Exploring Structural Uncertainty in Cost-Effectiveness Modeling of Gestational Diabetes Screening: An Application Example from Norway

BACKGROUND

Screening pregnant women for gestational diabetes mellitus (GDM) has recently been expanded in Norway, although screening eligibility criteria continue to be debated. We aimed to compare the cost-effectiveness of alternative GDM screening strategies and explored structural uncertainty and the value of future research in determining the most cost-effective eligibility criteria for GDM screening in Norway.

DESIGN

We developed a probabilistic decision tree to estimate the total costs and health benefits (i.e., quality-adjusted life-years; QALYs) associated with 4 GDM screening strategies (universal, current guidelines, high-risk, and no screening). We identified the most cost-effective strategy as the strategy with the highest incremental cost-effectiveness ratio below a Norwegian benchmark for cost-effectiveness ($28,400/QALY). We excluded inconclusive evidence on the effects of screening on later maternal type 2 diabetes mellitus (T2DM) in the primary analysis but included this outcome in a secondary analysis using 2 different sources of evidence (i.e., Cochrane or US Preventive Services Task Force). To quantify decision uncertainty, we conducted scenario analysis and value-of-information analyses.

RESULTS

Current screening recommendations were considered inefficient in all analyses, while universal screening was most cost-effective in our primary analysis ($26,014/QALY gained) and remained most cost-effective when we assumed a preventive effect of GDM treatment on T2DM. When we assumed no preventive effect, high-risk screening was preferred ($19,115/QALY gained). When we assumed GDM screening does not prevent perinatal death in scenario analysis, all strategies except no screening exceeded the cost-effectiveness benchmark. In most analyses, decision uncertainty was high.

CONCLUSIONS

The most cost-effective screening strategy, ranging from no screening to universal screening, depended on the source and inclusion of GDM treatment effects on perinatal death and T2DM. Further research on these long-term outcomes could reduce decision uncertainty.

HIGHLIGHTS

This article analyses the cost-effectiveness of 4 alternative gestational diabetes mellitus (GDM) screening strategies in Norway: universal screening, current (broad) screening, high-risk screening, and no screening.The current Norwegian screening recommendations were considered inefficient under all analyses.The most cost-effective screening strategy ranged from no screening to universal screening depending on the source and inclusion of GDM treatment effects on later maternal diabetes and perinatal death.The parameters related to later maternal diabetes and perinatal death accounted for most of the decision uncertainty.

Vaccination and screening strategies to accelerate cervical cancer elimination in Norway: a model-based analysis

BACKGROUND

Experts have proposed an 'EVEN FASTER' concept targeting age-groups maintaining circulation of human papillomavirus (HPV). We explored effects of the vaccination component of these proposals compared with cervical cancer (CC) screening-based interventions on age-standardized incidence rate (ASR) and CC elimination (<4 cases/100,000) timing in Norway.

METHODS

We used a model-based approach to evaluate HPV vaccination and CC screening scenarios compared with a status-quo scenario reflecting previous vaccination and screening. For cohorts ages 25-30 years, we examined 6 vaccination scenarios that incrementally increased vaccination coverage from current cohort-specific rates. Each vaccination scenario was coupled with three screening strategies that varied screening frequency. Additionally, we included 4 scenarios that alternatively increased screening adherence. Population- and cohort-level outcomes included ASR, lifetime risk of CC, and colposcopy referrals.

RESULTS

Several vaccination strategies coupled with de-intensified screening frequencies lowered ASR, but did not accelerate CC elimination. Alternative strategies that increased screening adherence could both accelerate elimination and improve ASR.

CONCLUSIONS

The vaccination component of an 'EVEN FASTER' campaign is unlikely to accelerate CC elimination in Norway but may reduce population-level ASR. Alternatively, targeting under- and never-screeners may both eliminate CC faster and lead to greater health benefits compared with vaccination-based interventions we considered.

A Guide to an Iterative Approach to Model-Based Decision Making in Health and Medicine: An Iterative Decision-Making Framework

Decision makers frequently face decisions about optimal resource allocation. A model-based economic evaluation can be used to guide decision makers in their choices by systematically evaluating the magnitude of expected health effects and costs of decision options and by making trade-offs explicit. We provide a guide to an iterative approach to the medical decision-making process by following a coherent framework, and outline the overarching iterative steps of model-based decision making. We systematized the framework by performing three steps. First, we compiled the existing guidelines provided by the ISPOR-SMDM Modeling Good Research Practices Task Force, and the ISPOR Value of Information Task Force. Second, we identified other previous work related to frameworks and guidelines for model-based decision analyses through a literature search in PubMed. Third, we assessed the role of the evidence and iterative process in decision making and formalized key steps in a model-based decision-making framework. We provide guidance on an iterative approach to medical decision making by applying the compiled iterative model-based decision-making framework. The framework formally combines the decision problem conceptualization (Part I), the model conceptualization and development (Part II), and the process of model-based decision analysis (Part III). Following the overarching steps of the framework ensures compliance to the principles of evidence-based medicine and regular updates of the evidence, given that value of information analysis represents an essential component of model-based decision analysis in the framework. Following the provided guide and the steps outlined in the framework can help inform various health care decisions, and therefore it has the potential to improve decision making.

Cost-effectiveness of primary human papillomavirus triage approaches among vaccinated women in Norway: A model-based analysis

As Norway considers revising triage approaches following their first adolescent cohort with human papillomavirus (HPV) vaccination entering the cervical cancer screening program, we analyzed the health impact and cost-effectiveness of alternative primary HPV triage approaches for women initiating cervical cancer screening in 2023. We used a multimodeling approach that captured HPV transmission and cervical carcinogenesis to evaluate the health benefits, harms and cost-effectiveness of alternative extended genotyping and age-based triage strategies under five-yearly primary HPV testing (including the status-quo screening strategy in Norway) for women born in 1998 (ie, age 25 in 2023). We examined 35 strategies that varied alternative groupings of high-risk HPV genotypes ("high-risk" genotypes; "medium-risk" genotypes or "intermediate-risk" genotypes), number and types of HPV included in each group, management of HPV-positive women to direct colposcopy or active surveillance, wait time for re-testing and age at which the HPV triage algorithm switched from less to more intensive strategies. Given the range of benchmarks for severity-specific cost-effectiveness thresholds in Norway, we found that the preferred strategy for vaccinated women aged 25 years in 2023 involved an age-based switch from a less to more intensive follow-up algorithm at age 30 or 35 years with HPV-16/18 genotypes in the "high-risk" group. The two potentially cost-effective strategies could reduce the number of colposcopies compared to current guidelines and simultaneously improve health benefits. Using age to guide primary HPV triage, paired with selective HPV genotype and follow-up time for re-testing, could improve both the cervical cancer program effectiveness and efficiency.

Adapting a model of cervical carcinogenesis to self-identified Black women to evaluate racial disparities in the United States

BACKGROUND

Self-identified Black women in the United States have higher cervical cancer incidence and mortality than the general population, but these differences have not been clearly attributed across described cancer care inequities.

METHODS

A previously established microsimulation model of cervical cancer was adapted to reflect demographic, screening, and survival data for Black US women and compared with a model reflecting data for all US women. Each model input with stratified data (all-cause mortality, hysterectomy rates, screening frequency, screening modality, follow-up, and cancer survival) was sequentially replaced with Black-race specific data to arrive at a fully specified model reflecting Black women. At each step, we estimated the relative contribution of inputs to observed disparities.

RESULTS

Estimated (hysterectomy-adjusted) cervical cancer incidence was 8.6 per 100 000 in the all-race model vs 10.8 per 100 000 in the Black-race model (relative risk [RR] = 1.24, range = 1.23-1.27). Estimated all-race cervical cancer mortality was 2.9 per 100 000 vs 5.5 per 100 000 in the Black-race model (RR = 1.92, range = 1.85-2.00). We found the largest contributors of incidence disparities were follow-up from positive screening results (47.3% of the total disparity) and screening frequency (32.7%). For mortality disparities, the largest contributor was cancer survival differences (70.1%) followed by screening follow-up (12.7%).

CONCLUSION

To reduce disparities in cervical cancer incidence and mortality, it is important to understand and address differences in care access and quality across the continuum of care. Focusing on the practices and policies that drive differences in treatment and follow-up from cervical abnormalities may have the highest impact.

Global impact and cost-effectiveness of one-dose versus two-dose human papillomavirus vaccination schedules: a comparative modelling analysis

BACKGROUND

To eliminate cervical cancer as a public health problem, the World Health Organization had recommended routine vaccination of adolescent girls with two doses of the human papillomavirus (HPV) vaccine before sexual initiation. However, many countries have yet to implement HPV vaccination because of financial or logistical barriers to delivering two doses outside the infant immunisation programme.

METHODS

Using three independent HPV transmission models, we estimated the long-term health benefits and cost-effectiveness of one-dose versus two-dose HPV vaccination, in 188 countries, under scenarios in which one dose of the vaccine gives either a shorter duration of full protection (20 or 30 years) or lifelong protection but lower vaccine efficacy (e.g. 80%) compared to two doses. We simulated routine vaccination with the 9-valent HPV vaccine in 10-year-old girls at 80% coverage for the years 2021-2120, with a 1-year catch-up campaign up to age 14 at 80% coverage in the first year of the programme.

RESULTS

Over the years 2021-2120, one-dose vaccination at 80% coverage was projected to avert 115.2 million (range of medians: 85.1-130.4) and 146.8 million (114.1-161.6) cervical cancers assuming one dose of the vaccine confers 20 and 30 years of protection, respectively. Should one dose of the vaccine provide lifelong protection at 80% vaccine efficacy, 147.8 million (140.6-169.7) cervical cancer cases could be prevented. If protection wanes after 20 years, 65 to 889 additional girls would need to be vaccinated with the second dose to prevent one cervical cancer, depending on the epidemiological profiles of the country. Across all income groups, the threshold cost for the second dose was low: from 1.59 (0.14-3.82) USD in low-income countries to 44.83 (3.75-85.64) USD in high-income countries, assuming one dose confers 30-year protection.

