Cost-effectiveness analysis for Pap smear screening and human papillomavirus DNA testing and vaccination

Impact of the COVID-19 pandemic on population-based cancer screening, a nationwide retrospective study in Taiwan

BACKGROUND

The Coronavirus disease 2019 (COVID-19) pandemic has placed a great burden on Taiwan's health care system. It has also had a great impact on other public health issues, including cancer screening. Delayed cancer screening was also noticed in the U.S. during the pandemic, which may have led to both delayed diagnosis and poor prognosis. In Taiwan, population-based cancer screening for breast cancer, oral cancer, colon cancer and cervical cancer has been executed and ongoing for years.

METHOD

In this study we have analyzed the change in screening numbers for cancer during the period of the 2019 to 2021 COVID-19 outbreak in Taiwan.

RESULTS

Through our results we found that total cancer screening numbers decreased from 307,547 to 103,289 (a 66% decrease) from the years 2020 to 2021. Specifically, a 63%, 79%, 65% and 71% decrease in screening cases was seen for colon cancer, oral cancer, cervical cancer and breast cancer, respectively, during that period. A similar condition was noticed when comparing 2019 to 2021 when the disclosed total cancer screening numbers decreased by 70% (2019-2021); 65%, 83%, 70% and 76% in colon cancer, oral cancer, cervical cancer and breast cancer, respectively. Among these various cancer screenings, oral cancer screening showed the greatest reduction rate (a drop of 83% compared to 2019 and 79% compared to 2020). We also compared the reduction rates taken from different regions in Taiwan. It was in Taipei, where most COVID-19 cases were noted, that the greatest reduction rate of cancer screening numbers occurred (a drop of76% compared to 2019 and 74% compared to 2020). A proportional decrease of screening cases was also noticed in all areas when confirmed COVID-19 cases rose.

CONCLUSIONS

Screening for cancers dropped significantly due to the pandemic and its effect on long-term health needs to be evaluated. Additionally, efforts should be taken to address these cancer screening number deficits which have taken place during the COVID-19 pandemic.

The Effectiveness of Population Mass Screening to Oral Cancer: A Simulation Study

Background: Mass screening of high-risk populations for oral cancer has proven to be effective in reducing oral cancer mortality. However, the magnitude of the effectiveness of the various screening scenarios has rarely been addressed. Methods: We developed a simulation algorithm for a prospective cohort under various oral cancer screening scenarios. A hypothetical cohort of 8 million participants aged ≥30 years with cigaret smoking and/or betel quid chewing habits was constructed based on parameters extracted from studies on oral cancer screening. The results of a population-based screening program in Taiwan and a randomized controlled trial in India were used to validate the fitness; then, the effectiveness of the model was determined by changing the screening parameters. Results: There was a reduction in the risk of advanced oral cancer by 40% (relative risk [RR] = 0.60, 95% confidence interval [CI]:0.59-0.62) and oral cancer mortality by 29% (RR = 0.71, 95% CI: 0.69-0.73) at the 6-year follow-up in a screening scenario similar to the biennial screening in Taiwan, with a 55.1% attendance rate and 92.6% referral rate. The incremental effect in reducing advanced oral cancer was approximately 5% with a short 1-year screening frequency, and the corresponding reduction in mortality was, on average, 6.5%. The incremental reduction in advanced oral cancer per 10% increase in the compliance rate was 3% to 4%, while only 1% to 2% reduction was noted per 10% increase in the referral rate. The effectiveness of screening in reducing advanced oral cancer was 5% to 6% less when both betel quid chewing and alcohol drinking habits were present. Conclusion: Our computer simulation model demonstrated the effect of screening on the reduction in oral cancer mortality under various scenarios. The results provide screening policymakers with the necessary guidance to implement screening programs to save lives.

