The investigators propose a randomized controlled trial to evaluate the clinical effectiveness of low-dose computed tomography (LDCT) for lung cancer screening in high-risk Chinese ever-smokers aged 50-79 years in Hong Kong and to assess the cost-effectiveness of implementing LDCT for lung cancer screening in the local setting.
Background: Lung cancer is an important public health problem in Hong Kong and worldwide. In Hong Kong, lung cancer always ranked the top in terms of incidence and mortality among common cancers in both sexes. Previous studies has suggested that cancer screening could potentially achieve a stage shift that enables the diagnosis of more cancer cases in early-stages (I or II), thereby enabling earlier treatment of early-stage cancers rather than advanced-stage cancers to achieve higher survival rates and reduction in the overall mortality. In particular, low-dose computed tomography (LDCT) was reported to be effective in screening for lung cancer among smokers in some countries. However, given the vast difference in smoking prevalence, lung cancer incidence and staging pattern at presentation, findings regarding both benefits and harms from one population may not be directly applicable to other populations. This highlights the importance of local evidence on both clinical effectiveness and cost-effectiveness of LDCT lung cancer screening in Hong Kong. Aim: To implement LDCT screening for high-risk ever-smokers to generate local data and robust evidence on the clinical effectiveness, cost-effectiveness, and feasibility of LDCT screening. Study Design and overview: This study will adopt the design of a randomized controlled trial. A total of 15,000 high-risk Chinese ever-smokers, aged 50-79 years with a smoking history of at least 20 pack-years in Hong Kong will be recruited. We target both current smokers, and former smokers who had quitted within the past 10 years. All participants are targeted to be recruited in the first year of the study, and to be followed-up for a total of 10 years; including regular active follow-up in the initial five years followed by an interim analysis to be conducted by the end of that period, and continuous outcome ascertainment by data matching in the next five years before the final analysis. After the baseline recruitment visit (T0), all enrolled participants will be randomized with a 1:1 ratio into either the screening arm (n = 7,500) with 3 LDCT screening to be done during the study period, or the control arm (n = 7,500) with no screening provided. All participants will be followed-up at 18 ± 3 months (T1), 42 ± 3 months (T2), and at 60 months (T3) from baseline. The three rounds of LDCT screening for participants in the screening arm will be performed at T0, T1, and T2. Participants in both arms will have free blood tests at T0, T1, and T2, with complete blood count (CBC), lipid function, and basic renal and liver function test (RFT/LFT) to be tested at different designated time points. All participants, in both the screening or control arm will be referred to smoking cessation services provided by the participating non-government organizations (NGOs) upon randomization. Participants' consents for accessing their updated health status data from various sources will be obtained. Data on lung cancer incidence and mortality of participants will be continuously ascertained on follow-up contact. Cancer-related details including stage on diagnosis, laboratory test results, treatments including medication offered and procedures performed will be collected every 6 months through an agreement to be worked out with the Data Sharing Portal services of the Hospital Authority (HA), to be supplemented by clarification through HA's Clinical Management System (CMS) if needed. The survival status of participants will be continuously updated on follow-up contact, and to be checked though the Deaths Registry if needed, for up to 10 years since randomization on a half-yearly basis. Interventions: SCREEN arm: 3 LDCT screening services will be provided. CONTROL arm: No LDCT screening service will be provided. Study Endpoints and outcome measures: The primary endpoint of this study is lung cancer mortality. Secondary endpoints includes (i) stage distribution of lung cancer cases; (ii) lung cancer incidence; (iii) prevalence of false-positive of screening cases; (iv) percentage of overdiagnosis of lung cancer cases; (v) prevalence of radiation-induced cancers; and (vi) health-related quality of life (HRQoL). Main analysis: Intention-to-screen (ITS) approach. Potential significance: The findings will help to inform evidence-based recommendations for the consideration of lung cancer screening in Hong Kong's healthcare system.
3 rounds of LDCT screening performed at the baseline (T0), 18 ± 3 months (T1), 42 ± 3 months (T2) from baseline
School of Public Health, The University of Hong Kong
Hong Kong, Hong Kong
Lung cancer mortality
Defined as the lung cancer-related death. The survival status of diagnosed lung cancer patients in both arms will be reviewed yearly after the first five years up to 10 years through Hospital Authority of Hong Kong (HA)'s Data Sharing Portal services or the Deaths Registry, supplemented by access to Clinical Management System (CMS) if needed. The lung cancer mortality rate will be calculated by dividing (a) the number of lung cancer-related deaths by (b) the number of person-years.
Time frame: 10 years
Stage distribution of lung cancer cases
Defined as the stage distribution of lung cancer cases in both arms. The number of lung cancer cases of diagnosed cancer stages, namely, stages 1, 2, 3, and 4, as well as unstaged, will be recorded.
Time frame: 10 years
Lung cancer incidence
Long-term lung cancer-related data will be extracted through electronic medical record systems to evaluate the changes in lung cancer incidence rate in both arms. Data on lung cancer incidence related details and the survival status will be reviewed yearly up to 10 years through the Hospital Authority of Hong Kong (HA)'s Data Sharing Portal and the Deaths Registry, and to be supplemented by access to Clinical Management System (CMS) at HA for clarification and checking of specific issues if needed.
Time frame: 10 years
Prevalence of false-positive of screening cases
A false positive screen refers to a positive screen that no lung cancer is diagnosed after undergoing further confirmatory diagnostic workup. The prevalence of false-positive of screening cases is calculated as dividing (a) the number of false positive screenings by (b) the total number of scans performed.
Time frame: 10 years
Percentage of overdiagnosis of lung cancer cases
Overdiagnosis refers to a screen-detected lung cancer case that would not be diagnosed if screening is not performed. The overdiagnosis percentage in all diagnosed lung cancer cases in the screening arm is calculated as dividing (a) the difference between the rate of lung cancer detected in the screening arm and the control arm by (b) the rate of lung cancer detected in the screening arm.
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SCREENING
Masking
NONE
Enrollment
15,000
Time frame: 10 years
Prevalence of radiation-induced cancers
The potential impact of additional radiation exposure to the development of cancers at sites other than the lung among participants in the screening arm will be assessed.
Time frame: 10 years
Health-related quality of life (HRQoL)
A HRQoL assessment based on the EQ-5D instrument will be completed by all participants in both arms at the baseline (T0), 18 ± 3 months (T1), 42 ± 3 months (T2), and 60 months (T3) from baseline. The HRQoL score will be compared between participants in the screening arm and the control arm. The consideration of HRQoL enables quantifying the effects of early detection and early treatment on screen-detected cases in terms of the changes in survival time and health status.
Time frame: 10 years