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

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.

Projected Time for the Elimination of Cervical Cancer Under Various Intervention Scenarios: Age-Period-Cohort Macrosimulation Study

BACKGROUND

The World Health Organization aims for the global elimination of cervical cancer, necessitating modeling studies to forecast long-term outcomes.

OBJECTIVE

This paper introduces a macrosimulation framework using age-period-cohort modeling and population attributable fractions to predict the timeline for eliminating cervical cancer in Taiwan.

METHODS

Data for cervical cancer cases from 1997 to 2016 were obtained from the Taiwan Cancer Registry. Future incidence rates under the current approach and various intervention strategies, such as scaled-up screening (cytology based or human papillomavirus [HPV] based) and HPV vaccination, were projected.

RESULTS

Our projections indicate that Taiwan could eliminate cervical cancer by 2050 with either 70% compliance in cytology-based or HPV-based screening or 90% HPV vaccination coverage. The years projected for elimination are 2047 and 2035 for cytology-based and HPV-based screening, respectively; 2050 for vaccination alone; and 2038 and 2033 for combined screening and vaccination approaches.

CONCLUSIONS

The age-period-cohort macrosimulation framework offers a valuable policy analysis tool for cervical cancer control. Our findings can inform strategies in other high-incidence countries, serving as a benchmark for global efforts to eliminate the disease.

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.

Strategies to eliminate cervical cancer in China

Cervical cancer is a widely distributed disease that is preventable and controllable through early intervention. The World Health Organization has identified three key measures, coverage populations and coverage targets to eliminate cervical cancer. The WHO and several countries have conducted model predictions to determine the optimal strategy and timing of cervical cancer elimination. However, specific implementation strategies need to be developed in the context of local conditions. China has a relatively high disease burden of cervical cancer but a low human papillomavirus vaccination rate and cervical cancer screening population coverage. The purpose of this paper is to review interventions and prediction studies for the elimination of cervical cancer and to analyze the problems, challenges and strategies for the elimination of cervical cancer in China.

Unpacking the Lay Epidemiology of Cervical Cancer: A Focus Group Study on the Perceptions of Cervical Cancer and Its Prevention among Women Late for Screening in Norway

Nonattendance for cervical cancer screening is often understood in terms of a lack of 'appropriate' or 'correct' knowledge about the risks and prevention of the disease. Few studies have explored how lay persons-the users themselves-interpret and contextualise scientific knowledge about cervical cancer. In this study, we address the following research question: How is the epidemiology of cervical cancer and its prevention discussed among women who are late for cervical cancer screening in Norway? We completed nine focus group interviews (FGIs) with 41 women who had postponed cervical screening. The analyses were both inductive and explorative, aiming to unpack the complexity of lay understandings of cervical cancer. Interactive associations expressed in the FGIs reflected multiple understandings of aetiology and risk factors, screening, and interpretations of responsibility for acquiring cervical cancer. The term 'candidacy' was employed to provide an enhanced understanding of lay reasoning about the explanations and predictions of cervical cancer, as reflected in the FGIs. Both interpretations of biomedical concepts and cultural values were used to negotiate acceptable and nuanced interpretations of candidacy for cervical cancer. Uncertainties about risk factors for acquiring cervical cancer was an important aspect of such negotiations. The study's findings provide an in-depth understanding of the contexts in which screening may be rendered less relevant or significant for maintaining health. Lay epidemiology should not be considered inappropriate knowledge but rather as a productive component when understanding health behaviours, such as screening attendance.

Accounting for Adverse Events Following Immunization in Economic Evaluation: Systematic Review of Economic Evaluations of Pediatric Vaccines Against Pneumococcus, Rotavirus, Human Papillomavirus, Meningococcus and Measles-Mumps-Rubella-Varicella

OBJECTIVES

Economic evaluations of vaccines should accurately represent all relevant economic and health consequences of vaccination, including losses due to adverse events following immunization (AEFI). We investigated to what extent economic evaluations of pediatric vaccines account for AEFI, which methods are used to do so and whether inclusion of AEFI is associated with study characteristics and the vaccine's safety profile.

METHODS

A systematic literature search (MEDLINE, EMBASE, Cochrane Systematic Reviews and Trials, Database of the Centre for Reviews and Dissemination of the University of York, EconPapers, Paediatric Economic Database Evaluation, Tufts New England Cost-Effectiveness Analysis Registry, Tufts New England Global Health CEA, International Network of Agencies for Health Technology Assessment Database) was performed for economic evaluations published between 2014 and 29 April 2021 (date of search) pertaining to the five groups of pediatric vaccines licensed in Europe and the United States since 1998: the human papillomavirus (HPV) vaccines, the meningococcal vaccines (MCV), the measles-mumps-rubella-varicella (MMRV) combination vaccines, the pneumococcal conjugate vaccines (PCV) and the rotavirus vaccines (RV). Rates of accounting for AEFI were calculated, stratified by study characteristics (e.g., region, publication year, journal impact factor, level of industry involvement) and triangulated with the vaccine's safety profile (Advisory Committee on Immunization Practices [ACIP] recommendations and information on safety-related product label changes). The studies accounting for AEFI were analyzed in terms of the methods used to account for both cost and effect implications of AEFI.

