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

Comprehensive cancer control-research & development: knowing what we do and doing what we know

Comprehensive cancer control is defined as an integrated and coordinated approach to reducing cancer incidence, morbidity, and mortality across the cancer control continuum from primary prevention to end-of-life care. This approach assumes that when the public sector, non-governmental organizations, academia, and the private sector share with each other their skills, knowledge, and resources, a country can take advantage of all its talents and resources to more quickly reduce the burden of cancer for all its population. One critical issue for comprehensive cancer control is the extent to which the private sector can contribute to cancer prevention and control programs and policies that have historically been lead by the public health sector, and similarly how can the public sector increase its investment and involvement in clinical research and practice issues that are largely driven by the private sector worldwide?

In addition, building capacity to integrate research that is appropriate to the culture and context of the population will be important in different settings, in particular research related to cancer control interventions that have the capacity to influence outcomes. To whatever extent cancer control research is ultimately funded through the private and public sectors, if investments in research discoveries are ultimately to benefit the populations that bear the greatest burden of disease, then new approaches to integrating the lessons learned from science with the lessons learned from service (public health, clinical, and public policy) must be found to close the gap between what we know and what we do. Communities of practice for international cancer control, like the ones fostered by the first three International Cancer Control Congresses, represent an important forum for knowledge exchange opportunities to accelerate the translation of new knowledge into action to reduce the burden of cancer worldwide.

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.

Development of a quality framework for models of cervical screening and its application to evaluations of the cost-effectiveness of HPV vaccination in developed countries

BACKGROUND

HPV vaccination has now been introduced in most developed countries, but this has occurred in the context of established cervical cancer screening mechanisms which provide population-level protection against the most common HPV-related cancer. Therefore, estimating the cost-effectiveness of HPV vaccination to further reduce HPV-related disease depends in large part on the estimation of the effectiveness of the cervical screening 'background'. The aim of this study was to systematically review and assess methods for simulating cervical screening in decision analytic models used for evaluation of HPV vaccination.

METHODS

Existing quality frameworks for economic models were extended to develop a specific quality framework for models of cervical screening. This involved domains for model structure, parameterisation (data sources) and validation (consistency). A systematic review of economic evaluations of HPV vaccination was then conducted, and assessment of cervical screening model components was then performed via application of the new quality framework.

RESULTS

Generally, models took into account population-level cervical screening participation, but were inconsistent in their approach to modelling abnormal smear management, diagnostic evaluation and treatment of precancerous disease. There was also considerable variability in the accuracy of modelling clinical pathways and the scope of validation performed for screening-related outcomes, with focus directed towards cervical cancer targets. Only a few models comprehensively validated against observed pre-cancerous abnormalities.

CONCLUSION

Models of HPV vaccination in developed countries can be improved by further attention to the 'background' modelling of secondary protection via cervical screening. The quality framework developed for this review can be used to inform future HPV vaccination evaluations, including evaluations of the cost-effectiveness of male vaccination and next generation HPV vaccines, and to assess models used to evaluate new cervical screening technologies and recommendations.

Effectiveness of two strategies to follow-up ASC-US and LSIL screening results in The Netherlands using repeat cytology with or without additional hrHPV testing: a retrospective cohort study

PURPOSE

The purpose of the study was to assess the effectiveness of repeat cytology with and without additional high-risk human papilloma virus (hrHPV) testing after atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion (ASC-US/LSIL) screening results.

METHODS

In the Netherlands, ASC-US/LSIL is triaged by repeat cytology at 6 months or repeat cytology at 6 months with additional hrHPV testing. ASC-US/LSIL results from 13,734 screenees in 2008 were extracted from "Dutch Pathology Registry" including cytology, histology, and/or HPV follow-up results. Proportions of compliance, repeat cytology, referral, and detected cervical intraepithelial neoplasia (CIN) were assessed.