CONCLUSIONS

Results were consistent across the three independent models and suggest that one-dose vaccination has similar health benefits to a two-dose programme while simplifying vaccine delivery, reducing costs, and alleviating vaccine supply constraints. The second dose may become cost-effective if there is a shorter duration of protection from one dose, cheaper vaccine and vaccination delivery strategies, and high burden of cervical cancer.

Designing Guidelines for Those Who Do Not Follow Them: The Impact of Adherence Assumptions on Optimal Screening Guidelines

OBJECTIVES

Model-based cost-effectiveness analyses can inform decisions about screening guidelines by quantifying consequences of alternative algorithms. Although actual screening adherence is imperfect, incorporating nonadherence into analyses that aim to determine optimal screening may affect the policy recommendations. We evaluated the impact of nonadherence assumptions on the optimal cervical cancer screening in Norway.

METHODS

We used a microsimulation model of cervical carcinogenesis to project the long-term health and economic outcomes under alternative screening algorithms and adherence patterns. We compared 18 algorithms involving primary human papillomavirus testing (5-yearly) that varied follow-up management of different human papillomavirus results. We considered 12 adherence scenarios: perfect adherence, 8 high- and low-coverage "random-complier" scenarios, and 3 "systematic-complier" scenarios that reflect conditional screening behavior over a lifetime. We calculated incremental cost-effectiveness ratios and considered a strategy with the highest incremental cost-effectiveness ratio < 55 000 US dollars/quality-adjusted life-year as "optimal."

RESULTS

Under perfect adherence, the least intensive screening strategy was optimal; in contrast, assuming any nonadherence resulted in a more intensive optimal strategy. Accounting for lower adherence resulted in both lower costs and health benefits, which allowed for a more intensive strategy to be considered optimal, but more harms for women who screen according to guidelines (ie, up to 41% more colposcopies when comparing the optimal strategy in the lowest-adherence scenario with the optimal strategy under perfect adherence).

CONCLUSIONS

Assuming nonadherence in analyses designed to inform national guidelines may lead to a relatively more intensive recommendation. Designing guidelines for those who do not adhere to them may lead to over-screening of those who do.

Upper age-limits for US male HPV-vaccination for oropharyngeal cancer prevention: A microsimulation-based modeling study

BACKGROUND

HPV-positive oropharyngeal cancer is the most common HPV-associated cancer in the United States. The age at acquisition of oral HPV infections that cause oropharyngeal cancer (causal infections) is unknown; consequently, the benefit of vaccination of US men aged 27-45 remains uncertain.

METHODS

We developed a microsimulation-based, individual-level, state-transition model of oral HPV16 and HPV16-positive oropharyngeal cancer among heterosexual US men aged 15-84 years, calibrated to population-level data. We estimated the benefit of vaccination of men aged 27-45 for prevention of oropharyngeal cancer, while accounting for direct- and indirect/herd-effects of male and female vaccination.

RESULTS

In the absence of vaccination, most (70%) causal oral HPV16 infections are acquired by age 26, and 29% are acquired between ages 27-45. Among men aged 15-45 in 2021 (1976-2006 birth cohorts), status-quo vaccination of men through age 26 is estimated to prevent 95% of 153,450 vaccine-preventable cancers. Assuming 100% vaccination in 2021, extending the upper age-limit to 30, 35, 40, or 45 for men aged 27-45 (1976-1994 cohorts) is estimated to yield small benefit (3.0%, 4.2%, 5.1%, and 5.6% additional cancers prevented, respectively). Importantly, status-quo vaccination of men through age 26 is predicted to result in notable declines in HPV16-positive oropharyngeal cancer incidence in young men by 2035 (51% and 24% declines at ages 40-44 and 45-49, respectively) and noticeable declines (12%) overall by 2045.

CONCLUSION

Most causal oral HPV16 infections in US men are acquired by age 26, underscoring limited benefit from vaccination of men aged 27-45 for prevention of HPV16-positive oropharyngeal cancers.

The cost-effectiveness of opt-in and send-to-all HPV self-sampling among long-term non-attenders to cervical cancer screening in Norway: The Equalscreen randomized controlled trial

OBJECTIVE

We assessed the cost-effectiveness of mailing a human papillomavirus self-sampling (HPV-ss) kit, directly or via invitation to order, compared with mailing reminder letters among long-term non-attenders in Norway.

METHODS

We conducted a secondary analysis using the Equalscreen study data with 6000 women aged 35-69 years who had not screened in 10+ years. Participants were equally randomized into three arms: reminder letter (control); invitation to order HPV-ss kit (opt-in); directly mailed HPV-ss kit (send-to-all). Cost-effectiveness (2020 Great British Pounds (GBP)) was estimated using incremental cost-effectiveness ratios (ICERs) per additional screened woman, and per additional cervical intraepithelial neoplasia grade 2 or worse (CIN2+) from extended and direct healthcare perspectives.

RESULTS

Participation, CIN2+ detection, and total screening costs were highest in the send-to-all arm, followed by the opt-in and control arms. Non-histological physician appointments contributed to 67% of the total costs in the control arm and ≤ 31% in the self-sampling arms. From an expanded healthcare perspective, the ICERs were 135 GBP and 169 GBP per additional screened woman, and 2864 GBP and 4165 GBP per additional CIN2+ detected for the opt-in and send-to-all, respectively.

CONCLUSIONS

Opt-in and send-to-all self-sampling were more effective and, depending on willingness-to-pay, may be considered cost-effective alternatives to improve screening attendance in Norway.

Now or later: Health impacts of delaying single-dose HPV vaccine implementation in a high-burden setting

We aimed to quantify the health impact of immediate introduction of a single-dose human papillomavirus (HPV) vaccination program in a high-burden setting, as waiting until forthcoming trials are completed to implement single-dose HPV vaccination may result in health losses, particularly for cohorts who would age-out of vaccination eligibility. Two mathematical models fitted to a high-burden setting projected cervical cancer incidence rates associated with (a) immediate implementation of one-dose HPV vaccination vs (b) waiting 5 years for evidence from randomized trials to determine if one- or two-doses should be implemented. We conducted analyses assuming a single dose was either noninferior or inferior to two doses. The models projected that immediate implementation of a noninferior single-dose vaccine led to a 7.2% to 9.6% increase in cancers averted between 2021 to 2120, compared to waiting 5 years. Health benefits remained greater with immediate implementation despite an inferior single-dose efficacy (80%), but revaccination of one-dose recipients became more important assuming vaccine waning. Under most circumstances, immediate vaccination avoided health losses for those aging out of vaccine eligibility, leading to greater health benefits than waiting for more information in 5 years.

A model-based analysis of the health impacts of COVID-19 disruptions to primary cervical screening by time since last screen for current and future disruptions

We evaluated how temporary disruptions to primary cervical cancer (CC) screening services may differentially impact women due to heterogeneity in their screening history and test modality. We used three CC models to project the short- and long-term health impacts assuming an underlying primary screening frequency (i.e., 1, 3, 5, or 10 yearly) under three alternative COVID-19-related screening disruption scenarios (i.e., 1-, 2-, or 5-year delay) versus no delay in the context of both cytology-based and human papillomavirus (HPV)-based screening. Models projected a relative increase in symptomatically detected cancer cases during a 1-year delay period that was 38% higher (Policy1-Cervix), 80% higher (Harvard), and 170% higher (MISCAN-Cervix) for underscreened women whose last cytology screen was 5 years prior to the disruption period compared with guidelines-compliant women (i.e., last screen 3 years prior to disruption). Over a woman's lifetime, temporary COVID-19-related delays had less impact on lifetime risk of developing CC than screening frequency and test modality; however, CC risks increased disproportionately the longer time had elapsed since a woman's last screen at the time of the disruption. Excess risks for a given delay period were generally lower for HPV-based screeners than for cytology-based screeners. Our independent models predicted that the main drivers of CC risk were screening frequency and screening modality, and the overall impact of disruptions from the pandemic on CC outcomes may be small. However, screening disruptions disproportionately affect underscreened women, underpinning the importance of reaching such women as a critical area of focus, regardless of temporary disruptions.

Transition from Laser to Intravitreal Injections for Diabetic Retinopathy: Hospital Utilization and Costs from an Extended Healthcare Perspective

PURPOSE

To describe the trends in hospital utilization and economic outcomes associated with the transition from laser to intravitreal injection (IVI) therapy for diabetic retinopathy (DR) at Oslo University Hospital (OUH), which provides the largest retina service in Norway.

METHODS

This descriptive study analyzed hospital administrative data and determined the average utilization and treatment proportions of laser therapy, IVIs and vitrectomy for each patient per year. The Chi-square test was used to compare resource use between treatment groups. From an extended healthcare perspective, the annual cost per patient was calculated using Norwegian tariff data from 2020 and the National Medication Price Registry for patients seen between 2010 and 2018. Bootstrapping was performed to generate 95% confidence intervals for the cost per patient per year.

RESULTS

Among the 1838 (41% female) patients treated for DR between 2005 and 2018, OUH provided on average 1.09 laser treatments per DR patient and 0.54 vitrectomies per DR patient in 2005, whose utilization declined to 0.54 and 0.05 treatments per DR patient, respectively, by 2018. Laser treatments declined from 64% to 10%, while vitrectomies declined from 32% to 1%. In contrast, IVI treatments increased from 4.5% to 89% of the total share, representing an average increase, from 0.08 injections per patient in 2005 to 4.73 injections per patient in 2018. Both the increasing number of DR patients and the shift in the type of treatment increased the economic costs of treating DR from a total of EUR 0.605 million (EUR 2935 per patient) in 2010 to EUR 2.240 million (EUR 3665 per patient) in 2018, with IVIs contributing considerably to these costs.

CONCLUSIONS

Despite the decline in the use of vitrectomies, the transition from laser to IVI therapy for DR increased the healthcare resource utilization and economic costs of its treatment over the observed time. A main cost driver was the need for long-term IVIs, in addition to the drug cost itself. Trade-offs can be achieved through effective alternative IVI delivery or appropriate drug choice that balances patient needs with the economic burden of treating DR.

Health impacts of COVID-19 disruptions to primary cervical screening by time since last screen: A model-based analysis for current and future disruptions

Background

We evaluated how temporary disruptions to primary cervical cancer (CC) screening services may differentially impact women due to heterogeneity in their screening history and test modality.

