The Impact of Model Assumptions on Personalized Lung Cancer Screening Recommendations

BACKGROUND

Recommendations regarding personalized lung cancer screening are being informed by natural-history modeling. Therefore, understanding how differences in model assumptions affect model-based personalized screening recommendations is essential.

DESIGN

Five Cancer Intervention and Surveillance Modeling Network (CISNET) models were evaluated. Lung cancer incidence, mortality, and stage distributions were compared across 4 theoretical scenarios to assess model assumptions regarding 1) sojourn times, 2) stage-specific sensitivities, and 3) screening-induced lung cancer mortality reductions. Analyses were stratified by sex and smoking behavior.

RESULTS

Most cancers had sojourn times <5 y (model range [MR]; lowest to highest value across models: 83.5%-98.7% of cancers). However, cancer aggressiveness still varied across models, as demonstrated by differences in proportions of cancers with sojourn times <2 y (MR: 42.5%-64.6%) and 2 to 4 y (MR: 28.8%-43.6%). Stage-specific sensitivity varied, particularly for stage I (MR: 31.3%-91.5%). Screening reduced stage IV incidence in most models for 1 y postscreening; increased sensitivity prolonged this period to 2 to 5 y. Screening-induced lung cancer mortality reductions among lung cancers detected at screening ranged widely (MR: 14.6%-48.9%), demonstrating variations in modeled treatment effectiveness of screen-detected cases. All models assumed longer sojourn times and greater screening-induced lung cancer mortality reductions for women. Models assuming differences in cancer epidemiology by smoking behaviors assumed shorter sojourn times and lower screening-induced lung cancer mortality reductions for heavy smokers.

CONCLUSIONS

Model-based personalized screening recommendations are primarily driven by assumptions regarding sojourn times (favoring longer intervals for groups more likely to develop less aggressive cancers), sensitivity (higher sensitivities favoring longer intervals), and screening-induced mortality reductions (greater reductions favoring shorter intervals).

IMPLICATIONS

Models suggest longer screening intervals may be feasible and benefits may be greater for women and light smokers.

HIGHLIGHTS

Natural-history models are increasingly used to inform lung cancer screening, but causes for variations between models are difficult to assess.This is the first evaluation of these causes and their impact on personalized screening recommendations through easily interpretable metrics.Models vary regarding sojourn times, stage-specific sensitivities, and screening-induced lung cancer mortality reductions.Model outcomes were similar in predicting greater screening benefits for women and potentially light smokers. Longer screening intervals may be feasible for women and light smokers.

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.

Assessing the impact of increasing lung screening eligibility by relaxing the maximum years-since-quit threshold: A simulation modeling study

BACKGROUND

In 2021, the US Preventive Services Task Force expanded its lung screening recommendation to include persons aged 50-80 years who had ever smoked and had at least 20 pack-years of exposure and less than 15 years since quitting (YSQ). However, studies have suggested that screening persons who formerly smoked with longer YSQ could be beneficial.

METHODS

The authors used two validated lung cancer models to assess the benefits and harms of screening using various YSQ thresholds (10, 15, 20, 25, 30, and no YSQ) and the age at which screening was stopped. The impact of enforcing the YSQ criterion only at entry, but not at exit, also was evaluated. Outcomes included the number of screens, the percentage ever screened, screening benefits (lung cancer deaths averted, life-years gained), and harms (false-positive tests, overdiagnosed cases, radiation-induced lung cancer deaths). Sensitivity analyses were conducted to evaluate the effect of restricting screening to those who had at least 5 years of life expectancy.

RESULTS

As the YSQ criterion was relaxed, the number of screens and the benefits and harms of screening increased. Raising the age at which to stop screening age resulted in additional benefits but with more overdiagnosis, as expected, because screening among those older than 80 years increased. Limiting screening to those who had at least 5 years of life expectancy would maintain most of the benefits while considerably reducing the harms.

CONCLUSIONS

Expanding screening to persons who formerly smoked and have greater than 15 YSQ would result in considerable increases in deaths averted and life-years gained. Although additional harms would occur, these could be moderated by ensuring that screening is restricted to only those with reasonable life expectancy.

Risk Model-Based Lung Cancer Screening : A Cost-Effectiveness Analysis

BACKGROUND

In their 2021 lung cancer screening recommendation update, the U.S. Preventive Services Task Force (USPSTF) evaluated strategies that select people based on their personal lung cancer risk (risk model-based strategies), highlighting the need for further research on the benefits and harms of risk model-based screening.

OBJECTIVE

To evaluate and compare the cost-effectiveness of risk model-based lung cancer screening strategies versus the USPSTF recommendation and to explore optimal risk thresholds.

DESIGN

Comparative modeling analysis.

DATA SOURCES

National Lung Screening Trial; Surveillance, Epidemiology, and End Results program; U.S. Smoking History Generator.

TARGET POPULATION

1960 U.S. birth cohort.

TIME HORIZON

45 years.

PERSPECTIVE

U.S. health care sector.

