An evaluation of liquid-based cytology and human papillomavirus testing within the UK cervical cancer screening programme

Rapid evaluation of service innovations in health and social care: key considerations

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (RSET: 16/138/17; BRACE: 16/138/31).

A systematic review of economic evaluations of cervical cancer screening methods

OBJECTIVE

The aims of this systematic review were to (1) identify primary- and model-based economic evaluations of cervical cancer screening methods and to (2) provide a contextual summary of valuation outcomes associated with three types of cervical cancer screening tests: visual inspection with acetic acid, human papillomavirus deoxyribonucleic acid, and Papanicolaou smear.

INTRODUCTION

Cervical cancer screening is an important public health priority with the potential to improve the detection of precancerous lesions in high-risk females for early intervention and disease prevention. Test performance and cost-effectiveness differ based on the specific screening method used across different platforms. There is a need to appraise existing economic evaluations of cervical cancer screening methods.

METHODS

This review considered primary-based and model-based full economic evaluations of cervical cancer screening methods. The evaluation methods of interest included cost-effectiveness analysis, cost-utility analysis, cost-minimization analysis, cost-benefit analysis, and cost-consequence analysis. We searched Scopus, PubMed, National Health Economic Evaluation Database (NH EED), Cochrane, and the Health Economic Evaluation Database for full economic evaluations of cancer screening methods. No formal date restrictions were applied. Model-based and primary-based full economic evaluations were included. A critical appraisal of included studies was performed by the main investigator, while a second independent reviewer assessed critical appraisal findings for any inconsistencies. Data were extracted using a standardised data extraction tool for economic evaluations. The ultimate outcomes of costs, effectiveness, benefits, and utilities of cervical cancer screening modalities were extracted from included studies, analysed, and summarised.

RESULTS

From a total of 671 screened studies, 44 studies met the study inclusion criteria. Forty-three studies were cost-effectiveness analyses, one study reported both cost-utility and cost-effectiveness outcomes, and another study reported cost utilities of cervical cancer screening methods only. Human papillomavirus (HPV) DNA testing was reported as a dominant stand-alone screening test by 14 studies, while five studies reported visual inspection with acetic acid (VIA) as a dominant stand-alone screening test. Primary HPV screening strategies were dominant in 21 studies, while three studies reported cytology-based screening strategies as the dominant screening method.

CONCLUSIONS

Existing evidence indicates that HPV-based and VIA testing strategies are cost-effective, but this is dependent on setting. Our review suggests the limited cost-effectiveness of cytology-based testing, which may be due in part to the need for specific infrastructures and human resources.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020212454 .

Cytomorphometry and morphology analysis of human papillomavirus type 16 in liquid-based cervical cytology samples

BACKGROUND

Human papillomavirus (HPV) is the main causal factor of cervical carcinoma. HPV 16 is one of the most prominent oncogenic types. We aimed to evaluate the cytomorphometric and morphological alterations caused by HPV 16 in liquid-based cytology (LBC).

METHODS

The Cobas 4800 HPV system was used for the detecting and typing HPV DNA in cervical specimens. In this study, 30 HPV 16 positive and 30 HPV 16 negative cervical samples were evaluated for micronuclei (MN), nonclassical cytologic abnormalities, and the nuclear-to-cytoplasmic ratio. Nuclear and cellular areas were evaluated using image analysis software and the nuclear-to-cytoplasm ratio was calculated. All analyses were performed blinded to the patients' HPV status. Statistical evaluation was carried out using the χ² and Fisher test; P-values < .05 were considered significant.

RESULTS

The frequencies of micronucleated cells and koilocytes were higher in the HPV 16 infected group (P < .05). Cells with perinuclear halo in control group were higher than the HPV 16 infected group (P < .05). The mean nuclear-to-cytoplasm ratio in HPV 16 patients was higher than the control value, but the difference was not statistically significant.

CONCLUSION

LBC can be used to detect morphological and morphometric changes. HPV 16 induces the formation of MN and koilocytosis. The evaluation of MN could provide additional information in monitoring genomic instability and of koilocytes could provide information about damage to the cytoskeleton filaments in HPV infection. Further studies are needed to investigate the effects of HPV-18 and other high-risk HPV types on the cell size and nucleus-to-cytoplasm ratio.

Clinical impact and cost-effectiveness of primary cytology versus human papillomavirus testing for cervical cancer screening in England

OBJECTIVES

In England, human papillomavirus (HPV) testing is to replace cytological screening by 2019-2020. We conducted a model-based economic evaluation to project the long-term clinical impact and cost-effectiveness of routine cytology versus HPV testing.

METHODS

An individual-based model of HPV acquisition, natural history, and cervical cancer screening was used to compare cytological screening and HPV testing with cytology triage for women aged 25-64 years (with either 3- or 5-year screening intervals for women aged under 50 years). The model was fitted to data from England's National Health Service Cervical Screening Programme. Both clinical and economic outcomes were projected to inform cost-effectiveness analyses.

RESULTS

HPV testing is likely to decrease annual cytology testing (by 2.76 million), cervical cancer incidence (by 290 cases), and health system costs (by £13 million). It may increase the number of colposcopies, although this could be reduced without leading to more cancers compared with primary cytology by increasing the interval between screens to 5 years. The impact in terms of quality-adjusted life-years (QALYs) depends on the quality of life weight given to colposcopies versus cancer.

CONCLUSIONS

England's move from cytology to HPV screening may potentially be life-saving and cost-effective. Cost-effectiveness can be improved further by extending the interval between screens or using alternative triage methods such as partial or full genotyping.

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).

A cluster randomised trial of strategies to increase cervical screening uptake at first invitation (STRATEGIC)

BACKGROUND

Falling participation by young women in cervical screening has been observed at a time that has seen an increase in the incidence of cervical cancer in the UK in women aged < 35 years. Various barriers to screening have been documented, including fear, embarrassment and inconvenience.

OBJECTIVES

To measure the feasibility, clinical effectiveness and cost-effectiveness of a range of interventions to increase the uptake of cervical screening among young women.

DESIGN

A cluster randomised trial based on general practices performed in two phases.

SETTING

Primary care in Greater Manchester and the Grampian region in Scotland.

PARTICIPANTS

Phase 1: 20,879 women receiving their first invitation for cervical screening. Phase 2: 10,126 women who had not attended by 6 months.

INTERVENTIONS

Phase 1: pre-invitation leaflet or not, and access to online booking (Manchester only). Phase 2: (1) vaginal self-sampling kits (SSKs) sent unrequested (n = 1141); or (2) offered on request (n = 1290); (3) provided with a timed appointment (n = 1629); (4) offered access to a nurse navigator (NN) (n = 1007); or (5) offered a choice between a NN or a SSK (n = 1277); and 3782 women in control practices.

MAIN OUTCOME MEASURES

Uplift in screening compared with control practices, cost-effectiveness of interventions, and the women's preferences explored in a discrete choice experiment.

