Lung Cancer Screening: Optimization through risk stratification

Lung cancer is the leading cause of cancer related mortality worldwide. However, results from randomized controlled trials indicate that lung cancer mortality can be reduced by early detection through computed tomography screening. This thesis describes the development of a microsimulation model for the evaluation of lung cancer screening programs, based on individual-level data from two large randomized controlled trials. It then evaluates the long-term benefits and harms of implementing lung cancer screening programs. Finally, it investigates how risk stratification may be used to optimize lung cancer screening programs

Uptake of minimally invasive surgery and stereotactic body radiation therapy for early stage non-small cell lung cancer in the USA

BACKGROUND: We aimed to assess the uptake of minimally invasive surgery (MIS) and stereotactic body radiation therapy (SBRT) among early stage (stage IA-IIB) non-small cell lung cancer (NSCLC) cases in the USA, and the rate of conversions from MIS to open surgery. MATERIALS AND METHODS: Data were obtained from the US National Cancer Database, a nationwide facility-based cancer registry capturing up to 70% of incident cancer cases in the USA. We included cases diagnosed with early stage (clinical stages IA-IIB) NSCLC between 2010 and 2014. In an ecological analysis, we assessed changes in treatment by year of diagnosis. Among surgically treated cases, we assessed the uptake of MIS and whether conversion to open surgery took place. For cases that received thoracic radiotherapy, we assessed the uptake of SBRT. RESULTS: Among 117 370 selected cases, radiotherapy use increased 3.4 percentage points between 2010 and 2014 (p<0.0001). Surgical treatments decreased 3.5 percentage points (p<0.0001). Rates of non-treatment remained stable (range: 10.0%-10.6% (p=0.4066)). Among surgically treated stage IA cases, uptake of MIS increased from 28.7% (95% CI 27.8% to 29.7%) in 2010 to 48.6% (95% CI 47.6% to 49

Cost-effectiveness of risk-based low-dose computed tomography screening for lung cancer in Switzerland

Throughout Europe, computed tomography (CT) screening for lung cancer is in a phase of clinical implementation or reimbursement evaluation. To efficiently select individuals for screening, the use of lung cancer risk models has been suggested, but their incremental (cost-)effectiveness relative to eligibility based on pack-year criteria has not been thoroughly evaluated for a European setting. We evaluate the cost-effectiveness of pack-year and risk-based screening (PLCOm2012 model-based) strategies for Switzerland, which aided in informing the recommendations of the Swiss Cancer Screening Committee (CSC). We use the MISCAN (MIcrosimulation SCreening ANalysis)-Lung model to estimate benefits and harms of screening among individuals born 1940 to 1979 in Switzerland. We evaluate 1512 strategies, differing in the age ranges employed for screening, the screening interval and the strictness of the smoking requirements. We estimate risk-based strategies to be more cost-effective than pack-year-based screening strategies. The most efficient strategy compliant with CSC recommendations is biennial screening for ever-smokers aged 55 to 80 with a 1.6% PLCOm2012 risk. Relative to no screening this strategy is estimated to reduce lung cancer mortality by 11.0%, with estimated costs per Quality-Adjusted Life-Year (QALY) gained of €19 341, and a €1.990 billion 15-year budget impact. Biennial screening ages 55 to 80 for those with 20 pack-years shows a lower mortality reduction (10.5%) and higher cost per QALY gained (€20 869). Despite model uncertainties, our estimates suggest there may be cost-effective screening policies for Switzerland. Risk-based biennial screening ages 55 to 80 for those with ≥1.6% PLCOm2012 risk conforms to CSC recommendations and is estimated to be more efficient than pack-year-based alternatives.</p

Extrapolation of pre-screening trends: Impact of assumptions on overdiagnosis estimates by mammographic screening

Background: Overdiagnosis by mammographic screening is defined as the excess in breast cancer incidence in the presence of screening compared to the incidence in the absence of screening. The latter is often estimated by extrapolating the pre-screening incidence trend. The aim of this theoretical study is to investigate the impact of assumptions in extrapolating the pre-screening incidence trend of invasive breast cancer on the estimated percentage of overdiagnosis. Methods: We extracted data on invasive breast cancer incidence and person-years by calendar year (1975-2009) and 5-year age groups (0-85 years) from Dutch databases. Different combinations of assumptions for extrapolating the pre-screening period were investigated, such as variations in the type of regre

Trends in lung cancer risk and screening eligibility affect overdiagnosis estimates

Objectives: The degree of overdiagnosis due to lung cancer screening in the general US population remains unknown. Estimates may be influenced by the method used and by decreasing smoking trends, which reduce lung cancer risk and screening eligibility over time. Therefore, we aimed to estimate the degree of overdiagnosis due to lung cancer screening in the general US population, using three distinct methods. Material and methods: The MISCAN-Lung model was used to project lung cancer incidence and overdiagnosis in the general US population between 2018–2040, assuming perfect adherence to the United States Preventive Task Force recommendations. MISCAN-Lung was calibrated to the NLST and PLCO trials and incorporates birth-cohort-specific smoking trends and life expectancies. We estimated overdiagnosis using the cumulative excess-incidence approach, the annual excess-incidence approach, and the microsimulation approach. Results: Using the cumulative excess-incidence approach, 10.5 % of screen-detected cases were overdiagnosed in the 1950 birth-cohort compared to 5.9 % in the 1990 birth-cohort. Incidence peaks and drops due to screening were larger for older birth-cohorts than younger birth-cohorts. In the general US population, these differing incidence peaks and drops across birth-cohorts overlap. Therefore, annual excess-incidence would be absent between 2029–2040, suggesting no overdiagnosis occurs. Using the microsimulation approach, overdiagnosis among screen-detected cases increased from 7.1 % to 9.5 % between 2018–2040, while overdiagnosis among all lung cancer cases decreased from 3.7 % to 1.4 %. Conclusion: Overdiagnosis studies should use appropriate methods to account for trends in background risk and screening eligibility in the general population. Estimates from randomized trials, based on the cumulative excess-incidence app