INTERVENTION

Annual low-dose computed tomography in risk model-based strategies that start screening at age 50 or 55 years, stop screening at age 80 years, with 6-year risk thresholds between 0.5% and 2.2% using the PLCOm2012 model.

OUTCOME MEASURES

Incremental cost-effectiveness ratio (ICER) and cost-effectiveness efficiency frontier connecting strategies with the highest health benefit at a given cost.

RESULTS OF BASE-CASE ANALYSIS

Risk model-based screening strategies were more cost-effective than the USPSTF recommendation and exclusively comprised the cost-effectiveness efficiency frontier. Among the strategies on the efficiency frontier, those with a 6-year risk threshold of 1.2% or greater were cost-effective with an ICER less than $100 000 per quality-adjusted life-year (QALY). Specifically, the strategy with a 1.2% risk threshold had an ICER of $94 659 (model range, $72 639 to $156 774), yielding more QALYs for less cost than the USPSTF recommendation, while having a similar level of screening coverage (person ever-screened 21.7% vs. USPSTF's 22.6%).

RESULTS OF SENSITIVITY ANALYSES

Risk model-based strategies were robustly more cost-effective than the 2021 USPSTF recommendation under varying modeling assumptions.

LIMITATION

Risk models were restricted to age, sex, and smoking-related risk predictors.

CONCLUSION

Risk model-based screening is more cost-effective than the USPSTF recommendation, thus warranting further consideration.

PRIMARY FUNDING SOURCE

National Cancer Institute (NCI).

Selection of eligible participants for screening for lung cancer using primary care data

Lung cancer screening is effective if offered to people at increased risk of the disease. Currently, direct contact with potential participants is required for evaluating risk. A way to reduce the number of ineligible people contacted might be to apply risk-prediction models directly to digital primary care data, but model performance in this setting is unknown.

METHOD

The Clinical Practice Research Datalink, a computerised, longitudinal primary care database, was used to evaluate the Liverpool Lung Project V.2 (LLP_v2) and Prostate Lung Colorectal and Ovarian (modified 2012) (PLCO_m2012) models. Lung cancer occurrence over 5-6 years was measured in ever-smokers aged 50-80 years and compared with 5-year (LLP_v2) and 6-year (PLCO_m2012) predicted risk.

RESULTS

Over 5 and 6 years, 7123 and 7876 lung cancers occurred, respectively, from a cohort of 842 109 ever-smokers. After recalibration, LLP_V2 produced a c-statistic of 0.700 (0.694-0.710), but mean predicted risk was over-estimated (predicted: 4.61%, actual: 0.9%). PLCO_m2012 showed similar performance (c-statistic: 0.679 (0.673-0.685), predicted risk: 3.76%. Applying risk-thresholds of 1% (LLP_v2) and 0.15% (PLCO_m2012), would avoid contacting 42.7% and 27.4% of ever-smokers who did not develop lung cancer for screening eligibility assessment, at the cost of missing 15.6% and 11.4% of lung cancers.

CONCLUSION

Risk-prediction models showed only moderate discrimination when applied to routinely collected primary care data, which may be explained by quality and completeness of data. However, they may substantially reduce the number of people for initial evaluation of screening eligibility, at the cost of missing some lung cancers. Further work is needed to establish whether newer models have improved performance in primary care data.

Modeling Strategies to Optimize Cancer Screening in USPSTF Guideline-Noncompliant Women

Importance

In 2018, only half of US women obtained all evidence-based cancer screenings. This proportion may have declined during the COVID-19 pandemic because of social distancing, high-risk factors, and fear.

Objective

To evaluate optimal screening strategies in women who obtain some, but not all, US Preventive Services Task Force (USPSTF)-recommended cancer screenings.

Design, Setting, and Participants

This modeling study was conducted from January 31, 2017, to July 20, 2020, and used 4 validated mathematical models from the National Cancer Institute's Cancer Intervention and Surveillance Modeling Network using data from 20 million simulated women born in 1965 in the US.

Interventions

Forty-five screening strategies were modeled that combined breast, cervical, colorectal, and/or lung cancer (LC) screenings; restricted to 1, 2, 3 or 4 screenings per year; or all eligible screenings once every 5 years.

Main Outcomes and Measures

Modeled life-years gained from restricted cancer screenings as a fraction of those attainable from full compliance with USPSTF recommendations (maximum benefits). Results were stratified by LC screening eligibility (LC-eligible/ineligible). We repeated the analysis with 2018 adherence rates, evaluating the increase in adherence required for restricted screenings to have the same population benefit as USPSTF recommendations.