RESULTS

The pre-invitation leaflet and offer of online booking were ineffective when compared with control practices at 3 months, 18.8% versus 19.2% [odds ratio (OR) 0.96, 95% confidence interval (CI) 0.88 to 1.06; p = 0.485] and 17.8% versus 17.2% (OR 1.02, 95% CI 0.87 to 1.20; p = 0.802), respectively. The uptake of screening at 3 months was higher among previously human papillomavirus (HPV)-vaccinated women than unvaccinated women, 23.7% versus 11% (OR 2.07, 95% CI 1.69 to 2.53; p < 0.001). Among non-attenders, the SSK sent intervention showed a statistically significant increase in uptake at 12 months post invitation, 21.3% versus 16.2% (OR 1.51, 95% CI 1.20 to 1.91; p = 0.001), as did timed appointments, 19.8% versus 16.2% (OR 1.41, 95% CI 1.14 to 1.74; p = 0.001). The offer of a NN, a SSK on request, and a choice between timed appointments and NN were ineffective. Overall, there was a gradual rather than prompt response, as demonstrated by uptake among control practices. A discrete choice experiment indicated that women invited who had not yet attended valued the attributes inherent in self-sampling. The health economic analysis showed that both timed appointments and unsolicited SSK sent were likely to be cost-effective at a cost per quality-adjusted life-year (QALY) gained of £7593 and £8434, respectively, if extended across the national 25-year-old cohort throughout the duration of screening. The certainty of these being cost-effective at a ceiling ratio of £20,000 per QALY gained was > 90%.

CONCLUSION

Women receiving their initial screening invitation frequently delay taking up the offer and the net impact of interventions was small. Timed appointments and SSKs sent to non-attenders at 6 months are likely to be a cost-effective means of increasing uptake and should be considered further. HPV vaccination in the catch-up programme was associated with an increased uptake of cervical screening. Future work should focus on optimising self-sampling in terms of age range, timing of offer for non-attenders and use of urine testing instead of vaginal samples.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN52303479.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 68. See the NIHR Journals Library website for further project information.

Present and future of cervical cancer prevention in Spain: a cost-effectiveness analysis

Human papillomavirus (HPV) vaccination within a nonorganized setting creates a poor cost-effectiveness scenario. However, framed within an organized screening including primary HPV DNA testing with lengthening intervals may provide the best health value for invested money. To compare the effectiveness and cost-effectiveness of different cervical cancer (CC) prevention strategies, including current status and new proposed screening practices, to inform health decision-makers in Spain, a Markov model was developed to simulate the natural history of HPV and CC. Outcomes included cases averted, life expectancy, reduction in the lifetime risk of CC, life years saved, quality-adjusted life years (QALYs), net health benefits, lifetime costs, and incremental cost-effectiveness ratios. The willingness-to-pay threshold is defined at 20 000&OV0556;/QALY. Both costs and health outcomes were discounted at an annual rate of 3%. A strategy of 5-year organized HPV testing has similar effectiveness, but higher efficiency than 3-year cytology. Screening alone and vaccination combined with cytology are dominated by vaccination followed by 5-year HPV testing with cytology triage (12 214&OV0556;/QALY). The optimal age for both ending screening and switching age from cytology to HPV testing in older women is 5 years later for unvaccinated than for vaccinated women. Net health benefits decrease faster with diminishing vaccination coverage than screening coverage. Primary HPV DNA testing is more effective and cost-effective than current cytological screening. Vaccination uptake improvements and a gradual change toward an organized screening practice are critical components for achieving higher effectiveness and efficiency in the prevention of CC in Spain.

Cost-effectiveness of strategies to increase cervical screening uptake at first invitation (STRATEGIC)

Objective To assess the cost-effectiveness of strategies to increase cervical cancer screening uptake at first invitation (STRATEGIC trial). Methods We performed an economic analysis alongside the STRATEGIC trial, comparing each of seven novel interventions for improving cervical screening uptake with control general practices in Greater Manchester and Grampian (United Kingdom). A template was developed to measure the intervention costs. Trial estimates of screening uptake were combined with data from the literature to estimate healthcare costs of each intervention. The added lifetime costs and quality adjusted life years (QALYs) of attending cervical screening were estimated by a systematic literature review, with relevant results pooled and weighted by study quality. Trial results and estimated lifetime costs and benefits of screening were then combined in a decision analytic model, giving an incremental cost per QALY gained for each intervention. Uncertainty was addressed in probabilistic and univariate sensitivity analyses. Results Intervention costs per screening round per woman attending varied from about £1.20 (2014 UK) for the nurse navigator intervention to £62 for the unrequested HPV self-sampler kit. The meta-analysis revealed a lifetime discounted benefit from screening of 0.043 QALYs per woman attending, at an additional lifetime discounted cost of £234. The incremental cost per QALY gained in all interventions was below £13,000. Probabilistic sensitivity analyses suggested that only unrequested self-sampling and timed appointments have a high probability of being cost-effective. Conclusions Unrequested self-sampling and timed appointments are likely to be cost-effective interventions. Further research is required on the duration of effects and on implementing combinations of interventions.

Cost-Effectiveness of Primary HPV Testing, Cytology and Co-testing as Cervical Cancer Screening for Women Above Age 30 Years

BACKGROUND

Cervical cancer screening guidelines for women aged ≥30 years allow for co-testing or primary cytology testing. Our objective was to determine the test characteristics and costs associated with Cytology, HPV and Co-testing screening strategies.

MAIN METHODS

Retrospective cohort study of women undergoing cervical cancer screening with both cytology and HPV (Hybrid Capture 2) testing from 2004 to 2010 in an integrated health system. The electronic health record was used to identify women aged ≥30 years who had co-testing. Unsatisfactory or unavailable test results and incorrectly ordered tests were excluded. The main outcome was biopsy-proven cervical intraepithelial neoplasia grade 3 or higher (CIN3+).

KEY RESULTS

The final cohort consisted of 99,549 women. Subjects were mostly white (78.4 %), married (70.7 %), never smokers (61.3 %) and with private insurance (86.1 %). Overall, 5121 (5.1 %) tested positive for HPV and 6115 (6.1 %) had cytology ≥ ASCUS; 1681 had both and underwent colposcopy and 310 (0.3 %) had CIN3+. Sensitivity for CIN3+ was 91.9 % for Primary Cytology, 99.4 % for Co-testing, and 94.8 % for Primary HPV; specificity was 97.3 % for Co-testing and Primary Cytology and 97.9 % for Primary HPV. Over a 3-year screening interval, Primary HPV detected more cases of CIN3+ and was less expensive than Primary Cytology. Co-testing detected 14 more cases of CIN3+ than Primary HPV, but required an additional 100,277 cytology tests and 566 colposcopies at an added cost of $2.38 million, or $170,096 per additional case detected.

CONCLUSIONS

Primary HPV was more effective and less expensive than Primary Cytology. Primary HPV screening appears to represent a cost-effective alternative to Co-testing.

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.

How many cervical cancer cases can potentially be prevented using a more sensitive screening test at young age?

