lung screening guidelines and recommended low‐dose computed tomography (LDCT) for lung cancer (LC) screening through age 80. However, the risk of overdiagnosis among older populations is a concern. Using four comparative models from the Cancer Intervention and Surveillance Modeling Network, we evaluate the overdiagnosis of the screening program recommended by USPSTF in the U.S. 1950 birth cohort. We estimate the number of LC deaths averted by screening (D) per overdiagnosed case (O), yielding the ratio D/O, to quantify the trade‐off between the harms and benefits of LDCT. We analyze 576 hypothetical screening strategies that vary by age, smoking, and screening frequency and evaluate efficient screening strategies that maximize the D/O ratio and other metrics including D and life‐years gained (LYG) per overdiagnosed case. The estimated D/O ratio for the USPSTF screening program is 2.85 (model range: 1.5–4.5) in the 1950 birth cohort, implying LDCT can prevent ～3 LC deaths per overdiagnosed case. This D/O ratio increases by 22% when the program stops screening at an earlier age 75 instead of 80. Efficiency frontier analysis shows that while the most efficient screening strategies that maximize the mortality reduction (D) irrespective of overdiagnosis screen through age 80, screening strategies that stop at age 75 versus 80 produce greater efficiency in increasing life‐years gained per overdiagnosed case. Given the risk of overdiagnosis with LC screening, the stopping age of screening merits further consideration when balancing benefits and harms.     

Lung cancer

The number of lung cancer deaths in Japan has been continuously increasing for decades, mainly because of the growing size of the elderly population. In contrast, age-specific lung cancer death rates for those aged under 79 years plateaued recently, reflecting the decreasing smoking rates since 1966. However, the smoking rate for males (54% in 1999) is still extraordinarily high in Japan compared to other developed countries, so it is necessary to further promote anti-smoking activities. It is reported that the relative risk for lung cancer due to cigarette smoking increases 4-5 fold (current smokers versus non-smokers) for males and 2-3 fold for females, and that the population attributable risk is 70% for males and 15-25% for females in Japan, which indicates that cigarette smoking is the most influential risk factor for lung cancer. However, the magnitude of the relative risk and population attributable risk is not as high as those observed in other developed countries. In order to clarify the reasons for this, it is necessary to further accumulate findings from actual epidemiological studies in Japan. In addition to cigarette smoking, occupational exposures, dietary habits (low intake of vegetables and fruits), atmospheric air pollution, environmental tobacco smoke, cooking and heating fuels, indoor radon and previous lung diseases are reported to increase the risk of lung cancer.     

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

IntroductionLung 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.MethodsLDCT 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.ResultsA 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.ConclusionsThe 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.