Evaluation of lung Cancer Screening
Date Issued
2008
Date
2008
Author(s)
Chien, Chun-Ru
Abstract
Background & Objectives: Lung cancer is the leading cause of cancer death world wide. There is no effective screening modality so far, and screening computed tomography (CT) is highly debated. There were two large ongoing randomized trials comparing CT v.s. observation (the Dutch-Belgian randomised lung cancer screening trial (NELSON)) or chest xray (CXR)(national lung screening trial, NLST), with results awaiting. The aims of this study were to (1) estimate the baseline incidence of lung cancer by age, period, cohort, (2) to estimate the mean sojourn time ( MST) of lung cancer by different screening modality; (3) to develop a decision modeling for economic evaluation of lung cancer screening by different intervals and screening modalities based on (1) and (2).ethods: We build up a five state Markov model to simulate the effectiveness (mainly presented as incremental life expectancy, ILE) and cost-utility analysis (presented as incremental cost-utility (in terms of quality-adjusted life year, QALY) ratio, ICUR) of lung cancer screening. Important parameters (incidence, mean sojourn time (MST), and treatment compliance) were established separately in order to implement the model. As to incidence, lung cancer cases (n=44139) diagnosed between 1996 and 2002 in Taiwan were analyzed by using a Bayesian age-period-cohort (BAPC) model. Age-adjusted standardized incidence rate (ASIR, per 100000 person-year) were calculated. As to MST by CT, data from six prospective CT screening studies were retrieved based on systematic literature review. The MST in association with the natural history of lung cancer depicted by a three-state Markov model was estimated with a Bayesian approach. As to MST by CXR, we collected data on demographic features, histology type, survival status, history of smoking, and asymptomatic or symptomatic status in light of chief complaint at diagnosis retrieved from medical records based on institutional cancer registry for lung cancer patients with prior non-diagnostic CXR (n=221) as an opportunistic screening cohort. The MST for the natural history of lung cancer underpinning a three-state Markov model was estimated with a Bayesian approach. As to treatment compliance, it was estimated from hospital cancer registry (from year 1991 to 2002, n=4565) via descriptive analysis. Other complimentary parameters were cited based on western literatures. Model validation was based on comparison between estimates and reported literatures for stage specific case identification, stage specific survival, and stage specific treatment related cost. Finally, effectiveness and cost-utility analysis of lung cancer screening were estimated via the above mentioned model and parameters for our primary and complementary scenarios. The primary scenario was a NELSON like (for selected smoker with median age 61 y/o) setting. esults: The prediction of our BAPC model was close to observation, and showed slightly decreasing incidence after around year 2000 for male but still slightly increasing for female. The median (95%CI) estimated annual incidence rate (/100000) of lung cancer in 61 year-old Taiwanese would be 102 (80~127) for male and 31 (22~44) for female in year 1996. The corresponding figures in year 2002 would be 123 (99~147) and 58 (45~75) respectively. The median (95% confidence interval, 95%CI) MST of lung cancer with screening CT was estimated as 2.06 (0.42~3.83) years. The median (95%CI) MST by screening CXR was estimated as 5.51 (4.04~7.12) months. Small cell lung carcinoma was even statistically significantly shorter MST than non-small cell lung carcinoma (3.01 months (3-3.98) versus 6.07 (4.44-8.25) months). The treatment compliance rates were 40% for advanced stage diseases. Model validation revealed comparable results in case finding (estimated/reported cases: 1.1%/1.3% for early stage disease and 1.4%/1.5% for all lung cancer), stage-specific survival (estimated/reported 5-year survival: (0.62~0.77)/(0.54~0.73) for early stage disease and (0~0.01)/(0.01~0.07) for advanced disease), and treatment related cost (US dollars, USD)(estimated/reported: 25183/25050 for early stage and 22372/20691 for advanced stage disease). In NELSON like setting, the median (95%CI) ILE would be 0.018 (-0.04~0.07) year. The mean ICUR (USD/QALY) would be 125171 in societal point of view (237145 if in payer’s point of view). In consider of the impact of different screening schedules, annual CT screening is associated with less lung cancer death when compared with three-yearly screening (percentage of lung cancer death: 2.1% vs 2.4%), but it is not cost-benefit when utility and cost was taken into account. In consider of different screening modality, CT screening vs CXR screening is more cost-benefit when compared with our main scenario (mean ICUR: 89348). If screening program was performed in a country with low incidence rate such as Taiwan (incidence of lung cancer for smoker in the NELSON like setting being 0.00171~ 0.00185 in year 2002), the median ILE would be 0.0067~0.0071 year. The mean ICUR (USD/QALY) would be 447258~752571.onclusion: (1) Lung cancer incidence in Taiwan was slightly decreasing for male but slightly increasing for female. (2) The shorter mean sojourn time by using CXR as compared with MST by CT strongly suggests that CT screening may be more effective in early detection of lung cancer in screening. (3) Health economic evaluation based on (1) & (2) revealed that lung cancer screening with CT may lead to an increase in life expectancy and reduce lung cancer mortality, but the incremental cost-utility ratio remained high when compared with other cancer screening.
Subjects
lung cancer
screening
computed tomography
incidence
mean sojourn time
pattern of care
effectiveness
cost-utility analysis
SDGs
Type
thesis
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