The human papilloma virus (HPV) DNA test has higher sensitivity than cytology for cervical cancer screening. Therefore, cervical cancer cases that are missed by cytology could potentially be identified if we use primary HPV testing. Studies showed that HPV screening is the preferred primary test at age 35 and over. Given the high prevalence of harmless HPV infections, the use of HPV testing at younger age is less obvious. The number of cancers in young age is often mentioned to indicate the possible benefits of a more sensitive test. We actually estimated the proportion of those cases that is potentially preventable in The Netherlands by the use of a more sensitive screen-test at the first screening age 30, given that the more sensitive test is used at age 35 and over. We analysed the screening history of women diagnosed with cervical cancer in the period 2004 to March 2009, using data from the Dutch National Pathology Registry. Only 15-30% (two to four cases per 100,000 women) of the cases was preceded by negative cytology under age 35 and therefore could have been prevented by a more sensitive test at age 30. The lower the screening coverage and the shorter the screening interval in those screened at young age, the smaller the gain of a more sensitive test. So, as long as the current screening pattern is not changed, the majority of the cervical cancer cases at young age would still occur even when applying a more sensitive test at the younger ages.

Cost effectiveness of human papillomavirus test of cure after treatment for cervical intraepithelial neoplasia in England: economic analysis from NHS Sentinel Sites Study

OBJECTIVES

To evaluate the cost effectiveness of human papillomavirus testing after treatment for cervical intraepithelial neoplasia (CIN).

DESIGN

Economic analysis using a Markov modelling approach to combine cost and epidemiological data from the NHS Sentinel Sites Study with data from previous studies of post-treatment recurrence rates.

SETTING

English NHS Cervical Cancer Screening Programme.

INTERVENTIONS

Management guidelines after treatment of CIN involving annual cytology follow-up for 10 years, compared with alternative protocols using the human papillomavirus test to reduce the amount of post-treatment surveillance.

MAIN OUTCOME MEASURES

Cases of underlying CIN3+ averted at 10 years and costs per 1000 women treated.

RESULTS

Model predictions indicated that, at observed levels of compliance with post-treatment recommendations, management with only cytological follow-up would result in 29 residual cases of recurrent CIN3+ by 10 years and would cost £358,222 (€440,426; $574,910) (discounted) per 1000 women treated. Implementation of human papillomavirus test of cure in cytologically negative women according to the sentinel sites protocol would avert an additional 8.4 cases of CIN 3+ and reduce costs by £9388 per 1000 women treated.

CONCLUSIONS

Human papillomavirus test of cure would be more effective and would be cost saving compared with cytology only follow-up. The results of this evaluation support the full scale implementation of human papillomavirus test of cure after treatment of CIN within the NHS Cervical Screening Programme.

Cost and logistics of alternative roll-out options for implementing human papillomavirus testing as a triage in cervical screening: results of the sentinel sites study

Background:

Previous studies have indicated that human papillomavirus (HPV) testing as a triage for managing equivocal cytology is cost-effective. The aim of this study was to assess the costs of alternative roll-out options.

Methods:

Detailed cost estimates were collected from six laboratories where HPV triage had been implemented. Costs were assessed for the two different service delivery models that were implemented; a ‘hub and spoke model’ of central HPV testing in a microbiology laboratory with separate cytology laboratories, and an ‘integrated model’ where HPV testing was conducted within the cytology laboratory.

Results:

Comparison of alternative delivery models indicated that setting up HPV processing within existing cytology laboratory, i.e., an ‘integrated cytology/HPV laboratory’ generated savings in staff time amounting to between £2.54 and 4.86 per sample processed. Running full HPV testing batches was also an important consideration. For full batches to be run on a twice weekly basis requires having no more than two laboratories per Strategic Health Authority.

Conclusions:

To be cost-efficient, and to meet turn-around times, HPV testing needs to be conducted at integrated cytology/HPV testing centres with sufficient throughput to run full batches of HPV tests.

Cost-effectiveness of cervical cancer screening with primary human papillomavirus testing in Norway

Background:

New screening technologies and vaccination against human papillomavirus (HPV), the necessary cause of cervical cancer, may impact optimal approaches to prevent cervical cancer. We evaluated the cost-effectiveness of alternative screening strategies to inform cervical cancer prevention guidelines in Norway.

Methods:

We leveraged the primary epidemiologic and economic data from Norway to contextualise a simulation model of HPV-induced cervical cancer. The current cytology-only screening was compared with strategies involving cytology at younger ages and primary HPV-based screening at older ages (31/34+ years), an option being actively deliberated by the Norwegian government. We varied the switch-age, screening interval, and triage strategies for women with HPV-positive results. Uncertainty was evaluated in sensitivity analysis.

Results:

Current cytology-only screening was less effective and more costly than strategies that involve switching to primary HPV testing in older ages. For unvaccinated women, switching at age 34 years to primary HPV testing every 4 years was optimal given the Norwegian cost-effectiveness threshold ($83 000 per year of life saved). For vaccinated women, a 6-year screening interval was cost-effective. When we considered a wider range of strategies, we found that an earlier switch to HPV testing (at age 31 years) may be preferred.

Conclusions:

Strategies involving a switch to HPV testing for primary screening in older women is expected to be cost-effective compared with current recommendations in Norway.

Primary screening for human papillomavirus compared with cytology screening for cervical cancer in European settings: cost effectiveness analysis based on a Dutch microsimulation model

OBJECTIVES

To investigate, using a Dutch model, whether and under what variables framed for other European countries screening for human papillomavirus (HPV) is preferred over cytology screening for cervical cancer, and to calculate the preferred number of examinations over a woman's lifetime.

DESIGN

Cost effectiveness analysis based on a Dutch simulation model. Base case analyses investigated the cost effectiveness of more than 1500 different screening policies using the microsimulation model. Subsequently, the policies were compared for five different scenarios that represent different possible scenarios (risk of cervical cancer, previous screening, quality associated test characteristics, costs of testing, and prevalence of HPV).

SETTING

Various European countries.

POPULATION

Unvaccinated women born between 1939 and 1992.

MAIN OUTCOME MEASURES

Optimal screening strategy in terms of incremental cost effectiveness ratios (costs per quality adjusted life years gained) compared with different cost effectiveness thresholds, for two levels of sensitivity and costs of the HPV test.

RESULTS

Primary HPV screening was the preferred primary test over the age of 30 in many considered scenarios. Primary cytology screening was preferred only in scenarios with low costs of cytology and in scenarios with a high prevalence of HPV in combination with high costs of HPV testing.

CONCLUSIONS

Most European countries should consider switching from primary cytology to HPV screening for cervical cancer. HPV screening must, however, only be implemented in situations where screening is well controlled.

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

INTRODUCTION

As the effectiveness of cytology-based screening programme for cervical cancer in mortality reduction has reached a plateau, various preventive strategies have been considered, including intensive Pap smear screening and the supplemental use of human papillomavirus (HPV) DNA test or HPV vaccination. Cost and effectiveness of these various preventive strategies are therefore of great concern for health policy makers.