The health impact of human papillomavirus vaccination in the situation of primary human papillomavirus screening: A mathematical modeling study

BACKGROUND

Human papillomavirus (HPV) vaccination and the implementation of primary HPV screening in the Netherlands will lead to a lower cervical disease burden. For evaluation and further improvement of prevention, it is important to estimate the magnitude and timing of health benefits of current and alternative vaccination strategies such as vaccination of boys or adults.

METHODS AND FINDINGS

We evaluated the impact of the current girls-only vaccination program and alternative strategies on cervical disease burden among the first four vaccinated five-year birth cohorts, given the context of primary HPV screening. We integrated the existing microsimulation models STDSIM (HPV transmission model) and MISCAN-Cervix (cervical cancer screening model). Alternative vaccination strategies include: improved vaccination uptake, including routine boys vaccination, and offering adult vaccination at sexual health clinics. Our models show that the current vaccination program is estimated to reduce cervical cancers and cancer deaths by about 35% compared to primary HPV screening in the absence of vaccination. The number needed to vaccinate (NNV) to gain 1 life year is 45. The most efficient alternative vaccination strategies are: 1) improving coverage of girls to 80% (NNV = 42); and 2) routine vaccination for girls and boys at 80% coverage (incremental NNV = 155), with cervical cancer mortality reductions estimated at 50% and 60% respectively.

CONCLUSIONS

While the current program already substantially reduces cervical cancer incidence and mortality, prevention can be further improved by increasing vaccination uptake and extending vaccination to boys. As not all cervical cancer deaths will be prevented, screening participation should still be encouraged.

Assessment of Preventive Behavior for Cervical Cancer with the Health Belief Model

Introduction:

Cervical cancer is a leading cause of death in developing countries. However, taking regular Pap smears screening, one of the most effective screening tests, can reduce chance of cervical cancer remarkably. The first step in health education is choosing the right model, one of the best known being the Health Belief Model (HBM). Here, we evaluated different HBM factors with regard to cervical cancer preventive behavior in Fasa, Iran.

Materials and methods:

This cross-sectional study included 200 married women between the ages of 17 and 64 in Fasa during 2013. Participants were selected through stratified sampling from urban health centers. The questionnaire of the HBM included four sections and was filled out by interview. Data analysis was with SPSS 21, ANOVA and t-tests and Internal correlations between components of model were analyzed in terms of the Spearman Pearson correlation coefficient.

Results:

The mean age of the participants was 35.6±9.89 years. Some 52% had undergone a Pap test. The percentage values for participants’ knowledge and perceived susceptibility were 49.5% and 46%, respectively, considered as moderate. Perceived severity and benefits were good at 56.5% and 73%, respectively, while perceived barriers was moderate (46.5%). Also, 57.1% demonstrated a good self-efficacy and 61% good behavior.

Discussion:

We found that the most predictable factors for knowledge and behavior were age, income level, perceived benefits, perceived severity and self-efficacy according to the HBM. These factors should be taken into account for achieving acceptable preventive behaviors in health programs.

Simple but not simpler: a systematic review of Markov models for economic evaluation of cervical cancer screening

The aim of this study was to critically evaluate the quality of the models used in economic evaluations of screening strategies for cervical cancer prevention. We systematically searched multiple databases, selecting model-based full economic evaluations (cost-effectiveness analyses, cost-utility analyses, and cost-benefit analyses) of cervical cancer screening strategies. Two independent reviewers screened articles for relevance and performed data extraction. Methodological assessment of the quality of the models utilized formal checklists, and a qualitative narrative synthesis was performed. Thirty-eight articles were reviewed. The majority of the studies were conducted in high-income countries (82%, n=31). The Pap test was the most used screening strategy investigated, which was present in 86% (n=33) of the studies. Half of the studies (n=19) used a previously published Markov model. The deterministic sensitivity analysis was performed in 92% (n=35) of the studies. The mean number of properly reported checklist items was 9 out of the maximum possible 18. Items that were better reported included the statement of decision problem, the description of the strategies/comparators, the statement of time horizon, and information regarding the disease states. Compliance with some items of the checklist was poor. The Markov models for economic evaluation of screening strategies for cervical cancer varied in quality. The following points require improvement: 1) assessment of methodological, structural, heterogeneity, and parameter uncertainties; 2) model type and cycle length justification; 3) methods to account for heterogeneity; and 4) report of consistency evaluation (through calibration and validation methods).