Results

This modeling study of 20 million simulated US women found that it was possible to reduce screening intensity to 1 carefully chosen test per year in women who were ineligible for LC screening and 2 tests per year in eligible women while maintaining 94% or more of the maximum benefits. Highly ranked strategies screened for various cancers, but less often than recommended by the USPSTF. For example, among LC-ineligible women who obtained just 1 screening per year, the optimal strategy frequently delayed breast and cervical cancer screenings by 1 year and skipped 3 mammograms entirely. Among LC-eligible women, LC screening was essential; strategies omitting it provided 25% or less of the maximum benefits. The top-ranked strategy restricted to 2 screenings per year was annual LC screening and alternating fecal immunochemical test with mammography (skipping mammograms when due for cervical cancer screening, 97% of maximum benefits). If adherence in a population of LC-eligible women obtaining 2 screenings per year were to increase by 1% to 2% (depending on the screening test), this model suggests that it would achieve the same benefit as USPSTF recommendations at 2018 adherence rates.

Conclusions and Relevance

This modeling study of 45 cancer screening strategies suggests that women who are noncompliant with cancer screening guidelines may be able to reduce USPSTF-recommended screening intensity with minimal reduction in overall benefits.

Disparities of National Lung Cancer Screening Guidelines in the US Population

BACKGROUND

Current US Preventive Services Task Force (USPSTF) lung cancer screening guidelines are based on smoking history and age (55-80 years). These guidelines may miss those at higher risk, even at lower exposures of smoking or younger ages, because of other risk factors such as race, family history, or comorbidity. In this study, we characterized the demographic and clinical profiles of those selected by risk-based screening criteria but were missed by USPSTF guidelines in younger (50-54 years) and older (71-80 years) age groups.

METHODS

We used data from the National Health Interview Survey, the CISNET Smoking History Generator, and results of logistic prediction models to simulate lifetime lung cancer risk-factor data for 100 000 individuals in the 1950-1960 birth cohorts. We calculated age-specific 6-year lung cancer risk for each individual from ages 50 to 90 years using the PLCOm2012 model and evaluated age-specific screening eligibility by USPSTF guidelines and by risk-based criteria (varying thresholds between 1.3% and 2.5%).

RESULTS

In the 1950 birth cohort, 5.4% would have been ineligible for screening by USPSTF criteria in their younger ages but eligible based on risk-based criteria. Similarly, 10.4% of the cohort would be ineligible for screening by USPSTF in older ages. Notably, high proportions of blacks were ineligible for screening by USPSTF criteria at younger (15.6%) and older (14.2%) ages, which were statistically significantly greater than those of whites (4.8% and 10.8%, respectively; P < .001). Similar results were observed with other risk thresholds and for the 1960 cohort.

CONCLUSIONS

Further consideration is needed to incorporate comprehensive risk factors, including race and ethnicity, into lung cancer screening to reduce potential racial disparities.

Personalising lung cancer screening: An overview of risk-stratification opportunities and challenges

Randomised clinical trials have shown the efficacy of computed tomography lung cancer screening, initiating discussions on whether and how to implement population‐based screening programs. Due to smoking behaviour being the primary risk‐factor for lung cancer and part of the criteria for determining screening eligibility, lung cancer screening is inherently risk‐based. In fact, the selection of high‐risk individuals has been shown to be essential in implementing lung cancer screening in a cost‐effective manner. Furthermore, studies have shown that further risk‐stratification may improve screening efficiency, allow personalisation of the screening interval and reduce health disparities. However, implementing risk‐based lung cancer screening programs also requires overcoming a number of challenges. There are indications that risk‐based approaches can negatively influence the trade‐off between individual benefits and harms if not applied thoughtfully. Large‐scale implementation of targeted, risk‐based screening programs has been limited thus far. Consequently, questions remain on how to efficiently identify and invite high‐risk individuals from the general population. Finally, while risk‐based approaches may increase screening program efficiency, efficiency should be balanced with the overall impact of the screening program. In this review, we will address the opportunities and challenges in applying risk‐stratification in different aspects of lung cancer screening programs, as well as the balance between screening program efficiency and impact.

Cost-effectiveness Analysis of Breast Cancer Screening Using Mammography in Singapore: A Modeling Study

BACKGROUND

Limited research is available on the cost-effectiveness of breast cancer screening programs in Asian countries. We evaluated the cost-effectiveness of Singapore's national mammography screening program, implemented in 2002, recommending annual screening between ages 40 and 49 and biennial screening between ages 50 and 69, and alternative screening scenarios taking into account important country-specific factors.

METHODS

We used national data from Singapore in the MIcrosimulation SCreening ANalysis-Fatal diameter (MISCAN-Fadia) model to simulate 302 screening scenarios for 10 million women born between 1910 and 1969. Screening scenarios varied by starting and ending age, screening interval, and attendance. Outcome measures included life-years gained (LYG), breast cancer deaths averted, false positives, overdiagnosis, quality-adjusted life years (QALY), costs (in 2002 Singapore dollars; S$), and incremental cost-effectiveness ratios (ICER). Costs and effects were calculated and discounted with 3% using a health care provider's perspective.

RESULTS

Singapore's current screening program at observed attendance levels required 54,158 mammograms per 100,000 women, yielded 1,054 LYG, and averted 57 breast cancer deaths. At attendance rates ≥50%, the current program was near the efficiency frontier. Most scenarios on the efficiency frontier started screening at age 40. The ICERs of the scenarios on the efficiency frontiers ranged between S$10,186 and S$56,306/QALY, which is considered cost-effective at a willingness-to-pay threshold of S$70,000/QALY gained.