OBJECTIVE

We intended to assess whether the combination of HPV DNA testing or HPV vaccination with Pap smear screening programme or the sole annual Pap smear screening is more effective and cost-effective in prevention of cervical cancer than the existing triennial Pap smear screening programme.

METHODS

A Markov decision model was constructed to compare total costs and effectiveness between different preventive strategies (including annual Pap smear, HPV DNA testing or HPV vaccination together with Pap smear screening programme) as opposed to the triennial Pap smear screening alone (the comparator). Probabilistic cost-effectiveness (C-E) analysis was adopted to plot a series of simulated incremental C-E ratios scattered over C-E plane and also to yield the acceptability curve for different comparisons of strategies. The threshold of vaccine cost and the influence of attendance rate were also investigated.

RESULTS

Compared with triennial Pap smear screening programme, most of preventive strategies cost more but gain additional life years (quadrant I of C-E plane) except HPV DNA testing with Pap smear every 5 years dominated by triennial Pap smear screening programme. The most cost-effective strategy was annual Pap smear (incremental C-E ratio = $31 698), followed by HPV DNA testing with Pap smear every 3 years ($36 627), and vaccination programme with triennial Pap smear screening ($44 688) with the corresponding cost-effective probabilities by the acceptability curve being 65.52%, 52.08% and 35.84% given the threshold of $40 000 of willingness to pay. Vaccination combined with triennial Pap smear would be as cost-effective as annual Pap smear provided the cost of vaccination was lowered to $250 per full course of injection.

CONCLUSIONS

Among various preventive strategies annual Pap smear screening programme is still the most cost-effective and additional HPV DNA testing is a cost-effective choice under a reasonable threshold of willingness to pay. Vaccination programme in combination with triennial screening would be cost-effective if vaccine cost can be greatly reduced in a large economic scale.

Cost-effectiveness of 21 alternative cervical cancer screening strategies

OBJECTIVES

The aim of this study is to assess the cost-effectiveness of 21 alternative cervical cancer screening (CCS) strategies.

METHODS

A cohort simulation model was developed to determine from a health systems perspective the cost-effectiveness of the 21 alternative CCS strategies that incorporated combinations of Papanicolaou's smear test (PAP), liquid-based cytology (LBC) or human papillomavirus deoxyribonucleic acid (HPV-DNA) testing. The model was calibrated to categorize total costs into four budgetary authorities: testing, physician, inpatient, and outpatient services. Within each category, alternative screening strategies were contrasted in terms of their cost impacts and the percent change calculated within each category. Epidemiologic data and costs were derived from administrative health databases. Estimates of test characteristics and quality-adjusted life years (QALYs) were derived from available literature.

RESULTS

Three-year screening with PAP and HPV-DNA triage testing for women older than 30 years of age (3-year PAP+HPV+PAP-age) is less costly and more effective saving $16,078 per additional QALY gained. Although there was an associated net cost decrease of 4.2% driven by a reduction in testing and physician costs of 22.1% and 18.6%, respectively, there is a cost increase of 0.8% and 27.7% in inpatient and outpatient services, respectively.

CONCLUSION

There is economic evidence to support adopting 3-year PAP+HPV+PAP-age. Budgetary resources can potentially be shifted from testing and physician services to fund the additional resource requirements for inpatient and outpatient services.

Options for managing low grade cervical abnormalities detected at screening: cost effectiveness study

OBJECTIVE

To estimate the cost effectiveness of alternative methods of managing low grade cervical cytological abnormalities detected at routine screening. Design Cost analysis within multicentre individually randomised controlled trial.

SETTING

Grampian, Tayside, and Nottingham.

PARTICIPANTS

4201 women with low grade abnormalities.

INTERVENTIONS

Cytological surveillance or referral to colposcopy for biopsy and recall if necessary or referral to colposcopy with immediate treatment based on colposcopic appearance.

MAIN OUTCOME MEASURES

Data on resource use collected from participants throughout the duration of the trial (36 months), enabling the estimation of both the direct (health care) and indirect (time and travel) costs of management. Quality of life assessed at recruitment and at 12, 18, 24, and 30 months, using the EQ-5D instrument. Economic outcomes expressed as costs per case of cervical intraepithelial neoplasia (grade II or worse) detected, by trial arm, as confirmed at exit, and cost utility ratios (cost per quality adjusted life year (QALY) gained) for the three pairwise comparisons of trial arms.

RESULTS

The mean three year discounted costs of surveillance, immediate treatment, and biopsy and recall were pound150.20 (euro177, $249), pound240.30 (euro283, $415), and pound241.10 (euro284, $4000), respectively, viewed from the health service perspective. From the social perspective, mean discounted costs were pound204.40 (euro241, $339), pound339.90 (euro440, $563), and pound327.50 (euro386, $543), respectively. Estimated at the means, the incremental cost effectiveness ratios indicated that immediate treatment was dominated by the other two management methods, although it did offer the lowest cost per case of cervical intraepithelial neoplasia detected and treated. The pronounced skews in the distributions indicated that probabilistic uncertainty analysis would offer more meaningful estimates of cost effectiveness. The observed differences in the cost effectiveness ratios between trial arms were not significant.

CONCLUSION

Judged within the time frame of the TOMBOLA evaluation, there is no compelling economic reason to favour any one follow-up method over either of the others.

TRIAL REGISTRATION

ISRCTN 34841617.

The health and economic impact of cervical cancer screening and human papillomavirus vaccination in kidney transplant recipients

BACKGROUND

The risk of cervical cancer in women who are kidney transplant recipients is increased, but little is known about the effectiveness of screening and human papillomavirus (HPV) vaccination in this group of women. We sought to determine the cost effectiveness of annual screening for cervical cancers using conventional cytology, liquid-based cytology (LBC), and pretransplant HPV vaccination in kidney transplant recipients.

METHODS

Three deterministic Markov models were developed to compare the costs and health outcomes in a cohort of women (n=1000) with kidney transplants aged 18 to 69 who underwent annual screening using conventional cytology, LBC, and HPV vaccination in HPV naïve women.

RESULTS

After a screening period of 50 years, the incremental benefits of screening using conventional cytology compared with no screening were 0.05 life years saved (LYS) (18.2 days of lives saved), the incremental costs were $608, giving an incremental cost-effectiveness ratio of $12,160 per LYS. Compared with conventional cytology alone, the incremental cost-effectiveness ratios of annual screening using LBC and HPV vaccination before transplantation (assuming nonwaning efficacy) were $127,000 and $152,333 per LYS, respectively.

CONCLUSION

The recommended policy of annual screening using conventional cytology is cost effective. The replacement of conventional cytology with LBC is likely to provide minimal survival benefits but considerable costs. Assuming the reported trial-based vaccine efficacy in HPV naïve women, a program of HPV vaccination before kidney transplantation is unlikely to be cost effective. Additional data about the long-term efficacy and safety of HPV vaccination is required before it should be included as standard care of renal transplant recipients.