Methods

We used three CC models to project the short- and long-term health impacts assuming an underlying primary screening frequency (i.e., 1, 3, 5, or 10 yearly) under three alternative COVID-19-related screening disruption scenarios (i.e., 1-, 2- or 5-year delay) versus no delay, in the context of both cytology-based and HPV-based screening.

Results

Models projected a relative increase in symptomatically-detected cancer cases during a 1-year delay period that was 38% higher (Policy1-Cervix), 80% higher (Harvard) and 170% higher (MISCAN-Cervix) for under-screened women whose last cytology screen was 5 years prior to the disruption period compared with guidelines-compliant women (i.e., last screen three years prior to disruption). Over a woman's lifetime, temporary COVID-19-related delays had less impact on lifetime risk of developing CC than screening frequency and test modality; however, CC risks increased disproportionately the longer time had elapsed since a woman's last screen at the time of the disruption. Excess risks for a given delay period were generally lower for HPV-based screeners than for cytology-based screeners.

Conclusions

Our independent models predicted that the main drivers of CC risk were screening frequency and screening modality, and the overall impact of disruptions from the pandemic on CC outcomes may be small. However, screening disruptions disproportionately affect under-screened women, underpinning the importance of reaching such women as a critical area of focus, regardless of temporary disruptions.

Funding

This study was supported by funding from the National Cancer Institute (U01CA199334). The contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute. Megan A Smith receives salary support from the National Health and Medical Research Council, Australia (APP1159491) and Cancer Institute NSW (ECF181561). Matejka Rebolj is funded by Cancer Research UK (reference: C8162/A27047). James O'Mahony is funded by Ireland's Health Research Board (EIA2017054). Karen Canfell receives salary support from the National Health and Medical Research Council, Australia (APP1194679). Emily A. Burger receives salary support from the Norwegian Cancer Society.

Identifying a Single Optimal Integrated Cervical Cancer Prevention Policy in Norway: A Cost-Effectiveness Analysis

BACKGROUND

Interventions targeting the same disease but at different points along the disease continuum (e.g., screening and vaccination to prevent cervical cancer [CC]) are often evaluated in isolation, which can affect cost-effectiveness profiles and policy conclusions. We evaluated nonavalent human papillomavirus (HPV) vaccine (9vHPV) compared with bivalent HPV vaccine (2vHPV) alongside deintensified screening intervals for a vaccinated birth cohort to inform a single optimal integrated CC prevention policy.

METHODS

Using a multimodeling approach, we evaluated the health and economic impacts of alternative CC screening strategies for a Norwegian birth cohort eligible for HPV vaccination in 2021 assuming they received 1) 2vHPV or 2) 9vHPV. We conducted 1) a restricted analysis that evaluated the optimal HPV vaccine under current screening guidelines; and 2) a comprehensive analysis including alternative screening and vaccination strategy combinations. We calculated incremental cost-effectiveness ratios (ICERs) and evaluated them according to different cost-effectiveness thresholds.

RESULTS

Assuming a cost-effectiveness threshold of $40,000 per quality-adjusted life year (QALY) gained, we found that, while holding screening intensity fixed, switching the routine vaccination program in Norway from 2vHPV to 9vHPV would not be considered cost-effective (ICER of $132,700 per QALY gained). However, when allowing for varying intensities of CC screening, we found that switching to 9vHPV would be cost-effective compared with 2vHPV under an alternative threshold of $55,000 per QALY gained, if coupled with reductions in the number of lifetime screens.

CONCLUSIONS

Our analysis highlights the importance of evaluating the full potential policy landscape for country-level decision makers considering policy adoption, including nonindependent primary and secondary prevention efforts, to draw appropriate conclusions and avoid sub-optimal outcomes.

HIGHLIGHTS

Without evaluating the full potential policy landscape, including primary and secondary prevention efforts, country-level decision makers may not be able to draw appropriate policy conclusions, resulting in suboptimal outcomes.An applied example from cervical cancer prevention in Norway compared a restricted analysis of current screening guidelines to a comprehensive analysis including alternative screening and vaccination strategy combinations.We found that a switch from bivalent to nonavalent human papillomavirus vaccine would be considered cost-effective in Norway if coupled with reductions in the number of lifetime screens compared with the current screening strategy.A comprehensive analysis that considers how different types of interventions along the disease continuum affect each other will be critical for decision makers interpreting cost-effectiveness analysis results.

Switching clinic-based cervical cancer screening programs to human papillomavirus self-sampling: A cost-effectiveness analysis of vaccinated and unvaccinated Norwegian women

Several countries have implemented primary human papillomavirus (HPV) testing for cervical cancer screening. HPV testing enables home-based, self-collected sampling (self-sampling), which provides similar diagnostic accuracy as clinician-collected samples. We evaluated the impact and cost-effectiveness of switching an entire organized screening program to primary HPV self-sampling among cohorts of HPV vaccinated and unvaccinated Norwegian women. We conducted a model-based analysis to project long-term health and economic outcomes for birth cohorts with different HPV vaccine exposure, that is, preadolescent vaccination (2000- and 2008-cohorts), multiage cohort vaccination (1991-cohort) or no vaccination (1985-cohort). We compared the cost-effectiveness of switching current guidelines with clinician-collected HPV testing to HPV self-sampling for these cohorts and considered an additional 44 strategies involving either HPV self-sampling or clinician-collected HPV testing at different screening frequencies for the 2000- and 2008-cohorts. Given Norwegian benchmarks for cost-effectiveness, we considered a strategy with an additional cost per quality-adjusted life-year below $55 000 as cost-effective. HPV self-sampling strategies considerably reduced screening costs (ie, by 24%-40% across cohorts and alternative strategies) and were more cost-effective than clinician-collected HPV testing. For cohorts offered preadolescent vaccination, cost-effective strategies involved HPV self-sampling three times (2000-cohort) and twice (2008-cohort) per lifetime. In conclusion, we found that switching from clinician-collected to self-collected HPV testing in cervical screening may be cost-effective among both highly vaccinated and unvaccinated cohorts of Norwegian women.

Impact of Delaying Effective and Cost-Effective Policy Decisions: An Example From Cervical Cancer Prevention in Norway

Introduction. Delayed implementation of evidence-driven interventions has consequences that can be formally evaluated. In Norway, programs to prevent cervical cancer (CC)—screening and treatment of precancerous lesions and prophylactic vaccination against human papillomavirus (HPV) infection—have been implemented, but each encountered delays in policy implementation. To examine the effect of these delays, we project the outcomes that would have been achieved with timely implementation of two policy changes compared with the de facto delays in implementation (in Norway). Methods. We used a multimodeling approach that combined HPV transmission and cervical carcinogenesis to estimate the health outcomes and timeline for CC elimination associated with the implementation of two CC prevention policy decisions: a multicohort vaccination program of women up to age 26 years with bivalent vaccine in 2009 compared with actual “delayed” implementation in 2016, and a switch from cytology to primary HPV-based testing in 2015 compared with “delayed” rollout in 2020. Results. Timely implementation of two policy changes compared with current Norwegian prevention policy timeline could have averted approximately 970 additional cases (range of top 10 sets: 830–1060) and accelerated the CC elimination timeline by around 4 years (from 2039 to 2035). Conclusions. If delaying implementation of effective and cost-effective interventions is being considered, the decision-making process should include quantitative analyses on the effects of delays.

Potential effectiveness of a therapeutic HPV intervention campaign in Uganda

Cervical cancer is a major source of morbidity and mortality in Uganda. In addition to prophylactic HPV vaccination, secondary prevention strategies are needed to reduce cancer burden. We evaluated the potential cancer reductions associated with a hypothetical single-contact therapeutic HPV intervention-with 70% coverage and variable efficacy [30%-100%]-using a three-stage HPV modeling framework reflecting HPV and cervical cancer burden in Uganda. In the reference case, we assumed prophylactic preadolescent HPV vaccination starting in 2020 with 70% coverage. A one-time therapeutic intervention targeting 35-year-old women in 2025 (not age-eligible for prophylactic vaccination) averted 1801 cervical cancers per 100 000 women over their lifetime (100% efficacy) or 533 cancers per 100 000 (30% efficacy). Benefits were considerably smaller in birth cohorts eligible for prophylactic HPV vaccination (768 cases averted per 100 000 at 100% efficacy). Evaluating the population-level impact over 40 years, we found introduction of a therapeutic intervention in 2025 with 100% efficacy targeted annually to 30-year-old women averted 139 000 incident cervical cancers in Uganda. This benefit was greatly reduced if efficacy was lower (30% efficacy; 41 000 cases averted), introduction was delayed (2040 introduction; 72 000 cases averted) or both (22 000 cases averted). We demonstrate the potential benefits of a single-contact HPV therapeutic intervention in a low-income setting, but show the importance of high therapeutic efficacy and early introduction timing relative to existing prophylactic programs. Reduced benefits from a less efficacious intervention may be somewhat offset if available within a shorter time frame.

Impact of disruptions and recovery for established cervical screening programs across a range of high-income country program designs, using COVID-19 as an example: A modelled analysis

COVID-19 has disrupted cervical screening in several countries, due to a range of policy-, health-service and participant-related factors. Using three well-established models of cervical cancer natural history adapted to simulate screening across four countries, we compared the impact of a range of standardised screening disruption scenarios in four countries that vary in their cervical cancer prevention programs. All scenarios assumed a 6- or 12-month disruption followed by a rapid catch-up of missed screens. Cervical screening disruptions could increase cervical cancer cases by up to 5-6%. In all settings, more than 60% of the excess cancer burden due to disruptions are likely to have occurred in women aged less than 50 years in 2020, including settings where women in their 30s have previously been offered HPV vaccination. Approximately 15-30% of cancers predicted to result from disruptions could be prevented by maintaining colposcopy and precancer treatment services during any disruption period. Disruptions to primary screening had greater adverse effects in situations where women due to attend for screening in 2020 had cytology (vs. HPV) as their previous primary test. Rapid catch-up would dramatically increase demand for HPV tests in 2021, which it may not be feasible to meet because of competing demands on the testing machines and reagents due to COVID tests. These findings can inform future prioritisation strategies for catch-up that balance potential constraints on resourcing with clinical need.