CONCLUSIONS

Singapore's current screening program lies near the efficiency frontier, and starting screening at age 40 or 45 is cost-effective. Furthermore, enhancing screening attendance rates would increase benefits while maintaining cost-effectiveness.

IMPACT

Screening all women at age 40 or 45 is cost-efficient in Singapore, and a policy change may be considered.

Implementation of lung cancer screening: what are the main issues?

Two large-scale RCTs have shown computed tomography (CT) lung cancer screening to be efficacious in reducing lung cancer mortality (8–24% in men, 26–59% in women). However, lung cancer screening implicitly means personalised and risk-based approaches. Health care systems’ implementation of personalised screening and prevention is still sparse, and likely to be of variable quality, because of important remaining uncertainties, which have been incompletely addressed or not at all so far. Further optimisation of lung cancer screening programs is expected to reduce harms and maintain or enhance benefit for eligible European citizens, whilst significantly reducing health care costs. Some main uncertainties (e.g., Risk-based eligibility, Risk-based screening intervals, Volume CT screening, Smoking Cessation, Gender and Sex differences, Cost-Effectiveness) are discussed in this review. 4-IN-THE-LUNG-RUN (acronym for: Towards INdividually tailored INvitations, screening INtervals and INtegrated co-morbidity reducing strategies in lung cancer screening) is the first multi-centred implementation trial on volume CT lung cancer screening amongst 24,000 males and females, at high risk for developing lung cancer, across five European countries, started in January 2020. Through providing answers to the remaining questions with this trial, many EU citizens will swiftly benefit from this high-quality screening technology, others will face less harms than previously anticipated, and health care costs will be substantially reduced. Implementing a new cancer screening programme is a major task, with many stakeholders and many possible facilitators but also barriers and obstacle.

A Comparative Modeling Analysis of Risk-Based Lung Cancer Screening Strategies

BACKGROUND

Risk-prediction models have been proposed to select individuals for lung cancer screening. However, their long-term effects are uncertain. This study evaluates long-term benefits and harms of risk-based screening compared with current United States Preventive Services Task Force (USPSTF) recommendations.

METHODS

Four independent natural history models were used to perform a comparative modeling study evaluating long-term benefits and harms of selecting individuals for lung cancer screening through risk-prediction models. In total, 363 risk-based screening strategies varying by screening starting and stopping age, risk-prediction model used for eligibility (Bach, PLCOm2012, or Lung Cancer Death Risk Assessment Tool [LCDRAT]), and risk threshold were evaluated for a 1950 US birth cohort. Among the evaluated outcomes were percentage of individuals ever screened, screens required, lung cancer deaths averted, life-years gained, and overdiagnosis.

RESULTS

Risk-based screening strategies requiring similar screens among individuals ages 55-80 years as the USPSTF criteria (corresponding risk thresholds: Bach = 2.8%; PLCOm2012 = 1.7%; LCDRAT = 1.7%) averted considerably more lung cancer deaths (Bach = 693; PLCOm2012 = 698; LCDRAT = 696; USPSTF = 613). However, life-years gained were only modestly higher (Bach = 8660; PLCOm2012 = 8862; LCDRAT = 8631; USPSTF = 8590), and risk-based strategies had more overdiagnosed cases (Bach = 149; PLCOm2012 = 147; LCDRAT = 150; USPSTF = 115). Sensitivity analyses suggest excluding individuals with limited life expectancies (<5 years) from screening retains the life-years gained by risk-based screening, while reducing overdiagnosis by more than 65.3%.

CONCLUSIONS

Risk-based lung cancer screening strategies prevent considerably more lung cancer deaths than current recommendations do. However, they yield modest additional life-years and increased overdiagnosis because of predominantly selecting older individuals. Efficient implementation of risk-based lung cancer screening requires careful consideration of life expectancy for determining optimal individual stopping ages.

Systematic Review and Meta-Analysis of Community- and Choice-Based Health State Utility Values for Lung Cancer

BACKGROUND

Using appropriate health state utility values (HSUVs) is critical for economic evaluation of new lung cancer interventions, such as low-dose computed tomography screening and immunotherapy. Therefore, we provide a systematic review and meta-analysis of community- and choice-based HSUVs for lung cancer.

METHODS

On 6 March 2017, we conducted a systematic search of the following databases: Embase, Ovid MEDLINE, Web of Science, Cochrane CENTRAL, Google Scholar, and the School of Health and Related Research Health Utility Database. The search was updated on 17 April 2019. Studies reporting mean or median lung cancer-specific HSUVs including a measure of variance were included and assessed for relevance and validity. Studies with high relevance (i.e. community- and choice-based) were further analysed. Mean HSUVs were pooled using random-effects models for all stages, stages I-II, and stages III-IV. For studies with a control group, we calculated the disutility due to lung cancer. A sensitivity analysis included only the methodologically most comparable studies (i.e. using the EQ-5D instrument and matching tariff). Subgroup analyses were conducted by time to death, histology, sex, age, treatment modality, treatment line, and progression status.