Calibration methods used in cancer simulation models and suggested reporting guidelines

Increasingly, computer simulation models are used for economic and policy evaluation in cancer prevention and control. A model's predictions of key outcomes, such as screening effectiveness, depend on the values of unobservable natural history parameters. Calibration is the process of determining the values of unobservable parameters by constraining model output to replicate observed data. Because there are many approaches for model calibration and little consensus on best practices, we surveyed the literature to catalogue the use and reporting of these methods in cancer simulation models. We conducted a MEDLINE search (1980 through 2006) for articles on cancer-screening models and supplemented search results with articles from our personal reference databases. For each article, two authors independently abstracted pre-determined items using a standard form. Data items included cancer site, model type, methods used for determination of unobservable parameter values and description of any calibration protocol. All authors reached consensus on items of disagreement. Reviews and non-cancer models were excluded. Articles describing analytical models, which estimate parameters with statistical approaches (e.g. maximum likelihood) were catalogued separately. Models that included unobservable parameters were analysed and classified by whether calibration methods were reported and if so, the methods used. The review process yielded 154 articles that met our inclusion criteria and, of these, we concluded that 131 may have used calibration methods to determine model parameters. Although the term 'calibration' was not always used, descriptions of calibration or 'model fitting' were found in 50% (n = 66) of the articles, with an additional 16% (n = 21) providing a reference to methods. Calibration target data were identified in nearly all of these articles. Other methodological details, such as the goodness-of-fit metric, were discussed in 54% (n = 47 of 87) of the articles reporting calibration methods, while few details were provided on the algorithms used to search the parameter space. Our review shows that the use of cancer simulation modelling is increasing, although thorough descriptions of calibration procedures are rare in the published literature for these models. Calibration is a key component of model development and is central to the validity and credibility of subsequent analyses and inferences drawn from model predictions. To aid peer-review and facilitate discussion of modelling methods, we propose a standardized Calibration Reporting Checklist for model documentation.

Trade-offs in cervical cancer prevention: balancing benefits and risks

BACKGROUND

New screening and vaccination technologies will provide women with more options for cervical cancer prevention. Because the risk of cervical cancer diminishes with effective routine screening, women may wish to consider additional attributes, such as the likelihood of false-positive results and diagnostic procedures for mild abnormalities likely to resolve without intervention in their screening choices.

METHODS

We used an empirically calibrated simulation model of cervical cancer in the United States to assess the benefits and potential risks associated with prevention strategies differing by primary screening test, triage test for abnormal results (cytologic testing, human papillomavirus [HPV] DNA test), and screening frequency. Outcomes included colposcopy referrals, cervical intraepithelial neoplasia (CIN) types 1 and 2 or 3, lifetime cancer risk, and quality-adjusted life expectancy.

RESULTS

Across strategies, colposcopy referrals and diagnostic workups varied 3-fold, although diagnostic rates of CIN 2 or 3 were similar and 95% of positive screening test results were for mild abnormalities likely to resolve on their own. For a representative group of a thousand 20-year-old women undergoing triennial screening for 10 years, we expect 1038 colposcopy referrals (7 CIN 2 or 3 diagnoses) from combined cytologic and HPV DNA testing and fewer than 200 referrals (6-7 CIN 2 or 3 diagnoses) for strategies that use triage testing. Similarly, for a thousand 40-year-old women, combined cytologic and HPV DNA testing led to 489 referrals (9 CIN 2 or 3), whereas alternative strategies resulted in fewer than 150 referrals (7-8 CIN 2 or 3). Using cytologic testing followed by triage testing in younger women minimizes both diagnostic workups and positive HPV test results, whereas in older women diagnostic workups are minimized with HPV DNA testing followed by cytologic triage testing.

CONCLUSIONS

Clinically relevant information highlighting trade-offs among cervical cancer prevention strategies allows for inclusion of personal preferences into women's decision making about screening and provides additional dimensions to the construction of clinical guidelines.

Long-term clinical impact of introducing a human papillomavirus 16/18 AS04 adjuvant cervical cancer vaccine in Spain

BACKGROUND

Human papillomavirus (HPV) epidemiology and screening practices vary considerably between countries and specific analyses are required to estimate the impact of HPV vaccination. This study aimed to predict the clinical benefits of introducing a bivalent HPV16/18 vaccine in Spain, where the cervical cancer (CC) incidence is 10.3 per 100 000.

METHODS

A Markov model based upon the natural history of HPV and CC was developed to simulate transitions between health states, in the presence of specific screening programmes. Published data were used to reflect the Spanish situation in terms of epidemiological characteristics, screening and treatment practices. Calibration consisted of varying disease progression rates within established ranges until model predictions matched observed epidemiological data. The clinical impact of vaccinating a cohort of 12-year-old girls against HPV was assessed over their lifetime using the calibrated model.

RESULTS

Vaccination of all 12-year-old girls would result in a reduction of 75% (from 0.32% to 0.08%) in the prevalence of high-grade precancerous lesions due to oncogenic HPV, and a 79% reduction in both CC cases (from 1745 to 365) and CC deaths (from 417 to 86). Assuming a vaccine coverage of 80%, the number of CC cases and deaths would decrease by 63%. Vaccination could also substantially reduce the number of screening tests and treatments required for cervical dysplasia.

CONCLUSION

Our model was successfully adapted to the Spanish epidemiological environment, screening and treatment practices and predicted a substantial long-term benefit of HPV vaccination despite a low HPV prevalence in Spain.

Cost-effectiveness of primarily human papillomavirus–based cervical cancer screening in settings with currently established Pap screening: A systematic review commissioned by the German Federal Ministry of Health

Objectives:The aim of this study was to summarize the current evidence for the cost-effectiveness of primarily human papillomavirus (HPV) -based cervical cancer screening in settings with already established Papanicolaou test (Pap) programs. Emphasis was placed on the German situation with annual Pap screening.

Methods:Medical, economic, and health technology assessment (HTA) databases were systematically searched for cost-effectiveness studies comparing HPV to Pap screening. Study data were extracted, standardized, and summarized in cost-effectiveness plots contrasting HPV strategies to Pap screening with 1-, 2-, 3-, and 5-years interval. For each Pap setting, the likelihood of cost-effective HPV screening was assessed depending on willingness-to-pay.

Results:We reviewed twelve decision-analytic cost-effectiveness models. Study results showed wide variation due to methodical heterogeneity. Data synthesis revealed that the cost-effectiveness of HPV screening depends on the interval of the established Pap screening strategy. In comparison with Pap screening every 2 years, only 25 percent of the HPV-based screening strategies were cost-effective. However, in comparison with Pap screening every 1, 3, or 5 years, 83 percent, 55 percent, and 92 percent of HPV screening strategies were cost-effective, respectively. Results for settings with annual Pap screening are based on models assuming 100 percent screening coverage.