RESULTS

With additional hrHPV testing, 46.8 % was send back to regular screening at 6 months, 28.6 % needed second repeat cytology, and 24.6 % was referred for colposcopy. Without additional hrHPV testing, this was 0.0, 76.1, and 23.9 %, respectively. With additional hrHPV testing, significantly higher proportions of persisting ASC-US/LSIL; compliance with repeat/referral advices; and histological detection of CIN0 (no CIN or cancer), CIN1, and CIN2 were found but equal proportions CIN3+.

CONCLUSIONS

Additional hrHPV testing shortens follow-up without altering CIN3+ detection. Detection of CIN0, CIN1, and CIN2 was higher, presumably by hrHPV-driven biased cytology and detection bias. Restricting additional hrHPV testing to older women, reading cytology without knowledge of hrHPV status, and addition of more specific triage tests could further improve the effectiveness of additional hrHPV testing.

Triaging borderline/mild dyskaryotic Pap cytology with p16/Ki-67 dual-stained cytology testing: cross-sectional and longitudinal outcome study

Background:

Women with borderline/mildly dyskaryotic (BMD) cytology smears are currently followed up with repeat testing at 6 and 18 months. The objective of this study is to analyse the cross-sectional and longitudinal performance of p16/Ki-67 dual-stained cytology for the detection of cervical intraepithelial neoplasia (CIN) grade 3 or worse (CIN3+) and CIN2+ in women with BMD, and to compare the results with baseline human papillomavirus (HPV) testing.

Methods:

Conventional Pap cytology specimens of 256 women with BMD were dual stained for p16/Ki-67 retrospectively, and compared with baseline HPV results and long-term follow-up results.

Results:

p16/Ki-67 dual-stained cytology showed a sensitivity of 100%, a specificity of 64.4% and a negative predictive value (NPV) of 100.% for CIN3+. Human papillomavirus testing demonstrated similar sensitivity (96.3%), and NPV (99.1%), but a significantly lower specificity (57.6% P=0.024) for CIN3+. Sensitivity, specificity and NPV for CIN2+ of dual-stained cytology were 89.7%, 73.1% and 95.1%, respectively, which was similar when compared with HPV testing. Dual-stained cytology showed a significant lower referral rate than HPV testing (43.6% vs 49.1% P=0.043). During long-term follow-up, no CIN3+ lesions developed in HPV-positive, dual-stained negative women.

Conclusions:

Comparable sensitivity and NPV of dual-stained cytology for CIN3+, combined with a significantly higher specificity, makes p16/Ki-67 dual-stained cytology a viable alternative to HPV testing for triaging BMD.

Utility of P16 expression and Ki-67 proliferation index in ASCUS and ASC-H pap tests

Current cervical screening uses a combination of cytology and high-risk human papillomavirus (HR-HPV) analysis in cases of atypical squamous cells of undetermined significance (ASCUS) and atypical squamous cells cannot exclude high-grade intraepithelial lesion (ASC-H). These diagnoses are subject to interobserver variability and HR-HPV analysis can be limited by sampling inadequacy. This study correlates immunoexpression of P16 and Ki-67 in residual cervicovaginal material against cytology category and HR-HPV status. Eighteen pap tests were selected: 8 ASCUS, 4 ASC-H, and 6 controls (2 LSIL and 4 HSIL). Digene Hybrid Capture II test was used to detect HR-HPV. The cytospins were stained for P16/Ki-67. Pap tests, P16, Ki-67, HR-HPV result and available biopsies were correlated. P16 expression correlated with HR-HPV status in 15/17 cases. Discordant cases (1 ASCUS and 1 ASC-H) were +P16/-HR-HPV. Ki-67 correlated with HR-HPV in 8/15 cases. Discordant cases were +HR-HPV/- Ki-67 (HSIL, LSIL, and ASC-H one each), and -HR-HPV/+Ki-67 (3 ASCUS, 1 LSIL, 1 ASC-H). Two cases were + P16/+ Ki-67/- HR-HPV. None were - P16/- Ki-67/+ HR-HPV. Histologic follow-up in 13 cases varied from benign to CIN III. Two cases of +P16/ - Ki-67/- HR-HPV had benign cervical biopcies. Although a small sample size, our findings show a utility for adjunct P16/ Ki-67 in addition to HR-HPV testing in cases of squamous atypia when HR-HPVs are non-detected due to low DNA copies, or missed lesions in cervical biopsies.