RESULTS

We identified and analysed 27 studies of high relevance. The pooled HSUV was 0.68 (95% confidence interval [CI] 0.61-0.75) for all stages, 0.78 (95% CI 0.70-0.86) for stages I-II, and 0.69 (95% CI 0.65-0.73) for stages III-IV (p = 0.02 vs. stage I-II). Heterogeneity was present in each pooled analysis (p < 0.01; I2 = 92-99%). Disutility due to lung cancer ranged from 0.11 (95% CI 0.05-0.17) to 0.27 (95% CI 0.18-0.36). In the sensitivity analysis with the methodologically most comparable studies, stage-specific HSUVs varied by country. Such studies were only identified for Canada, China, Spain, the UK, the USA, Denmark, Germany, and Thailand. In the subgroup analysis by time to death, HSUVs for metastatic non-small-cell lung cancer ranged from 0.83 (95% CI 0.82-0.85) at ≥ 360 days from death to 0.56 (95% CI 0.46-0.66) at < 30 days from death. Among patients with metastatic non-small-cell lung cancer, HSUVs were lower for those receiving third- or fourth-line treatment and for those with progressed disease. Results of subgroup analyses by histology, sex, age, and treatment modality were ambiguous.

CONCLUSIONS

The presented evidence supports the use of stage- and country-specific HSUVs. However, such HSUVs are unavailable for most countries. Therefore, our pooled HSUVs may provide the best available stage-specific HSUVs for most countries. For metastatic non-small-cell lung cancer, adjusting for the decreased HSUVs in the last year of life may be considered, as may further stratification of HSUVs by treatment line or progression status. If required, HSUVs for other health states may be identified using our comprehensive breakdown of study characteristics.

Correction: Risk prediction models for selection of lung cancer screening candidates: A retrospective validation study

[This corrects the article DOI: 10.1371/journal.pmed.1002277.].

Uptake of minimally invasive surgery and stereotactic body radiation therapy for early stage non-small cell lung cancer in the USA: an ecological study of secular trends using the National Cancer Database

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 49.6%) in 2014 (p<0.0001), while conversions decreased from 17.0% (95% CI 15.6% to 18.6%) in 2010 to 9.1% (95% CI 8.3% to 10.0%) in 2014 (p<0.0001). MIS uptake among stages IB-IIB was lower and conversion rates were higher, but time trends were similar. Uptake of SBRT among stage IA receiving thoracic radiotherapy increased from 53.4% (95% CI 51.2% to 55.6%) in 2010 to 73.0% (95% CI 71.4% to 74.6%) in 2014 (p<0.0001). SBRT uptake among stage IB increased from 32.5% (95% CI 29.9% to 35.2%) in 2010 to 48.2% (95% CI 45.6% to 50.8%) in 2014 (p<0.0001).

CONCLUSION

Between 2010 and 2014, uptake of MIS and SBRT among early stage NSCLC significantly increased, while the rate of conversions to open surgery significantly decreased. Continuing these trends may contribute to improving patient care, in particular with the expected increase in early stages due to the implementation of lung cancer screening.

Reduced Lung-Cancer Mortality with Volume CT Screening in a Randomized Trial

BACKGROUND

There are limited data from randomized trials regarding whether volume-based, low-dose computed tomographic (CT) screening can reduce lung-cancer mortality among male former and current smokers.

METHODS

A total of 13,195 men (primary analysis) and 2594 women (subgroup analyses) between the ages of 50 and 74 were randomly assigned to undergo CT screening at T0 (baseline), year 1, year 3, and year 5.5 or no screening. We obtained data on cancer diagnosis and the date and cause of death through linkages with national registries in the Netherlands and Belgium, and a review committee confirmed lung cancer as the cause of death when possible. A minimum follow-up of 10 years until December 31, 2015, was completed for all participants.

RESULTS

Among men, the average adherence to CT screening was 90.0%. On average, 9.2% of the screened participants underwent at least one additional CT scan (initially indeterminate). The overall referral rate for suspicious nodules was 2.1%. At 10 years of follow-up, the incidence of lung cancer was 5.58 cases per 1000 person-years in the screening group and 4.91 cases per 1000 person-years in the control group; lung-cancer mortality was 2.50 deaths per 1000 person-years and 3.30 deaths per 1000 person-years, respectively. The cumulative rate ratio for death from lung cancer at 10 years was 0.76 (95% confidence interval [CI], 0.61 to 0.94; P = 0.01) in the screening group as compared with the control group, similar to the values at years 8 and 9. Among women, the rate ratio was 0.67 (95% CI, 0.38 to 1.14) at 10 years of follow-up, with values of 0.41 to 0.52 in years 7 through 9.