RESULTS

We identified 112 economic evaluations, of which 28 (25%) accounted for AEFI. This proportion was significantly higher for MMRV (80%, four out of five evaluations), MCV (61%, 11 out of 18 evaluations) and RV (60%, nine out of 15 evaluations) compared to HPV (6%, three out of 53 evaluations) and PCV (5%, one out of 21 evaluations). No other study characteristics were associated with a study's likelihood of accounting for AEFI. Vaccines for which AEFI were more frequently accounted for also had a higher frequency of label changes and a higher level of attention to AEFI in ACIP recommendations. Nine studies accounted for both the cost and health implications of AEFI, 18 studies considered only costs and one only health outcomes. While the cost impact was usually estimated based on routine billing data, the adverse health impact of AEFI was usually estimated based on assumptions.

DISCUSSION

Although (mild) AEFI were demonstrated for all five studied vaccines, only a quarter of reviewed studies accounted for these, mostly in an incomplete and inaccurate manner. We provide guidance on which methods to use to better quantify the impact of AEFI on both costs and health outcomes. Policymakers should be aware that the impact of AEFI on cost-effectiveness is likely to be underestimated in the majority of economic evaluations.

An overview of cervical cancer epidemiology and prevention in the Baltic States

AIMS

To inform future Baltic States-specific policy analyses, we aimed to provide an overview of cervical cancer epidemiology and existing prevention efforts in Estonia, Latvia and Lithuania.

METHODS

A structured desk review: we compiled and summarized data on current prevention strategies, population demography and epidemiology (high risk human papillomavirus (HPV) prevalence and cervical cancer incidence and mortality over time) for each Baltic State by reviewing published literature and official guidelines, performing registry-based analyses using secondary data and having discussions with experts in each country.

RESULTS

We observed important similarities in the three Baltic States: high burden of the disease (high incidence and mortality of cervical cancer, changes in TNM (Classification of Malignant Tumors) stage distribution towards later stage at diagnosis), high burden of high-risk HPV in general population and suboptimal implementation of the preventive strategies as low screening and HPV vaccination coverage.

CONCLUSIONS

Cervical cancer remains a substantial health problem in the region and the efforts in addressing barriers by implementing a four-step plan for elimination cervical cancer in Europe should be made. This goal is achievable through evidence-based steps in four key areas: vaccination, screening, treatment, and public awareness.

Adjuvant Human Papillomavirus Vaccination After Excisional Procedure for Cervical Intraepithelial Neoplasia: A Cost-Effectiveness Analysis

OBJECTIVE

To examine the cost effectiveness of human papillomavirus (HPV) vaccination after excisional procedure compared with no vaccination.

METHODS

We constructed a decision-analytic model (TreeAge Pro 2021) to compare outcomes between patients who underwent an excisional procedure followed by nonavalent HPV vaccination to those who underwent an excisional procedure without vaccination. Our theoretical cohort contained 250,000 patients, the approximate number undergoing excisional procedures annually in the United States. Our outcomes were costs, quality-adjusted life-years (QALYs), recurrence events, number of surveillance Pap tests with co-testing, number of colposcopies, and second excisional procedures. Probabilities of recurrence were based on a recently published meta-analysis. All values were derived from the literature, and QALYs were discounted at a rate of 3%. Outcomes were applied for 4 years after the initial excisional procedure. Our cost-effectiveness threshold was $100,000 per QALY. Sensitivity analyses were performed to evaluate the robustness of the model.

RESULTS

In our theoretical cohort of patients who underwent an excisional procedure, the HPV vaccination strategy was associated with 17,281 fewer recurrences of cervical intraepithelial neoplasia (CIN) (8,360 fewer cases of CIN 1 and 8,921 fewer cases of CIN 2 or 3), 26,203 fewer Pap tests (1,025,368 vs 1,051,570), 17,281 fewer colposcopies (20,588 vs 37,869), and 8,921 fewer second excisional procedures (4,779 vs 13,701). The vaccination strategy was associated with a higher cost of $135 million. Vaccination was a cost-effective strategy, with an incremental cost-effectiveness ratio of $29,181 per QALY, compared with no vaccination. In our sensitivity analyses, the HPV vaccination strategy remained cost effective until the cost of the three-dose HPV vaccine series reached $1,899 or the baseline (nonvaccinated) probability of recurrence was less than 4.8%.

CONCLUSION

In our model, HPV vaccination for patients with a prior excisional procedure led to improved outcomes and was cost effective. Our study suggests that clinicians should consider offering the three-dose HPV vaccine series to patients who have undergone an excisional procedure to decrease the risk of CIN recurrence and its sequelae.