Cost-effectiveness analysis of different types of human papillomavirus vaccination combined with a cervical cancer screening program in mainland China

BACKGROUND

China has a high prevalence of human papillomavirus (HPV) and a consequently high burden of disease with respect to cervical cancer. The HPV vaccine has proved to be effective in preventing cervical cancer and is now a part of routine immunization programs worldwide. It has also proved to be cost effective. This study aimed to assess the cost-effectiveness of 2-, 4-, and 9-valent HPV vaccines (hereafter, HPV2, 4 or 9) combined with current screening strategies in China.

METHODS

A Markov model was developed for a cohort of 100,000 HPV-free girls to simulate the natural history to HPV infection. Three recommended screening methods (1. liquid-based cytology test + HPV DNA test; 2. pap smear cytology test + HPV DNA test; 3. visual inspection with acetic acid) and three types of HPV vaccination program (HPV2/4/9) were incorporated into 15 intervention options, and the incremental cost-effectiveness ratio (ICER) was calculated to determine the dominant strategies. Costs, transition probabilities and utilities were obtained from a review of the literature and national databases. One-way sensitivity analyses and threshold analyses were performed for key variables in different vaccination scenarios.

RESULTS

HPV9 combined with screening showed the highest health impact in terms of reducing HPV-related diseases and increasing the number of quality-adjusted life years (QALYs). Under the current thresholds of willingness to pay (WTP, 3 times the per capita GDP or USD$ 23,880), HPV4/9 proved highly cost effective, while HPV2 combined with screening cost more and was less cost effective. Only when screening coverage increased to 60% ~ 70% did the HPV2 and screening combination strategy become economically feasible.

CONCLUSIONS

The combination of the HPV4/9 vaccine with current screening strategies for adolescent girls was highly cost-effective and had a significant impact on reducing the HPV infection-related disease burden in Mainland China.

Beware of Kinked Frontiers: A Systematic Review of the Choice of Comparator Strategies in Cost-Effectiveness Analyses of Human Papillomavirus Testing in Cervical Screening

OBJECTIVES

To systematically review the choice of comparator strategies in cost-effectiveness analyses (CEAs) of human papillomavirus testing in cervical screening.

METHODS

The PubMed, Web of Knowledge, and Scopus databases were searched to identify eligible model-based CEAs of cervical screening programs using human papillomavirus testing. The eligible CEAs were reviewed to investigate what screening strategies were chosen for analysis and how this choice might have influenced estimates of the incremental cost-effectiveness ratio (ICER). Selected examples from the reviewed studies are presented to illustrate how the omission of relevant comparators might influence estimates of screening cost-effectiveness.

RESULTS

The search identified 30 eligible CEAs. The omission of relevant comparator strategies appears likely in 18 studies. The ICER estimates in these cases are probably lower than would be estimated had more comparators been included. Five of the 30 studies restricted relevant comparator strategies to sensitivity analyses or other subanalyses not part of the principal base-case analysis. Such exclusion of relevant strategies from the base-case analysis can result in cost-ineffective strategies being identified as cost-effective.

CONCLUSIONS

Many of the CEAs reviewed appear to include insufficient comparator strategies. In particular, they omit strategies with relatively long screening intervals. Omitting relevant comparators matters particularly if it leads to the underestimation of ICERs for strategies around the cost-effectiveness threshold because these strategies are the most policy relevant from the CEA perspective. Consequently, such CEAs may not be providing the best possible policy guidance and lead to the mistaken adoption of cost-ineffective screening strategies.