Conclusions:The introduction of HPV-based screening programs is cost-effective if the screening interval of the established Pap program exceeds 2 years. In settings with biennial Pap screening, introduction of HPV-based screening is unlikely to be cost-effective. Results also suggest cost-effectiveness of HPV-based screening in settings with annual Pap screening; however, this finding should be confirmed under realistic screening adherence assumptions.

Cost-effectiveness of cervical cancer screening with human papillomavirus DNA testing and HPV-16,18 vaccination

BACKGROUND

The availability of human papillomavirus (HPV) DNA testing and vaccination against HPV types 16 and 18 (HPV-16,18) motivates questions about the cost-effectiveness of cervical cancer prevention in the United States for unvaccinated older women and for girls eligible for vaccination.

METHODS

An empirically calibrated model was used to assess the quality-adjusted life years (QALYs), lifetime costs, and incremental cost-effectiveness ratios (2004 US dollars per QALY) of screening, vaccination of preadolescent girls, and vaccination combined with screening. Screening varied by initiation age (18, 21, or 25 years), interval (every 1, 2, 3, or 5 years), and test (HPV DNA testing of cervical specimens or cytologic evaluation of cervical cells with a Pap test). Testing strategies included: 1) cytology followed by HPV DNA testing for equivocal cytologic results (cytology with HPV test triage); 2) HPV DNA testing followed by cytology for positive HPV DNA results (HPV test with cytology triage); and 3) combined HPV DNA testing and cytology. Strategies were permitted to switch once at age 25, 30, or 35 years.

RESULTS

For unvaccinated women, triennial cytology with HPV test triage, beginning by age 21 years and switching to HPV testing with cytology triage at age 30 years, cost $78,000 per QALY compared with the next best strategy. For girls vaccinated before age 12 years, this same strategy, beginning at age 25 years and switching at age 35 years, cost $41,000 per QALY with screening every 5 years and $188,000 per QALY screening triennially, each compared with the next best strategy. These strategies were more effective and cost-effective than screening women of all ages with cytology alone or cytology with HPV triage annually or biennially.

CONCLUSIONS

For both vaccinated and unvaccinated women, age-based screening by use of HPV DNA testing as a triage test for equivocal results in younger women and as a primary screening test in older women is expected to be more cost-effective than current screening recommendations.

Baseline human papillomavirus status of women with abnormal smears in cervical screening: a 5-year follow-up study in the Netherlands

OBJECTIVE

To determine in a screening population the human papillomavirus (HPV) status in those with cytological abnormalities and to evaluate the presence of high-risk (HR) HPV with a minimum of 5-year follow up.

DESIGN

Retrospective examination of HPV status on prospectively collected and cytologically screened cervical smears.

SETTING

Canisius-Wilhelmina Hospital in Nijmegen, The Netherlands.

POPULATION

Three hundred and fifty-seven women aged 30-60 years, from the population screened.

METHODS

Three hundred and fifty-seven women with borderline or higher cytological abnormalities were retrospectively examined for HPV with DNA microarray typing. Follow up was through the nationwide Dutch Pathology database (PALGA).

MAIN OUTCOME MEASURES

For the cytological abnormalities, the CISOE-A classification was used. HPV was scored as negative or positive. In case of positive HPV polymerase chain reaction, the HPV genotype was determined. The occurrence of cervical intraepithelial neoplasia lesions of grade 3 or higher was considered as endpoint for follow up.

RESULTS

The majority of the women with borderline cytology in this study were HPV negative (87%). Among the HPV-positive women in borderline cytology group, 74% had HR-HPV or probable high-risk types. The overall percentage of HR-HPV types increased with progressive cytological abnormalities. The cytological classifications of borderline dyskaryosis and moderate dyskaryosis contain all types of HPVs, e.g. low risk, HR and unknown risk. The samples with severe dyskaryosis or higher contain only HR types. The negative predictive value for HR-HPV typing in the group with borderline cytological abnormalities is more than 99%.

CONCLUSIONS

In cervical screening with an interval of 5 years, HPV can be reliably used as triage point in cases of borderline cytological abnormalities.

A public health approach to cervical cancer control: considerations of screening and vaccination strategies

Cervical cancer remains a leading cause of cancer death among women living in low-resource settings. In the last 3 decades, cytologic screening has -in theory -been available and yet more than 6 million women have died of this preventable disease. The necessary resources, infrastructure, and technological expertise, together with the need for repeated screenings at regular intervals, make cytologic screening difficult to implement in poor countries. As noncytologic approaches for the detection of HPV, simple visual screening methods for anogenital lesions caused by HPV, and the availability of an HPV-16/18 vaccine will enhance the linkage between screening and treatment, multiple factors will need to be considered when designing new, or modifying existing prevention strategies. Countryspecific decisions regarding the best strategy for cervical cancer control will need to rely on data from many sources and take into account complex epidemiologic, economic, social, political, and cultural factors, and be made despite uncertainty and incomplete information. A rigorous decision analytic approach using computerbased modeling methods enables linkage of the knowledge gained from empirical studies to real-world situations. This chapter provides an introduction to these methods, reviews lessons learned from cost-effectiveness analyses of cervical cancer screening in developed and developing countries, and emphasizes important qualitative themes to consider in designing cervical cancer prevention policies.

Estimating the long-term impact of a prophylactic human papillomavirus 16/18 vaccine on the burden of cervical cancer in the UK

To predict the public health impact on cervical disease by introducing human papillomavirus (HPV) vaccination in the United Kingdom, we developed a mathematical model that can be used to reflect the impact of vaccination in different countries with existing screening programmes. Its use is discussed in the context of the United Kingdom. The model was calibrated with published data. The impact of vaccination on cervical cancer and deaths, precancerous lesions and screening outcomes were estimated for a vaccinated cohort of 12-year-old girls, among which it is estimated that there would be a reduction of 66% in the prevalence of high-grade precancerous lesions and a 76% reduction in cervical cancer deaths. Estimates for various other measures of the population effects of vaccination are also presented. We concluded that it is feasible to forecast the potential effects of HPV vaccination in the context of an existing national screening programme. Results suggest a sizable reduction in the incidence of cervical cancer and related deaths. Areas for future research include investigation of the beneficial effects of HPV vaccination on infection transmission and epidemic dynamics, as well as HPV-related neoplasms in other sites.

United Kingdom cervical cancer screening and the costs of time and travel

OBJECTIVES

The aim of this study was to estimate the time and travel costs generated by women when attending for Papanicolaou (Pap) smear tests or colposcopy appointments in the United Kingdom, both absolutely and relative to the health service cost of the national cervical cancer screening programs.

METHODS

Data were obtained from questionnaires completed by two samples of women participating in a three-center trial of management of low-grade abnormalities detected by screening (n = 1,106 for Pap smears and n = 1,203 for colposcopy appointments). Women were 20 to 59 years of age and resident in Grampian or Tayside, Scotland, or Nottingham, England. Questionnaire data were supplemented with sociodemographic information previously collected at the time of recruitment to the trial.