Providing more balanced information on the harms and benefits of cervical cancer screening: A randomized survey among US and Norwegian women

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Additional information did not impact intentions to participate in CC screening.

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Additional information increased uncertainty to seek precancer treatment in Norway.

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Women reported strong system-specific preferences for sources of information.

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Having a prior Pap-test was an important predictor of intentions-to-participate.

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Socioeconomic factors influenced follow-up intentions in the U.S. but not in Norway.

We aimed to identify how additional information about benefits and harms of cervical cancer (CC) screening impacted intention to participate in screening, what type of information on harms women preferred receiving, from whom, and whether it differed between two national healthcare settings. We conducted a survey that randomized screen-eligible women in the United States (n = 1084) and Norway (n = 1060) into four groups according to the timing of introducing additional information. We found that additional information did not significantly impact stated intentions-to-participate in screening or follow-up testing in either country; however, the proportion of Norwegian women stating uncertainty about seeking precancer treatment increased from 7.9% to 14.3% (p = 0.012). Women reported strong system-specific preferences for sources of information: Norwegians (59%) preferred it come from a national public health agency while Americans (59%) preferred it come from a specialist care provider. Regression models revealed having a prior Pap-test was the most important predictor of intentions-to-participate in both countries, while having lower income reduced the probabilities of intentions-to-follow-up and seek precancer treatment among U.S. women. These results suggest that additional information on harms is unlikely to reduce participation in CC screening but could increase decision uncertainty to seek treatment. Providing unbiased information would improve on the ethical principle of respect for autonomy and self-determination. However, the clinical impact of additional information on women’s understanding of the trade-offs involved with CC screening should be investigated. Future studies should also consider country-specific socioeconomic barriers to screening if communication re-design initiatives aim to improve CC screening participation.

Estimating the Natural History of Cervical Carcinogenesis Using Simulation Models: A CISNET Comparative Analysis

BACKGROUND

The natural history of human papillomavirus (HPV)-induced cervical cancer (CC) is not directly observable, yet the age of HPV acquisition and duration of preclinical disease (dwell time) influences the effectiveness of alternative preventive policies. We performed a Cancer Intervention and Surveillance Modeling Network (CISNET) comparative modeling analysis to characterize the age of acquisition of cancer-causing HPV infections and implied dwell times for distinct phases of cervical carcinogenesis.

METHODS

Using four CISNET-cervical models with varying underlying structures but fit to common US epidemiological data, we estimated the age of acquisition of causal HPV infections and dwell times associated with three phases of cancer development: HPV, high-grade precancer, and cancer sojourn time. We stratified these estimates by HPV genotype under both natural history and CC screening scenarios, because screening prevents cancer development that affects the mix of detected cancers.

RESULTS

The median time from HPV acquisition to cancer detection ranged from 17.5 to 26.0 years across the four models. Three models projected that 50% of unscreened women acquired their causal HPV infection between ages 19 and 23 years, whereas one model projected these infections occurred later (age 34 years). In the context of imperfect compliance with US screening guidelines, the median age of causal infection was 4.4-15.9 years later compared with model projections in the absence of screening.

CONCLUSIONS

These validated CISNET-CC models, which reflect some uncertainty in the development of CC, elucidate important drivers of HPV vaccination and CC screening policies and emphasize the value of comparative modeling when evaluating public health policies.

Impact of COVID-19-related care disruptions on cervical cancer screening in the United States

OBJECTIVES

To quantify the secondary impacts of the COVID-19 pandemic disruptions to cervical cancer screening in the United States, stratified by step in the screening process and primary test modality, on cervical cancer burden.

METHODS

We conducted a comparative model-based analysis using three independent NCI Cancer Intervention and Surveillance Modeling Network cervical models to quantify the impact of eight alternative COVID-19-related screening disruption scenarios compared to a scenario of no disruptions. Scenarios varied by the duration of the disruption (6 or 24 months), steps in the screening process being disrupted (primary screening, surveillance, colposcopy, excisional treatment), and primary screening modality (cytology alone or cytology plus human papillomavirus "cotesting").

RESULTS

The models consistently showed that COVID-19-related disruptions yield small net increases in cervical cancer cases by 2027, which are greater for women previously screened with cytology compared with cotesting. When disruptions affected all four steps in the screening process under cytology-based screening, there were an additional 5-7 and 38-45 cases per one million screened for 6- and 24-month disruptions, respectively. In contrast, under cotesting, there were additional 4-5 and 35-45 cases per one million screened for 6- and 24-month disruptions, respectively. The majority (58-79%) of the projected increases in cases under cotesting were due to disruptions to surveillance, colposcopies, or excisional treatment, rather than to primary screening.

CONCLUSIONS

Women in need of surveillance, colposcopies, or excisional treatment, or whose last primary screen did not involve human papillomavirus testing, may comprise priority groups for reintroductions.

Human papillomavirus vaccination for adults aged 30 to 45 years in the United States: A cost-effectiveness analysis

BACKGROUND

A nonavalent human papillomavirus (HPV) vaccine has been licensed for use in women and men up to age 45 years in the United States. The cost-effectiveness of HPV vaccination for women and men aged 30 to 45 years in the context of cervical cancer screening practice was evaluated to inform national guidelines.

METHODS AND FINDINGS

We utilized 2 independent HPV microsimulation models to evaluate the cost-effectiveness of extending the upper age limit of HPV vaccination in women (from age 26 years) and men (from age 21 years) up to age 30, 35, 40, or 45 years. The models were empirically calibrated to reflect the burden of HPV and related cancers in the US population and used standardized inputs regarding historical and future vaccination uptake, vaccine efficacy, cervical cancer screening, and costs. Disease outcomes included cervical, anal, oropharyngeal, vulvar, vaginal, and penile cancers, as well as genital warts. Both models projected higher costs and greater health benefits as the upper age limit of HPV vaccination increased. Strategies of vaccinating females and males up to ages 30, 35, and 40 years were found to be less cost-effective than vaccinating up to age 45 years, which had an incremental cost-effectiveness ratio (ICER) greater than a commonly accepted upper threshold of $200,000 per quality-adjusted life year (QALY) gained. When including all HPV-related outcomes, the ICER for vaccinating up to age 45 years ranged from $315,700 to $440,600 per QALY gained. Assumptions regarding cervical screening compliance, vaccine costs, and the natural history of noncervical HPV-related cancers had major impacts on the cost-effectiveness of the vaccination strategies. Key limitations of the study were related to uncertainties in the data used to inform the models, including the timing of vaccine impact on noncervical cancers and vaccine efficacy at older ages.

CONCLUSIONS

Our results from 2 independent models suggest that HPV vaccination for adult women and men aged 30 to 45 years is unlikely to represent good value for money in the US.

Impact and cost-effectiveness of strategies to accelerate cervical cancer elimination: A model-based analysis

Following the global call for action by the World Health Organization to eliminate cervical cancer (CC), we evaluated how each CC policy decision in Norway influenced the timing of CC elimination, and whether introducing nonavalent human papillomavirus (HPV) vaccine would accelerate elimination timing and be cost-effective. We used a multi-modeling approach that captured HPV transmission and cervical carcinogenesis to estimate the CC incidence associated with six past and future CC prevention policy decisions compared with a pre-vaccination scenario involving 3-yearly cytology-based screening. Scenarios examined the introduction of routine HPV vaccination of 12-year-old girls with quadrivalent vaccine in 2009, a temporary catch-up program for females aged up to 26 years in 2016-2018 with bivalent vaccine, the universal switch to bivalent vaccine in 2017, expansion to include 12-year-old boys in 2018, the switch from cytology- to HPV-based screening for women aged 34-69 in 2020, and the potential switch to nonavalent vaccine in 2021. Introducing routine female vaccination in 2009 enabled elimination to be achieved by 2056 and prevented 17,300 cases. Cumulatively, subsequent policy decisions accelerated elimination to 2039. According to our modeling assumptions, switching to the nonavalent vaccine would not be considered 'good value for money' at relevant cost-effectiveness thresholds in Norway unless the incremental cost was $19 per dose or less (range: $17-24) compared to the bivalent vaccine. CC control policies implemented over the last decade in Norway may have accelerated the timeframe to elimination by more than 17 years and prevented over 23,800 cases by 2110.

Cost-effectiveness of cervical cancer screening with primary HPV testing for unvaccinated women in Sweden

BACKGROUND

Sweden revised their cervical cancer screening program in 2017 to include cytology-based screening for women aged 23-29 years and primary human papillomavirus (HPV) testing for women aged 30-64 years; however, alternative strategies may be preferred. To inform cervical cancer prevention policies for unvaccinated women, we evaluated the cost-effectiveness of alternative screening strategies, including the current Swedish guidelines.

METHODS

We adapted a mathematical simulation model of HPV and cervical cancer to the Swedish context using primary epidemiologic data. We compared the cost-effectiveness of alternative screening strategies that varied by the age to start screening, the age to switch from cytology to HPV testing, HPV strategies not preceded by cytology, screening frequency, and management of HPV-positive/cytology-negative women.

RESULTS

We found that the current Swedish guidelines were more costly and less effective than alternative primary HPV-based strategies. All cost-efficient strategies involved primary HPV testing not preceded by cytology for younger women. Given a cost-effectiveness threshold of €85,619 per quality-adjusted life year gained, the optimal strategy involved 5-yearly primary HPV-based screening for women aged 23-50 years and 10-yearly HPV-based screening for women older than age 50 years.

CONCLUSIONS

Primary screening based on HPV alone may be considered for unvaccinated women for those countries with similar HPV burdens.