Systematic review of model-based cervical screening evaluations

BACKGROUND

Optimising population-based cervical screening policies is becoming more complex due to the expanding range of screening technologies available and the interplay with vaccine-induced changes in epidemiology. Mathematical models are increasingly being applied to assess the impact of cervical cancer screening strategies.

METHODS

We systematically reviewed MEDLINE®, Embase, Web of Science®, EconLit, Health Economic Evaluation Database, and The Cochrane Library databases in order to identify the mathematical models of human papillomavirus (HPV) infection and cervical cancer progression used to assess the effectiveness and/or cost-effectiveness of cervical cancer screening strategies. Key model features and conclusions relevant to decision-making were extracted.

RESULTS

We found 153 articles meeting our eligibility criteria published up to May 2013. Most studies (72/153) evaluated the introduction of a new screening technology, with particular focus on the comparison of HPV DNA testing and cytology (n = 58). Twenty-eight in forty of these analyses supported HPV DNA primary screening implementation. A few studies analysed more recent technologies - rapid HPV DNA testing (n = 3), HPV DNA self-sampling (n = 4), and genotyping (n = 1) - and were also supportive of their introduction. However, no study was found on emerging molecular markers and their potential utility in future screening programmes. Most evaluations (113/153) were based on models simulating aggregate groups of women at risk of cervical cancer over time without accounting for HPV infection transmission. Calibration to country-specific outcome data is becoming more common, but has not yet become standard practice.

CONCLUSIONS

Models of cervical screening are increasingly used, and allow extrapolation of trial data to project the population-level health and economic impact of different screening policy. However, post-vaccination analyses have rarely incorporated transmission dynamics. Model calibration to country-specific data is increasingly common in recent studies.

Cost-effectiveness of Korea's National Cervical Cancer Screening Program

BACKGROUND

Cervical cancer, which is common in developing countries, is also a major health issue in Korea. Our aim was to evaluate the cost-effectiveness of Korea's National Cancer Screening Program (NCSP), implemented in 1999.

MATERIALS AND METHODS

The target population was Korean women 30 years or over who were invited to take part in the NCSP in 2002-2007. By merging NCSP records with Korean Central Cancer Registry data, patients diagnosed with cervical cancer who had been screened were assigned to a "screened group, " while patients diagnosed elsewhere were assigned to a "non-screened group. " Clinical outcomes were measured in terms of life-years saved (LYS), derived from 5-year mortality rates supplied by the Korean National Health Insurance Corporation and National Statistical Office. Direct and travel costs associated with screening were evaluated from the perspective of the payer, the NCSP.

RESULTS

A diagnosis via screening was associated with 2.30 LYS, and the incremental cost-effectiveness ratio (ICER) estimate for screening was 7,581,679 KW/LYS (6,727 USD/LYS). ICER estimates were lower for older patients (≥ 50 years) than younger patients (4,047,033 KW/ LYS vs 5,680,793 KW/LYS). The proportion of early-stage cancers detected was 16.3% higher in the screened group.

CONCLUSIONS

In light of Korea's per capita gross domestic product (32,272 USD in 2012), the current NCSP's incremental cost per LYS appears acceptable.

The clinical consequences of an ageing world and preventive strategies

Over the past century, the world has seen unprecedented declines in mortality rates, leading to an accelerated increase in the world population. This century will realise falling fertility rates alongside ageing populations. The 20th century was the century of population growth; the 21st century will be remembered as the century of ageing. Increase in life expectancy is one of the highest achievements of humankind; however, ageing and age-related disease is a mounting challenge for individuals, families, and for social, economic, and healthcare systems. Since healthy life expectancy has lagged behind the increase in life expectancy, the rise in morbidity will increase the burden on healthcare systems. Implementation of preventive health strategies to decrease, delay or prevent frailty, lung, breast and colon cancer, cardiovascular disease, metabolic syndrome, osteoporosis and osteopaenia, may increase health expectancy, and permit women to age gracefully and maintain independent living, without disability, for as long as possible.