CONCLUSIONS

In this trial involving high-risk persons, lung-cancer mortality was significantly lower among those who underwent volume CT screening than among those who underwent no screening. There were low rates of follow-up procedures for results suggestive of lung cancer. (Funded by the Netherlands Organization of Health Research and Development and others; NELSON Netherlands Trial Register number, NL580.).

Cost-Effectiveness Analysis of Lung Cancer Screening in the United States: A Comparative Modeling Study

BACKGROUND

Recommendations vary regarding the maximum age at which to stop lung cancer screening: 80 years according to the U.S. Preventive Services Task Force (USPSTF), 77 years according to the Centers for Medicare & Medicaid Services (CMS), and 74 years according to the National Lung Screening Trial (NLST).

OBJECTIVE

To compare the cost-effectiveness of different stopping ages for lung cancer screening.

DESIGN

By using shared inputs for smoking behavior, costs, and quality of life, 4 independently developed microsimulation models evaluated the health and cost outcomes of annual lung cancer screening with low-dose computed tomography (LDCT).

DATA SOURCES

The NLST; Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial; SEER (Surveillance, Epidemiology, and End Results) program; Nurses' Health Study and Health Professionals Follow-up Study; and U.S. Smoking History Generator.

TARGET POPULATION

Current, former, and never-smokers aged 45 years from the 1960 U.S. birth cohort.

TIME HORIZON

45 years.

PERSPECTIVE

Health care sector.

INTERVENTION

Annual LDCT according to NLST, CMS, and USPSTF criteria.

OUTCOME MEASURES

Incremental cost-effectiveness ratios (ICERs) with a willingness-to-pay threshold of $100 000 per quality-adjusted life-year (QALY).

RESULTS OF BASE-CASE ANALYSIS

The 4 models showed that the NLST, CMS, and USPSTF screening strategies were cost-effective, with ICERs averaging $49 200, $68 600, and $96 700 per QALY, respectively. Increasing the age at which to stop screening resulted in a greater reduction in mortality but also led to higher costs and overdiagnosis rates.

RESULTS OF SENSITIVITY ANALYSIS

Probabilistic sensitivity analysis showed that the NLST and CMS strategies had higher probabilities of being cost-effective (98% and 77%, respectively) than the USPSTF strategy (52%).

LIMITATION

Scenarios assumed 100% screening adherence, and models extrapolated beyond clinical trial data.

CONCLUSION

All 3 sets of lung cancer screening criteria represent cost-effective programs. Despite underlying uncertainty, the NLST and CMS screening strategies have high probabilities of being cost-effective.

PRIMARY FUNDING SOURCE

CISNET (Cancer Intervention and Surveillance Modeling Network) Lung Group, National Cancer Institute.

All-cause mortality versus cancer-specific mortality as outcome in cancer screening trials: A review and modeling study

BACKGROUND

All-cause mortality has been suggested as an end-point in cancer screening trials in order to avoid biases in attributing the cause of death. The aim of this study was to investigate which sample size and follow-up is needed to find a significant reduction in all-cause mortality.

METHODS

A literature review was conducted to identify previous studies that modeled the effect of screening on all-cause mortality. Microsimulation modeling was used to simulate breast cancer, lung cancer, and colorectal cancer screening trials. Model outputs were: cancer-specific deaths, all-cause deaths, and life-years gained per year of follow-up.

RESULTS

There were large differences between the evaluated cancers. For lung cancer, when 40 000 high-risk people are randomized to each arm, a significant reduction in all-cause mortality could be expected between 11 and 13 years of follow-up. For breast cancer, a significant reduction could be found between 16 and 26 years of follow-up for a sample size of over 300 000 women in each arm. For colorectal cancer, 600 000 persons in each arm were required to be followed for 15-20 years. Our systematic literature review identified seven papers, which showed highly similar results to our estimates.

CONCLUSION

Cancer screening trials are able to demonstrate a significant reduction in all-cause mortality due to screening, but require very large sample sizes. Depending on the cancer, 40 000-600 000 participants per arm are needed to demonstrate a significant reduction. The reduction in all-cause mortality can only be detected between specific years of follow-up, more limited than the timeframe to detect a reduction in cancer-specific mortality.

Treatment capacity required for full-scale implementation of lung cancer screening in the United States

Background

Full‐scale implementation of lung cancer screening in the United States will increase detection of early stages. This study was aimed at assessing the capacity required for treating those cancers.

Methods

A well‐established microsimulation model was extended with treatment data from the National Cancer Database. We assessed how treatment demand would change when implementing lung cancer screening in 2018. Three policies were assessed: 1) annual screening of current smokers and former smokers who quit fewer than 15 years ago, aged 55 to 80 years, with a smoking history of at least 30 pack‐years (US Preventive Services Task Force [USPSTF] recommendations); 2) annual screening of current smokers and former smokers who quit fewer than 15 years ago, aged 55 to 77 years, with a smoking history of at least 30 pack‐years (Centers for Medicare and Medicaid Services [CMS] recommendations); and 3) annual screening of current smokers and former smokers who quit fewer than 10 years ago, aged 55 to 75 years, with a smoking history of at least 40 pack‐years (the most cost‐effective policy in Ontario [Ontario]). The base‐case screening adherence was a constant 50%. Sensitivity analyses assessed other adherence levels, including a linear buildup to 50% between 2018 and 2027.