Public health impact and cost-effectiveness of switching from bivalent to nonavalent vaccine for human papillomavirus in Norway: incorporating the full health impact of all HPV-related diseases

AIM

The objective of this study was to estimate and compare the cost-effectiveness of switching from a bivalent to a nonavalent human papillomavirus (HPV) vaccination program in Norway, incorporating all nonavalent vaccine-preventable HPV-related diseases and in the context of the latest cervical cancer screening program.

METHODS

A well-established dynamic transmission model of the natural history of HPV infection and disease was adapted to the Norwegian population. We determined the number of cases of HPV-related diseases and subsequent number of deaths, and the economic burden of HPV-related disease under the current standard of care conditions of bivalent and nonavalent vaccinations of girls and boys aged 12 years.

RESULTS

Compared to bivalent vaccination, nonavalent vaccination averted an additional 4,357 cases of HPV-related cancers, 421,925 cases of genital warts, and 543 cases of recurrent respiratory papillomatosis (RRP) over a 100-year time horizon. Nonavalent vaccination also averted an additional 1,044 deaths over the 100-year time horizon when compared with bivalent vaccination. Total costs were higher for the nonavalent strategy (10.5 billion NOK [€1.03 billion] vs. 9.3-9.4 billion NOK [€915-925 million] for bivalent vaccination). A switch to nonavalent vaccination had a higher vaccination cost (4.4 billion NOK [€433 million] vs. 2.7 billion NOK [€266 million] for bivalent vaccination) but resulted in a savings of 627-694 million NOK [€62-68 million] in treatment costs. A switch to nonavalent vaccination demonstrated an incremental cost-effectiveness ratio of 102,500 NOK (€10,086) per QALY versus bivalent vaccination.

CONCLUSIONS

Using a model that incorporated the full range of HPV-related diseases, and the latest cervical cancer screening practices, we found that switching from bivalent to nonavalent vaccination would be considered cost-effective in Norway.

Rapid elimination of cervical cancer while maintaining the harms and benefits ratio of cervical cancer screening: a modelling study

BACKGROUND

Human papillomavirus (HPV) vaccination and intensifying screening expedite cervical cancer (CC) elimination, yet also deteriorate the balance between harms and benefits of screening. We aimed to find screening strategies that eliminate CC rapidly but maintain an acceptable harms-benefits ratio of screening.

METHODS

Two microsimulation models (STDSIM and MISCAN) were applied to simulate HPV transmission and CC screening for the Dutch female population between 2022 and 2100. We estimated the CC elimination year and harms-benefits ratios of screening for 228 unique scenarios varying in vaccination (coverage and vaccine type) and screening (coverage and number of lifetime invitations in vaccinated cohorts). The acceptable harms-benefits ratio was defined as the number of women needed to refer (NNR) to prevent one CC death under the current programme for unvaccinated cohorts (82.17).

RESULTS

Under current vaccination conditions (bivalent vaccine, 55% coverage in girls, 27.5% coverage in boys), maintaining current screening conditions is projected to eliminate CC by 2042, but increases the present NNR with 41%. Reducing the number of lifetime screens from presently five to three and increasing screening coverage (61% to 70%) would prevent an increase in harms and only delay elimination by 1 year. Scaling vaccination coverage to 90% in boys and girls with the nonavalent vaccine is estimated to eliminate CC by 2040 under current screening conditions, but exceeds the acceptable NNR with 23%. Here, changing from five to two lifetime screens would keep the NNR acceptable without delaying CC elimination.

CONCLUSIONS

De-intensifying CC screening in vaccinated cohorts leads to little or no delay in CC elimination while it substantially reduces the harms of screening. Therefore, de-intensifying CC screening in vaccinated cohorts should be considered to ensure acceptable harms-benefits ratios on the road to CC elimination.

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.

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.

Eliminating Cervical Cancer: Progress and Challenges for High-income Countries

In 2020, the World Health Organization launched a major initiative to eliminate cervical cancer globally. The initiative is built around the three key pillars of human papillomavirus (HPV) vaccination, cervical screening and treatment, with associated intervention targets for the year 2030. The '90-70-90' targets specify that 90% of adolescent girls receive prophylactic HPV vaccination, 70% of adult women receive a minimum twice-in-a-lifetime cervical HPV test and 90% receive appropriate treatment for preinvasive or invasive disease. Modelling has shown that if these targets are met, the elimination of cervical cancer, defined as fewer than four cases per 100 000 women per annum, will be achieved within a century. Many high-income countries are well positioned to eliminate cervical cancer within the coming decades, but few have achieved '90-70-90' and many challenges must still be addressed to deliver these critical interventions effectively. This review considers the current status of cervical cancer control in relation to each of the three elimination pillars in high-income countries and discusses some of the developments that will assist countries in reaching these ambitious targets by 2030.