Choosing the optimal HPV vaccine: The health impact and economic value of the nonavalent and bivalent HPV vaccines in 48 Gavi-eligible countries

The human papillomavirus (HPV) vaccines may provide some level of cross-protection against high-risk HPV genotypes not directly targeted by the vaccines. We evaluated the long-term health and economic impacts of routine HPV vaccination using either the nonavalent HPV vaccine or the bivalent HPV vaccine in the context of 48 Gavi-eligible countries. We used a multi-modeling approach to compare the bivalent with or without cross-protection and the nonavalent HPV vaccine. The optimal, that is, most cost-effective, vaccine was the vaccine with an incremental cost-effectiveness ratio below the per-capita gross domestic product (GDP) for each country. By 2100 and assuming 70% HPV vaccination coverage, a bivalent vaccine without cross-protection, a bivalent vaccine with favorable cross-protection and the nonavalent vaccine were projected to avert 14.9, 17.2 and 18.5 million cumulative cases of cervical cancer across all 48 Gavi-eligible countries, respectively. The relative value of the bivalent vaccine compared to the nonavalent vaccine increased assuming a bivalent vaccine conferred high cross-protection. For example, assuming a cost-effectiveness threshold of per-capita GDP, the nonavalent vaccine was optimal in 83% (n = 40) of countries if the bivalent vaccine did not confer cross-protection; however, the proportion of countries decreased to 63% (n = 30) if the bivalent vaccine conferred high cross-protection. For lower cost-effectiveness thresholds, the bivalent vaccine was optimal in a greater proportion of countries, under both cross-protection assumptions. Although the nonavalent vaccine is projected to avert more cases of cervical cancer, the bivalent vaccine with favorable cross-protection can prevent a considerable number of cases and would be considered a high-value vaccine for many Gavi-eligible countries.

Historical and projected hysterectomy rates in the USA: Implications for future observed cervical cancer rates and evaluating prevention interventions

BACKGROUND

SEER-reported cervical cancer incidence rates reflect the total female population including women no longer at risk due to hysterectomy. Hysterectomy rates have been declining in the United States as alternative treatments have become available, which could result in an apparent increase in SEER-reported cervical cancer rates. We aimed to obtain nationally representative historical data on hysterectomy rates in USA, use trends analysis to project rates back to 1935 and forward to 2035, and then predict the impact of changing hysterectomy rates on SEER-reported cervical cancer rates.

METHODS

We performed a systematic search of Medline, Embase, Premedline, Cochrane Central databases and extracted nationally-representative hysterectomy incidence data from 1965 to 2009, including data on the number of cervix-preserving (subtotal) procedures. We then projected rates back to 1935, and forward to 2035 based on trends from joinpoint regression. These rates were then used to estimate hysterectomy prevalence out to 2035, and then to predict the impact of changing hysterectomy rates on SEER-reported cervical cancer rates to 2035. We examined alternative assumptions regarding projected hysterectomy incidence rates out to 2035, including a scenario in which rates decline no further from 2009 rates, and a scenario where rates decline at twice the baseline rate.

RESULTS

Estimated age-standardized hysterectomy incidence increased from 2.4 to 10.6 per 1000 women between 1935 and 1975. Thereafter, rates are predicted to fall to 3.9 per 1000 by 2035. Subtotal hysterectomy procedures declined from being the predominant method in 1935 to less than 12% of procedures from 1970 onwards. Consequently, holding all else constant, an increase in SEER-reported age-standardized cervical cancer incidence rates (ages 0-85+) of 9% is expected from 2009 to 2035. The predictions were minimally impacted by alternative scenarios for future hysterectomy rates.

CONCLUSIONS

Declining hysterectomy rates have implications for the interpretation of SEER-reported cervical cancer rates. A background increase in cervical cancer rates due to decreasing population hysterectomy exposure may partially offset expected decreases from recent cervical screening changes recommended by the US Preventive Services Task Force. Evaluations of new cervical cancer prevention opportunities should consider the background impact of historical and projected hysterectomy rates.

The Impact of Different Screening Model Structures on Cervical Cancer Incidence and Mortality Predictions: The Maximum Clinical Incidence Reduction (MCLIR) Methodology

Background. To interpret cervical cancer screening model results, we need to understand the influence of model structure and assumptions on cancer incidence and mortality predictions. Cervical cancer cases and deaths following screening can be attributed to 1) (precancerous or cancerous) disease that occurred after screening, 2) disease that was present but not screen detected, or 3) disease that was screen detected but not successfully treated. We examined the relative contributions of each of these using 4 Cancer Intervention and Surveillance Modeling Network (CISNET) models. Methods. The maximum clinical incidence reduction (MCLIR) method compares changes in the number of clinically detected cervical cancers and mortality among 4 scenarios: 1) no screening, 2) one-time perfect screening at age 45 that detects all existing disease and delivers perfect (i.e., 100% effective) treatment of all screen-detected disease, 3) one-time realistic-sensitivity cytological screening and perfect treatment of all screen-detected disease, and 4) one-time realistic-sensitivity cytological screening and realistic-effectiveness treatment of all screen-detected disease. Results. Predicted incidence reductions ranged from 55% to 74%, and mortality reduction ranged from 56% to 62% within 15 years of follow-up for scenario 4 across models. The proportion of deaths due to disease not detected by screening differed across the models (21%–35%), as did the failure of treatment (8%–16%) and disease occurring after screening (from 1%–6%). Conclusions. The MCLIR approach aids in the interpretation of variability across model results. We showed that the reasons why screening failed to prevent cancers and deaths differed between the models. This likely reflects uncertainty about unobservable model inputs and structures; the impact of this uncertainty on policy conclusions should be examined via comparing findings from different well-calibrated and validated model platforms.

Impact of HPV vaccination and cervical screening on cervical cancer elimination: a comparative modelling analysis in 78 low-income and lower-middle-income countries

BACKGROUND

The WHO Director-General has issued a call for action to eliminate cervical cancer as a public health problem. To help inform global efforts, we modelled potential human papillomavirus (HPV) vaccination and cervical screening scenarios in low-income and lower-middle-income countries (LMICs) to examine the feasibility and timing of elimination at different thresholds, and to estimate the number of cervical cancer cases averted on the path to elimination.

METHODS

The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC), which consists of three independent transmission-dynamic models identified by WHO according to predefined criteria, projected reductions in cervical cancer incidence over time in 78 LMICs for three standardised base-case scenarios: girls-only vaccination; girls-only vaccination and once-lifetime screening; and girls-only vaccination and twice-lifetime screening. Girls were vaccinated at age 9 years (with a catch-up to age 14 years), assuming 90% coverage and 100% lifetime protection against HPV types 16, 18, 31, 33, 45, 52, and 58. Cervical screening involved HPV testing once or twice per lifetime at ages 35 years and 45 years, with uptake increasing from 45% (2023) to 90% (2045 onwards). The elimination thresholds examined were an average age-standardised cervical cancer incidence of four or fewer cases per 100 000 women-years and ten or fewer cases per 100 000 women-years, and an 85% or greater reduction in incidence. Sensitivity analyses were done, varying vaccination and screening strategies and assumptions. We summarised results using the median (range) of model predictions.

FINDINGS

Girls-only HPV vaccination was predicted to reduce the median age-standardised cervical cancer incidence in LMICs from 19·8 (range 19·4-19·8) to 2·1 (2·0-2·6) cases per 100 000 women-years over the next century (89·4% [86·2-90·1] reduction), and to avert 61·0 million (60·5-63·0) cases during this period. Adding twice-lifetime screening reduced the incidence to 0·7 (0·6-1·6) cases per 100 000 women-years (96·7% [91·3-96·7] reduction) and averted an extra 12·1 million (9·5-13·7) cases. Girls-only vaccination was predicted to result in elimination in 60% (58-65) of LMICs based on the threshold of four or fewer cases per 100 000 women-years, in 99% (89-100) of LMICs based on the threshold of ten or fewer cases per 100 000 women-years, and in 87% (37-99) of LMICs based on the 85% or greater reduction threshold. When adding twice-lifetime screening, 100% (71-100) of LMICs reached elimination for all three thresholds. In regions in which all countries can achieve cervical cancer elimination with girls-only vaccination, elimination could occur between 2059 and 2102, depending on the threshold and region. Introducing twice-lifetime screening accelerated elimination by 11-31 years. Long-term vaccine protection was required for elimination.

INTERPRETATION

Predictions were consistent across our three models and suggest that high HPV vaccination coverage of girls can lead to cervical cancer elimination in most LMICs by the end of the century. Screening with high uptake will expedite reductions and will be necessary to eliminate cervical cancer in countries with the highest burden.

FUNDING

WHO, UNDP, UN Population Fund, UNICEF-WHO-World Bank Special Program of Research, Development and Research Training in Human Reproduction, Canadian Institute of Health Research, Fonds de recherche du Québec-Santé, Compute Canada, National Health and Medical Research Council Australia Centre for Research Excellence in Cervical Cancer Control.

Mortality impact of achieving WHO cervical cancer elimination targets: a comparative modelling analysis in 78 low-income and lower-middle-income countries

BACKGROUND

WHO is developing a global strategy towards eliminating cervical cancer as a public health problem, which proposes an elimination threshold of four cases per 100 000 women and includes 2030 triple-intervention coverage targets for scale-up of human papillomavirus (HPV) vaccination to 90%, twice-lifetime cervical screening to 70%, and treatment of pre-invasive lesions and invasive cancer to 90%. We assessed the impact of achieving the 90-70-90 triple-intervention targets on cervical cancer mortality and deaths averted over the next century. We also assessed the potential for the elimination initiative to support target 3.4 of the UN Sustainable Development Goals (SDGs)-a one-third reduction in premature mortality from non-communicable diseases by 2030.

METHODS

The WHO Cervical Cancer Elimination Modelling Consortium (CCEMC) involves three independent, dynamic models of HPV infection, cervical carcinogenesis, screening, and precancer and invasive cancer treatment. Reductions in age-standardised rates of cervical cancer mortality in 78 low-income and lower-middle-income countries (LMICs) were estimated for three core scenarios: girls-only vaccination at age 9 years with catch-up for girls aged 10-14 years; girls-only vaccination plus once-lifetime screening and cancer treatment scale-up; and girls-only vaccination plus twice-lifetime screening and cancer treatment scale-up. Vaccination was assumed to provide 100% lifetime protection against infections with HPV types 16, 18, 31, 33, 45, 52, and 58, and to scale up to 90% coverage in 2020. Cervical screening involved HPV testing at age 35 years, or at ages 35 years and 45 years, with scale-up to 45% coverage by 2023, 70% by 2030, and 90% by 2045, and we assumed that 50% of women with invasive cervical cancer would receive appropriate surgery, radiotherapy, and chemotherapy by 2023, which would increase to 90% by 2030. We summarised results using the median (range) of model predictions.