Results

The USPSTF policy would require 37.0% more lung cancer surgeries in 2015‐2040 than no screening, 2.2% less radiotherapy, and 5.4% less chemotherapy; 5.7% more patients would require any therapy. The increase in surgical demand would be 96.1% in 2018, 46.0% in 2023, 38.3% in 2028, and 24.9% in 2040. Adherence strongly influenced results. By 2018, surgical demand would range from 52,619 (20% adherence) to 96,121 (80%). With a gradual buildup of adherence, the increase in surgical demand would be 9.6% in 2018, 38.3% in 2023, 42.0% in 2028, and 24.4% in 2040. Results for the CMS and Ontario policies were similar, although the changes in comparison with no screening were smaller.

Conclusions

Full‐scale implementation of lung cancer screening causes a major increase in surgical demand, with a peak within the first 5 years. A gradual buildup of adherence can spread this peak over time. Careful surgical capacity planning is essential for successfully implementing screening.

Full‐scale implementation of lung cancer screening in the United States will lead to a major increase in the demand for thoracic surgery. Careful surgical capacity planning is essential for successfully implementing screening.

Persisting new nodules in incidence rounds of the NELSON CT lung cancer screening study

BACKGROUND

The US guidelines recommend low-dose CT (LDCT) lung cancer screening for high-risk individuals. New solid nodules after baseline screening are common and have a high lung cancer probability. Currently, no evidence exists concerning the risk stratification of non-resolving new solid nodules at first LDCT screening after initial detection.

METHODS

In the Dutch-Belgian Randomized Lung Cancer Screening (NELSON) trial, 7295 participants underwent the second and 6922 participants the third screening round. We included participants with solid nodules that were registered as new or <15 mm³ (study detection limit) at previous screens and received additional screening after initial detection, thereby excluding high-risk nodules according to the NELSON management protocol (nodules ≥500 mm³).

RESULTS

Overall, 680 participants with 1020 low-risk and intermediate-risk new solid nodules were included. A total of 562 (55%) new solid nodules were resolving, leaving 356 (52%) participants with a non-resolving new solid nodule, of whom 25 (7%) were diagnosed with lung cancer. At first screening after initial detection, volume doubling time (VDT), volume, and VDT combined with a predefined ≥200 mm³ volume cut-off had high discrimination for lung cancer (VDT, area under the curve (AUC): 0.913; volume, AUC: 0.875; VDT and ≥200 mm³ combination, AUC: 0.939). Classifying a new solid nodule with either ≤590 days VDT or ≥200 mm³ volume positive provided 100% sensitivity, 84% specificity and 27% positive predictive value for lung cancer.

CONCLUSIONS

More than half of new low-risk and intermediate-risk solid nodules in LDCT lung cancer screening resolve. At follow-up, growth assessment potentially combined with a volume limit can be used for risk stratification.

TRIAL REGISTRATION NUMBER

ISRCTN63545820; pre-results.

Cost-effectiveness of low-dose CT screening for lung cancer in a European country with high prevalence of smoking-A modelling study

OBJECTIVES

In Europe, there is uncertainty about the potential effects and cost-effectiveness of low dose computed tomography screening for lung cancer and about the applicability of results of North American studies. We aimed to estimate the effects and cost-effectiveness of lung cancer screening in a population-based setting in Switzerland where the smoking prevalence is high.

MATERIALS AND METHODS

The MIcrosimulation Screening ANalysis-Lung (MISCAN) model was adapted using country specific input parameters regarding lung cancer epidemiology, smoking behaviours, and treatment costs. The effects and costs of 648 screening scenarios with different screening start and stop ages, smoking eligibility criteria, and screening intervals were examined from a public healthcare system perspective across a lifetime horizon in a cohort born between 1935 and 1965.

RESULTS

All screening scenarios showed an increase in the total number of detected lung cancer cases and a decrease in lung cancer mortality. On the efficiency frontier, 15 of 27 scenarios showed incremental cost-effectiveness ratios below € 50,000 per life year gained. These scenarios reduced lung cancer mortality by 6-15% while increasing incidence of lung cancer diagnoses by 2-6%.

CONCLUSION

These results suggest that lung cancer screening may be cost-effective in Switzerland, a high-income, European country with high smoking prevalence.

Lung cancer screening: latest developments and unanswered questions

The US National Lung Screening Trial showed that individuals randomly assigned to screening with low-dose CT scans had 20% lower lung cancer mortality than did those screened with conventional chest radiography. On the basis of a review of the literature and a modelling study, the US Preventive Services Task Force recommends annual screening for lung cancer for individuals aged 55-80 years who have a 30 pack-year smoking history and either currently smoke or quit smoking within the past 15 years. However, the balance between benefits and harms of lung cancer screening is still greatly debated. The large number of false-positive results and the potential for overdiagnosis are causes for concern. Some investigators suggest the ratio between benefits and harms could be improved through various means. Nevertheless, many questions remain with regard to the implementation of lung cancer screening. This paper highlights the latest developments in CT lung cancer screening and provides an overview of the main unanswered questions.