RESULTS

The mean total time and travel costs per attendance at a smear test and at a colposcopy appointment were estimated to be 9.2 pounds and 27.4 pounds, respectively, averaged across the three trial areas (valued at 2002 prices). Statistically significant intercenter disparities in time and travel costs were identified, particularly with respect to colposcopy appointments. For these, time and travel costs in Nottingham were substantially less than those in Grampian and Tayside (22.9 pounds, 30.2 pounds, and 32.1 pounds, respectively). Time and travel costs amount to 26 and 33 percent, approximately, over and above the direct health service costs of the English and Scottish screening programs, respectively.

CONCLUSIONS

The time and travel costs associated with participation in the UK cervical cancer screening programs are substantial and are not spatially uniform across the country.

Chapter 19: Cost-effectiveness of cervical cancer screening

In the last two decades, computer-based models of cervical cancer screening have been used to evaluate the cost-effectiveness of different secondary prevention policies. Analyses in countries with existing screening programs have focused on identifying the optimal screening interval, ages for starting and stopping screening, and consideration of enhancements to conventional cytology, such as human papillomavirus (HPV)-DNA testing as a triage for equivocal results or as a primary screening test for women over the age of 30. Analyses in resource-poor settings with infrequent or no screening have focused on strategies that enhance the linkage between screening and treatment, consider noncytologic alternatives such as HPV-DNA testing, and target women between the ages of 35 and 45 for screening one, two, or three times per lifetime. Despite differences in methods and assumptions, this paper identifies the qualitative themes that are consistent among studies, and highlights important methodological challenges and high-priority areas for further work.

Evaluation of cervical screening strategies with adjunct high-risk human papillomavirus testing for women with borderline or mild dyskaryosis

The management of women with a smear read as borderline/mild dyskaryosis (BMD) found by cervical cancer screening is still under discussion as only few of these cases are associated with high-grade lesions. To determine the optimal screening strategy for these women, a simulation model of cervical cancer development was used that is based on high-risk human papillomavirus (hrHPV) infection. The current strategy of repeat cytological testing at 6 and 18 months after BMD was compared to strategies with adjunct hrHPV testing. Calculations were done for both conventional and liquid-based cytology as the primary screening tool. In comparison to current screening, adjunct hrHPV testing was more effective in preventing cancer and more woman-friendly (reduction in colposcopy referrals with outcome < cervical intraepithelial neoplasia (CIN2) of up to 56% and in repeat smears of 30-100%). In combination with conventional cytology, cost-effective strategies were the ones in which a sample for high-risk human papillomavirus (hrHPV) testing is collected at a return visit within 1 month or in which hrHPV testing is restricted to repeat smears taken at 6 and 18 months. For these strategies, co-collection of samples for hrHPV testing at baseline is not necessary which has organizational and cost advantages. In combination with liquid-based cytology, it was cost-effective to perform a reflex hrHPV test at baseline from the liquid-based specimen. Liquid-based screening was more effective than conventional screening, but annual diagnosis costs were euro5 million higher (population size 16 million). In conclusion, our calculations indicate that implementation of hrHPV testing for the management of women with borderline or mild dyskaryosis (BMD) is feasible both in settings where conventional and liquid-based cytology is current practice.

Lifetime effects, costs, and cost effectiveness of testing for human papillomavirus to manage low grade cytological abnormalities: results of the NHS pilot studies

OBJECTIVES

To predict the incremental lifetime effects, costs, and cost effectiveness of using human papillomavirus testing to triage women with borderline or mildly dyskaryotic cervical smear results for immediate colposcopy.

DESIGN

Modelling study.

SETTING

Three centres participating in NHS pilot studies, United Kingdom. Population Women aged 25-64 with borderline or mildly dyskaryotic cervical smear results.

INTERVENTIONS

Screening using conventional cytology, liquid based cytology, and four strategies with different age cut-off points and follow up times that used combined liquid based cytology and human papillomavirus testing (adjunctive human papillomavirus testing).

RESULTS

The model predicts that compared with using conventional cytology without testing for human papillomavirus, testing for the virus in conjunction with liquid based cytology for women with borderline or mildly dyskaryotic cervical smear results (aged 35 or more) would cost 3735 pounds sterling (5528 euros; 6474 dollars) per life year saved. Extending adjunctive human papillomavirus testing in combination with liquid based cytology to include women aged between 25 and 34 costs an additional 4233 pounds sterling per life year saved. Human papillomavirus testing is likely to reduce lifetime repeat smears by 52%-86% but increase lifetime colposcopies by 64%-138%.

CONCLUSIONS

Testing for human papillomavirus to manage all women with borderline or mildly dyskaryotic cervical smear results is likely to be cost effective. The predicted increase in lifetime colposcopies, however, deserves careful consideration.

Screening for Cervical Cancer in High-Risk Populations: DNA Pap Test or Hybrid Capture II Test Alone?

This study was designed to evaluate whether Hybrid Capture II (HC2) test alone refer women to colposcopy as appropriately as DNA Papanicolaou (Pap) test, in the context of a high-risk group of women using the recently validated DNACitoliq LBC system. Women with suspected cervical disease were included in this cross-sectional study at a tertiary center in São Paulo, Brazil, for further workup. All women had cervical material collected for LBC and HC2 for high-risk human papillomavirus (hrHPV)-DNA test. Irrespective of cytology and HC2 results, colposcopy, and cervical biopsy when applicable, was systematically performed. All tests were performed blindly. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of both methods were computed in relation to histology. A total of 1,080 women were included: 36.4% (393/1080) had ACUS+, 10.2% (110/1080) were high-grade squamous intraepithelial lesions (HSIL) or cancer. Mean age was 33.5 years. All women underwent colposcopy, and cervical biopsies were performed in 38.4% (415/1080): 33% (137/415) of the biopsies were negative, 14.4% (155/415) were low-grade squamous intraepithelial lesions (LSIL), 10.7% (116/415) were HSIL, and 0.6% (7/415) were cancer. HC2 sensitivity to diagnose biopsy-proven HSIL was 100%. Because all HSIL cases had a positive HC2 test, sensitivity could not be improved by adding LBC. Specificity and positive and negative predictive values of DNA Pap were not significantly different from HC2 test alone when considering LSIL+ histology as "gold standard" and HSIL+ histology. As a screening strategy for women with high-risk for cervical cancer, DNA Pap test does not seem to add substantially to HC2 alone in terms of appropriately referring to colposcopy.