FINDINGS

In 2020, the estimated cervical cancer mortality rate across all 78 LMICs was 13·2 (range 12·9-14·1) per 100 000 women. Compared to the status quo, by 2030, vaccination alone would have minimal impact on cervical cancer mortality, leading to a 0·1% (0·1-0·5) reduction, but additionally scaling up twice-lifetime screening and cancer treatment would reduce mortality by 34·2% (23·3-37·8), averting 300 000 (300 000-400 000) deaths by 2030 (with similar results for once-lifetime screening). By 2070, scaling up vaccination alone would reduce mortality by 61·7% (61·4-66·1), averting 4·8 million (4·1-4·8) deaths. By 2070, additionally scaling up screening and cancer treatment would reduce mortality by 88·9% (84·0-89·3), averting 13·3 million (13·1-13·6) deaths (with once-lifetime screening), or by 92·3% (88·4-93·0), averting 14·6 million (14·1-14·6) deaths (with twice-lifetime screening). By 2120, vaccination alone would reduce mortality by 89·5% (86·6-89·9), averting 45·8 million (44·7-46·4) deaths. By 2120, additionally scaling up screening and cancer treatment would reduce mortality by 97·9% (95·0-98·0), averting 60·8 million (60·2-61·2) deaths (with once-lifetime screening), or by 98·6% (96·5-98·6), averting 62·6 million (62·1-62·8) deaths (with twice-lifetime screening). With the WHO triple-intervention strategy, over the next 10 years, about half (48% [45-55]) of deaths averted would be in sub-Saharan Africa and almost a third (32% [29-34]) would be in South Asia; over the next 100 years, almost 90% of deaths averted would be in these regions. For premature deaths (age 30-69 years), the WHO triple-intervention strategy would result in rate reductions of 33·9% (24·4-37·9) by 2030, 96·2% (94·3-96·8) by 2070, and 98·6% (96·9-98·8) by 2120.

INTERPRETATION

These findings emphasise the importance of acting immediately on three fronts to scale up vaccination, screening, and treatment for pre-invasive and invasive cervical cancer. In the next 10 years, a one-third reduction in the rate of premature mortality from cervical cancer in LMICs is possible, contributing to the realisation of the 2030 UN SDGs. Over the next century, successful implementation of the WHO elimination strategy would reduce cervical cancer mortality by almost 99% and save more than 62 million women's lives.

FUNDING

WHO, UNDP, UN Population Fund, UNICEF-WHO-World Bank Special Program of Research, Development and Research Training in Human Reproduction, Germany Federal Ministry of Health, National Health and Medical Research Council Australia, Centre for Research Excellence in Cervical Cancer Control, Canadian Institute of Health Research, Compute Canada, and Fonds de recherche du Québec-Santé.

The healthcare costs of treating human papillomavirus-related cancers in Norway

Background

Public health efforts to prevent human papillomavirus (HPV)-related cancers include HPV vaccination and cervical cancer screening. We quantified the annual healthcare cost of six HPV-related cancers in order to provide inputs in cost-effectiveness analyses and quantify the potential economic savings from prevention of HPV-related cancers in Norway.

Methods

Using individual patient-level data from three unlinked population-based registries, we estimated the mean healthcare costs 1) annually across all phases of disease, 2) during the first 3 years of care following diagnosis, and 3) for the last 12 months of life for patients diagnosed with an HPV-related cancer. We included episodes of care related to primary care physicians, specialist care (private specialists and hospital-based care and prescriptions), and prescription drugs redeemed at pharmacies outside hospitals between 2012 and 2014. We valued costs (2014 €1.00 = NOK 8.357) based on diagnosis-related groups (DRG), patient copayments, reimbursement fees and pharmacy retail prices.

Results

In 2014, the total healthcare cost of HPV-related cancers amounted to €39.8 million, of which specialist care accounted for more than 99% of the total cost. The annual maximum economic burden potentially averted due to HPV vaccination will be lower for vulvar, penile and vaginal cancer (i.e., €984,620, €762,964 and €374,857, respectively) than for cervical, anal and oropharyngeal cancers (i.e., €17.2 million, €6.7 million and €4.6 million, respectively). Over the first three years of treatment following cancer diagnosis, patients diagnosed with oropharyngeal cancer incurred the highest total cost per patient (i.e. €49,774), while penile cancer had the lowest total cost per patient (i.e. €18,350). In general, costs were highest the first year following diagnosis and then declined; however, costs increased rapidly again towards end of life for patients who did not survive.

Conclusion

HPV-related cancers constitute a considerable economic burden to the Norwegian healthcare system. As the proportion of HPV-vaccinated individuals increase and secondary prevention approaches advance, this study highlights the potential economic burden avoided by preventing these cancers.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5596-2) contains supplementary material, which is available to authorized users.

Scale-up of radiotherapy for cervical cancer in the era of human papillomavirus vaccination in low-income and middle-income countries: a model-based analysis of need and economic impact

BACKGROUND

Radiotherapy is standard of care for cervical cancer, but major global gaps in access exist, particularly in low-income and middle-income countries. We modelled the health and economic benefits of a 20-year radiotherapy scale-up to estimate the long-term demand for treatment in the context of human papillomavirus (HPV) vaccination.

METHODS

We applied the Global Task Force on Radiotherapy for Cancer Control investment framework to model the health and economic benefits of scaling up external-beam radiotherapy and brachytherapy for cervical cancer in upper-middle-income, lower-middle-income, and low-income countries between 2015 and 2035. We estimated the unique costs of external-beam radiotherapy and brachytherapy and included a specific valuation of women's caregiving contributions. Model outcomes life-years gained and the human capital and full income net present value of investment. We estimated the effects of stage at diagnosis, radiotherapy delivery system, and simultaneous HPV vaccination (75% coverage) up to a time horizon set at 2072.

FINDINGS

For the period from 2015 to 2035, we estimated that 9·4 million women in low-income and middle-income countries required treatment with external-beam radiotherapy, of which 7·0 million also required treatment with brachytherapy. Incremental scale-up of radiotherapy in these countries from 2015 to meet optimal radiotherapy demand by 2035 yielded 11·4 million life-years gained, $59·3 billion in human capital net present value (-$1·5 billion in low-income, $19·9 billion in lower-middle-income, and $40·9 billion in upper-middle-income countries), and $151·5 billion in full income net present value ($1·5 billion in low-income countries, $53·6 billion in lower-middle-income countries, and $96·4 billion in upper-middle-income countries). Benefits increased with advanced stage of cervical cancer and more efficient scale up of radiotherapy. Bivalent HPV vaccination of 12-year-old girls resulted in a 3·9% reduction in incident cases from 2015-2035. By 2072, when the first vaccinated cohort of girls reaches 70 years of age, vaccination yielded a 22·9% reduction in cervical cancer incidence, with 38·4 million requiring external-beam radiotherapy and 28·8 million requiring brachytherapy.

INTERPRETATION

Effective cervical cancer control requires a comprehensive strategy. Even with HPV vaccination, radiotherapy treatment scale-up remains essential and produces large health benefits and a strong return on investment to countries at different levels of development.

FUNDING

None.

Development and Calibration of a Mathematical Model of Anal Carcinogenesis for High-Risk HIV-Infected Men

OBJECTIVES

Men who have sex with men who are living with HIV are at highest risk for anal cancer. Our objective was to use empirical data to develop a comprehensive disease simulation model that reflects the most current understanding of anal carcinogenesis, which is uniquely positioned to evaluate future anal cancer screening strategies and provide insight on the unobservable course of the disease.

SETTING

North America.

METHODS

The individual-based simulation model was calibrated leveraging primary data from empirical studies, such as a longitudinal HIV-positive men who have sex with men cohort study [Human Immunodeficiency and Papilloma Virus Research Group (HIPVIRG); n = 247] and the North American AIDS Cohort Collaboration on Research and Design [(NA-ACCORD); n = 13,146]. We used the model to infer unobservable progression probabilities from high-grade precancer to invasive anal cancer by CD4 nadir and human papillomavirus (HPV) genotype.

RESULTS

The calibrated model had good correspondence to data on genotype- and age-specific HPV prevalence; genotype frequency in precancer and cancer; and age- and nadir CD4-specific cancer incidence. The model-projected progression probabilities differed substantially by HPV genotype and nadir CD4 status. For example, among individuals with CD4 nadir <200, the median monthly progression probability from a high-grade lesion to invasive cancer was 0.054% (ie, 6.28% 10-year probability) and 0.004% (ie, 0.48% 10-year probability) for men with an HPV-16 infection versus without a detectable HPV infection, respectively.

CONCLUSIONS

We synthesized existing evidence into a state-of-the-art anal cancer disease simulation model that will be used to quantify the tradeoffs of harms and benefits of alternative strategies, understand critical uncertainties, and inform national anal cancer prevention policy.

Screening for Cervical Cancer in Primary Care: A Decision Analysis for the US Preventive Services Task Force

IMPORTANCE

Evidence on the relative benefits and harms of primary high-risk human papillomavirus (hrHPV) testing is needed to inform guidelines.

OBJECTIVE

To inform the US Preventive Services Task Force by modeling the benefits and harms of various cervical cancer screening strategies.

DESIGN, SETTING, AND PARTICIPANTS

Microsimulation model of a hypothetical cohort of women initiating screening at age 21 years.

EXPOSURES

Screening with cytology, hrHPV testing, and cytology and hrHPV cotesting, varying age to switch from cytology to hrHPV testing or cotesting (25, 27, 30 years), rescreening interval (3, 5 years), and triage options for hrHPV-positive results (16/18 genotype, cytology testing). Current guidelines-based screening strategies comprised cytology alone every 3 years starting at age 21 years, with or without a switch to cytology and hrHPV cotesting every 5 years from ages 30 to 65 years. Complete adherence for all 19 strategies was assumed.

MAIN OUTCOMES AND MEASURES

Lifetime number of tests, colposcopies, disease detection, false-positive results, cancer cases and deaths, life-years, and efficiency ratios expressing the trade-off of harms (ie, colposcopies, tests) vs benefits (life-years gained, cancer cases averted). Efficient strategies were those that yielded more benefit and less harm than another strategy or a lower harm to benefit ratio than a strategy with less harms.