Quantifying Overdiagnosis in Cancer Screening: A Systematic Review to Evaluate the Methodology

Background

Overdiagnosis is the main harm of cancer screening programs but is difficult to quantify. This review aims to evaluate existing approaches to estimate the magnitude of overdiagnosis in cancer screening in order to gain insight into the strengths and limitations of these approaches and to provide researchers with guidance to obtain reliable estimates of overdiagnosis in cancer screening.

Methods

A systematic review was done of primary research studies in PubMed that were published before January 1, 2016, and quantified overdiagnosis in breast cancer screening. The studies meeting inclusion criteria were then categorized by their methods to adjust for lead time and to obtain an unscreened reference population. For each approach, we provide an overview of the data required, assumptions made, limitations, and strengths.

Results

A total of 442 studies were identified in the initial search. Forty studies met the inclusion criteria for the qualitative review. We grouped the approaches to adjust for lead time in two main categories: the lead time approach and the excess incidence approach. The lead time approach was further subdivided into the mean lead time approach, lead time distribution approach, and natural history modeling. The excess incidence approach was subdivided into the cumulative incidence approach and early vs late-stage cancer approach. The approaches used to obtain an unscreened reference population were grouped into the following categories: control group of a randomized controlled trial, nonattenders, control region, extrapolation of a prescreening trend, uninvited groups, adjustment for the effect of screening, and natural history modeling.

Conclusions

Each approach to adjust for lead time and obtain an unscreened reference population has its own strengths and limitations, which should be taken into consideration when estimating overdiagnosis.

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.

Risk stratification based on screening history: the NELSON lung cancer screening study

BACKGROUND

Debate about the optimal lung cancer screening strategy is ongoing. In this study, previous screening history of the Dutch-Belgian Lung Cancer Screening trial (NELSON) is investigated on if it predicts the screening outcome (test result and lung cancer risk) of the final screening round.

METHODS

15 792 participants were randomised (1:1) of which 7900 randomised into a screening group. CT screening took place at baseline, and after 1, 2 and 2.5 years. Initially, three screening outcomes were possible: negative, indeterminate or positive scan result. Probability for screening outcome in the fourth round was calculated for subgroups of participants.

RESULTS

Based on results of the first three rounds, three subgroups were identified: (1) those with exclusively negative results (n=3856; 73.0%); (2) those with ≥1 indeterminate result, but never a positive result (n=1342; 25.5%); and (3) with ≥1 positive result (n=81; 1.5%). Group 1 had the highest probability for having a negative scan result in round 4 (97.2% vs 94.8% and 90.1%, respectively, p<0.001), and the lowest risk for detecting lung cancer in round 4 (0.6% vs 1.6%, p=0.001). 'Smoked pack-years' and 'screening history' significantly predicted the fourth round test result. The third round results implied that the risk for detecting lung cancer (after an interval of 2.5 years) was 0.6% for those with negative results compared with 3.7% of those with indeterminate results.

CONCLUSIONS

Previous CT lung cancer screening results provides an opportunity for further risk stratifications of those who undergo lung cancer screening.

TRIAL REGISTRATION NUMBER

Results, ISRCTN63545820.

Lung cancer detectability by test, histology, stage, and gender: estimates from the NLST and the PLCO trials

BACKGROUND

Implementing optimal lung cancer screening programs requires knowledge of the natural history and detectability of lung cancer. This information can be derived from the results of clinical trials with the aid of microsimulation models.

METHODS

Data from the Surveillance, Epidemiology, and End Results (SEER) program and individual-level data from the National Lung Screening Trial (NLST) and the Prostate, Lung, Colon, and Ovarian Cancer Screening trial (PLCO) were used to investigate the sensitivity (by histology and stage) of CT and chest radiography (CXR) and the mean preclinical sojourn time (MPST) of lung cancer (by gender, histology, and stage). The MISCAN-Lung model was used to reproduce the lung cancer incidence by method of detection (clinically or screen-detected), gender, histology, and stage in both trials and SEER, by calibrating CT and CXR sensitivity and natural history parameters.

RESULTS

CT sensitivity ranges from 8.83% to 99.35% and CXR sensitivity from 2.51% to 97.31%, depending on histology and stage. CT sensitivity for stage IA is more than 3-fold higher compared with CXR, for all histologies. The total MPST estimates for lung cancer progressing through preclinical stages IA to IV range from 3.09 to 5.32 years for men and 3.35 to 6.01 years for women. The largest difference in total MPST between genders was estimated for adenocarcinoma.

CONCLUSIONS

We estimate longer MPSTs for lung cancer compared with previous research, suggesting a greater window of opportunity for lung cancer screening.

IMPACT

This study provides detailed insights into the natural history of lung cancer and CT screening effectiveness.