The role of human papillomavirus testing in cervical screening

Organised, cytology-based cervical screening has led to a reduction in deaths associated with cervical cancer. Human papillomavirus (HPV) is necessary for the development of cervical cancer and associated pre-cursor cervical intraepithelial neoplasia and accumulated evidence suggests that incorporation of HPV testing could further refine screening programmes. HPV testing is discussed in the context of primary screening, for triage, and as a test of cure of treatment and possible value in developing countries. The high negative predictive value of a "double negative" cytology and HPV result could allow considerable changes in policy such as increased intervals between screening rounds, adjustment of age ranges for testing and schedule for return to routine screening post treatment. HPV testing for the triage of women to colposcopy with borderline or atypical squamous cells of undetermined significance (ASCUS) cytology could be clinically effective, but may be limited in women with low-grade squamous intraepithelial lesions (LSIL) or mild dyskaryosis by high HPV prevalence. Markers of HPV persistence harbour enormous potential to identify women at greatest risk of disease progression. Due to the diversity of existing cytology-based screening programmes, full cost-effectiveness analyses of HPV testing should be performed and assessed within local contexts.

Cost-effectiveness of human papillomavirus DNA testing in the United Kingdom, The Netherlands, France, and Italy

BACKGROUND

European countries with established cytology-based screening programs for cervical cancer will soon face decisions about whether to incorporate human papillomavirus (HPV) DNA testing and what strategies will be most cost-effective. We assessed the cost-effectiveness of incorporating HPV DNA testing into existing cervical cancer screening programs in the United Kingdom, The Netherlands, France, and Italy.

METHODS

We created a computer-based model of the natural history of cervical carcinogenesis for each using country-specific data on cervical cancer risk and compared each country's current screening policy with two new strategies: 1) cytology throughout a woman's lifetime, using HPV DNA testing as a triage strategy for equivocal cytology results ("HPV triage"), as well as 2) cytology until age 30 years and HPV DNA testing in combination with cytology in women more than 30 years of age ("combination testing"). Outcomes included reduction in lifetime cervical cancer risk, increase in life expectancy, lifetime costs, and incremental cost-effectiveness ratios, expressed as cost per year of life saved. We explored alternative protocols and conducted sensitivity analysis on key parameters of the model over a relevant range of values to identify the most cost-effective options for each country.

RESULTS

Both HPV DNA testing strategies, HPV triage and combination testing, were more effective than each country's status quo screening policy. Incremental cost-effectiveness ratios for HPV triage were less than $13,000 per year of life saved, whereas those for combination testing ranged from $9800 to $75,900 per year of life saved, depending on screening interval. We identified options that would be very cost-effective (i.e., cost-effectiveness ratio less than the gross domestic product per capita) in each of the four countries.

CONCLUSIONS

HPV DNA testing has the potential to improve health benefits at a reasonable cost compared with current screening policies in four European countries.

Genital infection with human papillomavirus in adolescents

Human papillomavirus (HPV) infection is one of the most common sexually transmitted infections in adolescents. Such infection is associated with substantial health risks and is unpredictable in its resolution. Genital warts are the most common clinical manifestations of genital HPV infections. Most genital warts are caused by low risk HPV types (notably HPV-6 and -11). The majority of genital HPV infections are latent or subclinical. Although the outcome of a genital HPV infection is variable, the infection is usually transient and complete resolution is common. However, persistent infections with high-risk HPV types (notably HPV-16 and -18) are associated with the development of cervical intraepithelial dysplasia (CIN), which may progress to cervical cancer. Genital warts, generally diagnosed in the clinic, can be treated with imiquimod, podofilox, podophyllin, liquid nitrogen, bichloroacetic or trichloroacetic acid, or surgery. Cervical cytology screening is an ideal screening test for subclinical HPV infection with resultant CIN. Annual cervical cytology screening should begin approximately 3 years after initiation of sexual intercourse but no later than age 21 years. Because of the high rate of regression of low-grade squamous intraepithelial lesions (LSIL) in adolescents, the cytologic study should be repeated within 6 to 12 months. Colposcopy should be reserved for persistent LSIL. Patients with high-grade squamous intraepithelial lesions (HSIL) should be referred for colposcopy and biopsy. Confirmed HSIL should be treated with cryotherapy, laser therapy, or loop electrosurgical excisional procedure. The use of therapeutic vaccines is still experimental. HPV infection can be prevented, to a certain extent, by delaying the initiation of sexual activity, limiting the number of sexual partners, and using latex condoms. Several viruslike particle candidate vaccines are under development for the prevention of HPV. These vaccines have been proven safe, well tolerated, highly immunogenic, and highly efficacious. Such vaccines are urgently needed and ultimately may be an important preventive measure.

The cost-effectiveness of human papillomavirus screening for cervical cancer. A review of recent modelling studies

We compared findings from recent studies modelling the cost-effectiveness of screening for cervical cancer using human papillomavirus (HPV) testing and alternative strategies. Data were standardized to facilitate comparison of costs per life year or costs per QALY gained in six studies. Absolute changes in costs, life years and QALYs for each strategy were normalized to a comparison with no screening. Costs were standardized to US$ in 2000 values. Most models assume screening starts at age 18 or 20 years. Assumed prevalence of HPV ranges from 10% for those aged 18 years to 20% for those aged 20-25 years and drops substantially after age 30. All except one model assume sensitivity to LSIL of 83% or higher. Two models distinguish the increasing specificity of HPV testing in older age groups (up to 95% for LSIL in women aged 55 years or older). All the models include consultation costs as well as screening and treatment costs, but costs for follow-up diagnosis and treatment vary considerably. Two models also include patient time costs. Despite these differences all strategies involving HPV testing have cost per quality-adjusted life-year (QALY) ratios in the range of USD 12,400-16,600. Costs per life year vary more widely, the highest being USD 19,246 (annual screening with liquid cytology and HPV). However, excluding strategies using liquid cytology, the highest costs per life year for a strategy including HPV testing are under USD 14,000 (simultaneous conventional cytology and HPV every two years). The cost per life year for HPV testing alone triennially is lower than for Pap smear testing alone biennially. Costs per QALY are generally lower than costs per life year (given the reported modelling assumptions and settings). Even with inclusion of patient costs, no strategies involving HPV testing cost more than USD 16,600 per QALY. Adoption of the ACOG guidelines to include HPV testing with cytology as a screening option for women aged 30 years or older therefore appears to be cost-effective.

Natural history and screening model for high-risk human papillomavirus infection, neoplasia and cervical cancer in the Netherlands

A simulation model is presented that assumes that persistent infection with high-risk human papillomavirus (hrHPV) is a necessary cause of cervical cancer. For the estimation of the model parameters, data of recent Dutch follow-up studies were reanalyzed. The predicted incidences of cervical cancer, cervical intraepithelial neoplasia (CIN1, CIN2 and CIN3) and abnormal cytology were validated with nationwide figures and population-based screening results. The model predicted a lifetime risk for cervical cancer of 2.9% with a peak at age 48 years. The predicted lifetime risk dropped to 0.4% when attending cervical screening. For women who were not hrHPV infected at 30 years, the lifetime risk was 1.6%. Sensitivity analyses were performed to check natural history assumptions that were only weakly identified from available data sets. The incidence of CIN3 observed with screening appeared a useful clinical end point as the predicted incidence was robust against changes in the sensitivity of cervical cytology and the duration to CIN3. The model can be used to study the health-economic benefits that can be achieved in nationwide screening when including an hrHPV test.