RESULTS

Compared with no screening, all modeled cervical cancer screening strategies were estimated to result in substantial reductions in cancer cases and deaths and gains in life-years. The effectiveness of screening across the different strategies was estimated to be similar, with primary hrHPV-based and alternative cotesting strategies having slightly higher effectiveness and greater harms than current guidelines-based cytology testing. For example, cervical cancer deaths associated with the guidelines-based strategies ranged from 0.30 to 0.76 deaths per 1000 women, whereas new strategies involving primary hrHPV testing or cotesting were associated with fewer cervical cancer deaths, ranging from 0.23 to 0.29 deaths per 1000 women. In all analyses, primary hrHPV testing strategies occurring at 5-year intervals were efficient. For example, 5-year primary hrHPV testing (cytology triage) based on switching from cytology to hrHPV screening at ages 30 years, 27 years, and 25 years had ratios per life-year gained of 73, 143, and 195 colposcopies, respectively. In contrast, strategies involving 3-year hrHPV testing had much higher ratios, ranging from 2188 to 3822 colposcopies per life-year gained. In most analyses, strategies involving cotesting were not efficient.

CONCLUSIONS AND RELEVANCE

In this microsimulation modeling study, it was estimated that primary hrHPV screening may represent a reasonable balance of harms and benefits when performed every 5 years. Switching from cytology to hrHPV testing at age 30 years yielded the most efficient harm to benefit ratio when using colposcopy as a proxy for harms.

Inefficiencies of over-screening and under-screening for cervical cancer prevention in the U.S

There is limited information on the cost-inefficiencies of non-adherence to recommended cervical cancer screening or the potential value for improving non-adherence. We estimated the incremental value of adhering to recommended screening every three years with cytology, using a disease simulation model that integrated real-world screening practice data from New Mexico. The amount that can be spent to improve adherence was estimated by calculating the incremental net monetary benefit (INMB) under scenarios of Current Practice (assuming a population of mixed adherence) and Uniformly Non-Adherent populations with imperfect or perfect adherence to follow-up of screen-positive women. Getting unscreened women screened every three years by cytology was a better value than increasing screening in the under-screened or reducing screening in the over-screened. For example, INMBs were $3998 for screening previously unscreened women versus $136 for eliminating annual screening at a willingness-to-pay threshold of $100,000 per quality-adjusted life-year gained. Strategies to reach unscreened women are potentially high-value investments.

Health and economic benefits of single-dose HPV vaccination in a Gavi-eligible country

BACKGROUND

Although guidelines for prophylactic human papillomavirus (HPV) vaccination recommend two doses for girls ages 9-14 years, several studies have demonstrated similar protection with one dose. Our objective was to evaluate the long-term health and economic impacts of routine one-dose HPV vaccination compared to (1) no vaccination and (2) two-dose HPV vaccination in a low-income country.

METHODS

We used a three-tiered hybrid modeling approach that captured HPV transmission, cervical carcinogenesis, and population demographics to project long-term health and economic outcomes associated with one-dose HPV vaccination (assuming 80% efficacy against HPV-16/18 infections under three waning scenarios) and two-dose HPV vaccination (assuming 100% efficacy over the lifetime) in Uganda. Costs included the vaccine program (dosage and delivery) costs over a 10-year period and cervical cancer costs over the lifetimes of the current population of Ugandan women. Health outcomes included number of cervical cancer cases and disability-adjusted life years (DALYs). Incremental cost-effectiveness ratios (i.e., cost per DALY averted) were calculated and compared against the Ugandan per-capita gross domestic product.

RESULTS

Routine one-dose HPV vaccination of 9-year-old girls required substantial upfront investment but was cost-saving compared to no vaccination when accounting for the cost-offsets from future cancers averted. Forty years after initiating routine vaccination and depending on assumptions of vaccine waning, one-dose HPV vaccination with equivalent coverage (70%) averted 15-16% of cervical cancer cases versus 21% with two-dose vaccination but required only half the upfront economic investment. Vaccination with two doses had an attractive cost-effectiveness profile except if one-dose vaccination enabled higher coverage (90% vs. 70%) and did not wane.

CONCLUSIONS

One-dose HPV vaccination resulted in cost-savings compared to no vaccination and could be cost-effective compared to two-dose vaccination if protection is longstanding and higher coverage can be achieved.

An overview of cervical cancer epidemiology and prevention in Scandinavia

New technologies such as human papillomavirus (HPV) testing and vaccination necessitate comprehensive policy analyses to optimize cervical cancer prevention. To inform future Scandinavian-specific policy analyses, we aimed to provide an overview of cervical cancer epidemiology and existing prevention efforts in Denmark, Norway and Sweden. We compiled and summarized data on current prevention strategies, population demography and epidemiology (for example, age-specific HPV prevalence and cervical cancer incidence over time) for each Scandinavian country by reviewing published literature and official guidelines, performing registry-based analyses using primary data and having discussions with experts in each country. In Scandinavia, opportunistic screening occurred as early as the 1950s and by 1996, all countries had implemented nationwide organized cytology-based screening. Prior to implementation of widespread screening and during 1960-66, cervical cancer incidence was considerably higher in Denmark than in Norway and Sweden. Decades of cytology-based screening later (i.e. 2010-2014), cervical cancer incidence has been considerably reduced and has converged across the countries since the 1960s, although it still remains lowest in Sweden. Generally, Scandinavian countries face similar cervical cancer burdens and utilize similar prevention approaches; however, important differences remain. Future policy analyses will need to evaluate whether these differences warrant differential prevention policies or whether efforts can be streamlined across Scandinavia.

Age of Acquiring Causal Human Papillomavirus (HPV) Infections: Leveraging Simulation Models to Explore the Natural History of HPV-induced Cervical Cancer

Background

Although new human papillomavirus (HPV) infections can occur at all ages, the age at which women acquire their "causal" HPV infection that develops into cervical cancer is poorly understood and practically unobservable. We aimed to estimate the age distribution at which individuals acquired their causal HPV infection in the absence of HPV vaccination or screening to help guide the optimal use of both.

Methods

Using an empirically calibrated mathematical model that simulates the natural history of cervical cancer, we estimated the cumulative number of causal HPV infections by age, stratified by HPV genotype (HPV16 vs. other HPV genotypes), and the direct age-specific reduction in cancer incidence for alternative vaccination initiation scenarios (i.e., age 9-45 years).

Results

Our model projected that among all cervical cancers, 50% and 75% of women acquired their causal HPV infection by ages 20.6 (range: 20.1-21.1) and 30.6 (range: 29.6-31.6) years, respectively. HPV16 infections were acquired at an earlier age. Assuming 95% efficacy against HPV16 and HPV18 infections, the direct reduction in lifetime risk of cervical cancer varied from 55% (53-56%) among women vaccinated at age 9 years to 6% (range: 6-7%) among women vaccinated at age 45 years. Similar patterns were observed for the second-generation vaccine.

Conclusions

Although new HPV infections and precancers can occur throughout a woman's lifetime, only a small proportion are acquired in mid-adult women and are vaccine-preventable. Our simulations highlight the potential limitations of using surrogate endpoints for vaccine efficacy studies of mid-adult women to guide policy decisions for implementation.

Effect of Time to Diagnostic Testing for Breast, Cervical, and Colorectal Cancer Screening Abnormalities on Screening Efficacy: A Modeling Study

Background: Patients who receive an abnormal cancer screening result require follow-up for diagnostic testing, but the time to follow-up varies across patients and practices.Methods: We used a simulation study to estimate the change in lifetime screening benefits when time to follow-up for breast, cervical, and colorectal cancers was increased. Estimates were based on four independently developed microsimulation models that each simulated the life course of adults eligible for breast (women ages 50-74 years), cervical (women ages 21-65 years), or colorectal (adults ages 50-75 years) cancer screening. We assumed screening based on biennial mammography for breast cancer, triennial Papanicolaou testing for cervical cancer, and annual fecal immunochemical testing for colorectal cancer. For each cancer type, we simulated diagnostic testing immediately and at 3, 6, and 12 months after an abnormal screening exam.Results: We found declines in screening benefit with longer times to diagnostic testing, particularly for breast cancer screening. Compared to immediate diagnostic testing, testing at 3 months resulted in reduced screening benefit, with fewer undiscounted life years gained per 1,000 screened (breast: 17.3%, cervical: 0.8%, colorectal: 2.0% and 2.7%, from two colorectal cancer models), fewer cancers prevented (cervical: 1.4% fewer, colorectal: 0.5% and 1.7% fewer, respectively), and, for breast and colorectal cancer, a less favorable stage distribution.Conclusions: Longer times to diagnostic testing after an abnormal screening test can decrease screening effectiveness, but the impact varies substantially by cancer type.Impact: Understanding the impact of time to diagnostic testing on screening effectiveness can help inform quality improvement efforts. Cancer Epidemiol Biomarkers Prev; 27(2); 158-64. ©2017 AACR.

Adapting cervical cancer screening for women vaccinated against human papillomavirus infections: The value of stratifying guidelines

BACKGROUND

Several countries have implemented vaccination against human papillomavirus (HPV) for adolescent girls and must decide whether and how to adapt cervical cancer (CC) screening for these low-risk women. We aimed to identify the optimal screening strategies for women vaccinated against HPV infections and quantify the amount that could be spent to identify vaccination status among women and stratify CC screening guidelines accordingly.

METHODS

We used a mathematical model reflecting HPV-induced CC in Norway to project the long-term health benefits, resources and costs associated with 74 candidate-screening strategies that varied by screening test, start age and frequency. Strategies were considered separately for women vaccinated with the bivalent/quadrivalent (2/4vHPV) and nonavalent (9vHPV) vaccines. We used a cost-effectiveness framework (i.e. incremental cost-effectiveness ratios and net monetary benefit) and a commonly-cited Norwegian willingness-to-pay threshold of €75,000 per quality-adjusted life-year gained.

RESULTS

The most cost-effective screening strategy for 9vHPV- and 2/4vHPV-vaccinated women involved HPV testing once and twice per lifetime, respectively. The value of stratifying guidelines by vaccination status was €599 (2/4vHPV) and €725 (9vHPV) per vaccinated woman. Consequently, for the first birth cohort of ∼22,000 women who were vaccinated in adolescence in Norway, between €10.5-13.2 million over their lifetime could be spent on identifying individual vaccination status and stratify screening while remaining cost-effective.

CONCLUSION

Less intensive strategies are required for CC screening to remain cost-effective in HPV-vaccinated women. Moreover, screening can remain cost-effective even if large investments are made to identify individual vaccination status and stratify screening guidelines accordingly.

Choosing wisely: a model-based analysis evaluating the trade-offs in cancer benefit and diagnostic referrals among alternative HPV testing strategies in Norway

Background:

Forthcoming cervical cancer screening strategies involving human papillomavirus (HPV) testing for women not vaccinated against HPV infections may increase colposcopy referral rates. We quantified health and resource trade-offs associated with alternative HPV-based algorithms to inform decision-makers when choosing between candidate algorithms.

Methods:

We used a mathematical simulation model of HPV-induced cervical carcinogenesis in Norway. We compared the current cytology-based strategy to alternative strategies that varied by the switching age to primary HPV testing (ages 25–34 years), the routine screening frequency (every 3–10 years), and management of HPV-positive, cytology-negative women. Model outcomes included reductions in lifetime cervical cancer risk, relative colposcopy rates, and colposcopy rates per cervical cancer prevented.

Results:

The age of switching to primary HPV testing and the screening frequency had the largest impacts on cancer risk reductions, which ranged from 90.9% to 96.3% compared to no screening. In contrast, increasing the follow-up intensity of HPV-positive, cytology-negative women provided only minor improvements in cancer benefits, but generally required considerably higher rates of colposcopy referrals compared to current levels, resulting in less efficient cervical cancer prevention.

Conclusions:

We found that in order to maximise cancer benefits HPV-based screening among unvaccinated women should not be delayed: rather, policy makers should utilise the triage mechanism to control colposcopy referrals.

Population-level impact, herd immunity, and elimination after human papillomavirus vaccination: a systematic review and meta-analysis of predictions from transmission-dynamic models

BACKGROUND

Modelling studies have been widely used to inform human papillomavirus (HPV) vaccination policy decisions; however, many models exist and it is not known whether they produce consistent predictions of population-level effectiveness and herd effects. We did a systematic review and meta-analysis of model predictions of the long-term population-level effectiveness of vaccination against HPV 16, 18, 6, and 11 infection in women and men, to examine the variability in predicted herd effects, incremental benefit of vaccinating boys, and potential for HPV-vaccine-type elimination.

METHODS

We searched MEDLINE and Embase for transmission-dynamic modelling studies published between Jan 1, 2009, and April 28, 2015, that predicted the population-level impact of vaccination on HPV 6, 11, 16, and 18 infections in high-income countries. We contacted authors to determine whether they were willing to produce new predictions for standardised scenarios. Strategies investigated were girls-only vaccination and girls and boys vaccination at age 12 years. Base-case vaccine characteristics were 100% efficacy and lifetime protection. We did sensitivity analyses by varying vaccination coverage, vaccine efficacy, and duration of protection. For all scenarios we pooled model predictions of relative reductions in HPV prevalence (RRprev) over time after vaccination and summarised results using the median and 10th and 90th percentiles (80% uncertainty intervals [UI]).

FINDINGS

16 of 19 eligible models from ten high-income countries provided predictions. Under base-case assumptions, 40% vaccination coverage and girls-only vaccination, the RRprev of HPV 16 among women and men was 0·53 (80% UI 0·46-0·68) and 0·36 (0·28-0·61), respectively, after 70 years. With 80% girls-only vaccination coverage, the RRprev of HPV 16 among women and men was 0·93 (0·90-1·00) and 0·83 (0·75-1·00), respectively. Vaccinating boys in addition to girls increased the RRprev of HPV 16 among women and men by 0·18 (0·13-0·32) and 0·35 (0·27-0·39) for 40% coverage, and 0·07 (0·00-0·10) and 0·16 (0·01-0·25) for 80% coverage, respectively. The RRprev were greater for HPV 6, 11, and 18 than for HPV 16 for all scenarios investigated. Finally at 80% coverage, most models predicted that girls and boys vaccination would eliminate HPV 6, 11, 16, and 18, with a median RRprev of 1·00 for women and men for all four HPV types. Variability in pooled findings was low, but increased with lower vaccination coverage and shorter vaccine protection (from lifetime to 20 years).

INTERPRETATION

Although HPV models differ in structure, data used for calibration, and settings, our population-level predictions were generally concordant and suggest that strong herd effects are expected from vaccinating girls only, even with coverage as low as 20%. Elimination of HPV 16, 18, 6, and 11 is possible if 80% coverage in girls and boys is reached and if high vaccine efficacy is maintained over time.

FUNDING

Canadian Institutes of Health Research.

Optimal Cervical Cancer Screening in Women Vaccinated Against Human Papillomavirus

Background

Current US cervical cancer screening guidelines do not differentiate recommendations based on a woman's human papillomavirus (HPV) vaccination status. Changes to cervical cancer screening policies in HPV-vaccinated women should be evaluated.

Methods

We utilized an individual-based mathematical model of HPV and cervical cancer in US women to project the health benefits, costs, and harms associated with screening strategies in women vaccinated with the bivalent, quadrivalent, or nonavalent vaccine. Strategies varied by the primary screening test, including cytology, HPV, and combined cytology and HPV "cotesting"; age of screening initiation and/or switching to a new test; and interval between routine screens. Cost-effectiveness analysis was conducted from the societal perspective to identify screening strategies that would be considered good value for money according to thresholds of $50 000 to $200 000 per quality-adjusted life-year (QALY) gained.

Results

Among women fully vaccinated with the bivalent or quadrivalent vaccine, optimal screening strategies involved either cytology or HPV testing alone every five years starting at age 25 or 30 years, with cost-effectiveness ratios ranging from $34 680 to $138 560 per QALY gained. Screening earlier or more frequently was either not cost-effective or associated with exceedingly high cost-effectiveness ratios. In women vaccinated with the nonavalent vaccine, only primary HPV testing was efficient, involving decreased frequency (ie, every 10 years) starting at either age 35 years ($40 210 per QALY) or age 30 years ($127 010 per QALY); with lower nonavalent vaccine efficacy, 10-year HPV testing starting at earlier ages of 25 or 30 years was optimal. Importantly, current US guidelines for screening were inefficient in HPV-vaccinated women.

Conclusions

This model-based analysis suggests screening can be modified to start at later ages, occur at decreased frequency, and involve primary HPV testing in HPV-vaccinated women, providing more health benefit at lower harms and costs than current screening guidelines.

The Cost-Effectiveness of Cervical Self-Sampling to Improve Routine Cervical Cancer Screening: The Importance of Respondent Screening History and Compliance

BACKGROUND

Human papillomavirus (HPV) testing allows women to self-collect cervico-vaginal cells at home (i.e., self-sampling). Using primary data from a randomized pilot study, we evaluated the long-term consequences and cost-effectiveness of using self-sampling to improve participation to routine cervical cancer screening in Norway.

METHODS

We compared a strategy reflecting screening participation (using reminder letters) to strategies that involved mailing self-sampling device kits to women noncompliant to screening within a 5- or 10-year period under two scenarios: (A) self-sampling respondents had moderate under-screening histories, or (B) respondents to self-sampling had moderate and severe under-screening histories. Model outcomes included quality-adjusted life-years (QALY) and lifetime costs. The "most cost-effective" strategy was identified as the strategy just below $100,000 per QALY gained.

RESULTS

Mailing self-sampling device kits to all women noncompliant to screening within a 5- or 10-year period can be more effective and less costly than the current reminder letter policy; however, the optimal self-sampling strategy was dependent on the profile of self-sampling respondents. For example, "10-yearly self-sampling" is preferred ($95,500 per QALY gained) if "5-yearly self-sampling" could only attract moderate under-screeners; however, "5-yearly self-sampling" is preferred if this strategy could additionally attract severe under-screeners.

CONCLUSIONS

Targeted self-sampling of noncompliers likely represents good value-for-money; however, the preferred strategy is contingent on the screening histories and compliance of respondents.

IMPACT

The magnitude of the health benefit and optimal self-sampling strategy is dependent on the profile and behavior of respondents. Health authorities should understand these factors prior to selecting and implementing a self-sampling policy. Cancer Epidemiol Biomarkers Prev; 26(1); 95-103. ©2016 AACR.

Cost-effective management of women with minor cervical lesions: Revisiting the application of HPV DNA testing

BACKGROUND

Lack of consensus in management guidelines for women with minor cervical lesions, coupled with novel screening approaches, such as human papillomavirus (HPV) genotyping, necessitate revisiting prevention policies. We evaluated the cost-effectiveness and resource trade-offs of alternative triage strategies to inform cervical cancer prevention in Norway.

METHODS

We used a decision-analytic model to compare the lifetime health and economic consequences associated with ten novel candidate approaches to triage women with minor cervical lesions. Candidate strategies varied by: 1) the triage test(s): HPV testing in combination with cytology, HPV testing alone with or without genotyping for HPV-16 and -18, and immediate colposcopy, and 2) the length of time between index and triage testing (i.e., 6, 12 or 18months). Model outcomes included quality-adjusted life-years (QALYs), lifetime societal costs, and resource use (e.g., colposcopy referrals).

RESULTS

The current Norwegian guidelines were less effective and more costly than candidate strategies. Given a commonly-cited willingness-to-pay threshold in Norway of $100,000 per QALY gained, the preferred strategy involved HPV genotyping with immediate colposcopy referral for HPV-16 or -18 positive and repeat HPV testing at 12months for non-HPV-16 or -18 positive ($78,010 per QALY gained). Differences in health benefits among candidate strategies were small, while resource use varied substantially. More effective strategies required a moderate increase in colposcopy referrals (e.g., a 9% increase for the preferred strategy) compared with current levels.

CONCLUSION

New applications of HPV testing may improve management of women with minor cervical lesions, yet are accompanied by a trade-off of increased follow-up procedures.