Human papillomavirus testing versus repeat cytology for triage of minor cytological cervical lesions

BACKGROUND

Atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intra-epithelial lesions (LSIL) are minor lesions of the cervical epithelium, detectable by cytological examination of cells collected from the surface of the cervix of a woman.Usually, women with ASCUS and LSIL do not have cervical (pre-) cancer, however a substantial proportion of them do have underlying high-grade cervical intra-epithelial neoplasia (CIN, grade 2 or 3) and so are at increased risk for developing cervical cancer. Therefore, accurate triage of women with ASCUS or LSIL is required to identify those who need further management.This review evaluates two ways to triage women with ASCUS or LSIL: repeating the cytological test, and DNA testing for high-risk types of the human papillomavirus (hrHPV) - the main causal factor of cervical cancer.

OBJECTIVES

Main objective To compare the accuracy of hrHPV testing with the Hybrid Capture 2 (HC2) assay against that of repeat cytology for detection of underlying cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) or grade 3 or worse (CIN3+) in women with ASCUS or LSIL. For the HC2 assay, a positive result was defined as proposed by the manufacturer. For repeat cytology, different cut-offs were used to define positivity: Atypical squamous cells of undetermined significance or worse (ASCUS+), low-grade squamous intra-epithelial lesions or worse (LSIL+) or high-grade squamous intra-epithelial lesions or worse (HSIL+).Secondary objective To assess the accuracy of the HC2 assay to detect CIN2+ or CIN3+ in women with ASCUS or LSIL in a larger group of reports of studies that applied hrHPV testing and the reference standard (coloscopy and biopsy), irrespective whether or not repeat cytology was done.

SEARCH METHODS

We made a comprehensive literature search that included the Cochrane Register of Diagnostic Test Accuracy Studies; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (through PubMed), and EMBASE (last search 6 January 2011). Selected journals likely to contain relevant papers were handsearched from 1992 to 2010 (December). We also searched CERVIX, the bibliographic database of the Unit of Cancer Epidemiology at the Scientific Institute of Public Health (Brussels, Belgium) which contains more than 20,000 references on cervical cancer.More recent searches, up to December 2012, targeted reports on the accuracy of triage of ASCUS or LSIL with other HPV DNA assays, or HPV RNA assays and other molecular markers. These searches will be used for new Cochrane reviews as well as for updates of the current review.

SELECTION CRITERIA

Studies eligible for inclusion in the review had to include: women presenting with a cervical cytology result of ASCUS or LSIL, who had undergone both HC2 testing and repeat cytology, or HC2 testing alone, and were subsequently subjected to reference standard verification with colposcopy and colposcopy-directed biopsies for histologic verification.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data from the selected studies, and obtained additional data from report authors.Two groups of meta-analyses were performed: group I concerned triage of women with ASCUS, group II concerned women with LSIL. The bivariate model (METADAS-macro in SAS) was used to assess the absolute accuracy of the triage tests in both groups as well as the differences in accuracy between the triage tests.

MAIN RESULTS

The pooled sensitivity of HC2 was significantly higher than that of repeat cytology at cut-off ASCUS+ to detect CIN2+ in both triage of ASCUS and LSIL (relative sensitivity of 1.27 (95% CI 1.16 to 1.39; P value < 0.0001) and 1.23 (95% CI 1.06 to 1.4; P value 0.007), respectively. In ASCUS triage, the pooled specificity of the triage methods did not differ significantly from each other (relative specificity: 0.99 (95% CI 0.97 to 1.03; P value 0.98)). However, the specificity of HC2 was substantially, and significantly, lower than that of repeat cytology in the triage of LSIL (relative specificity: 0.66 (95% CI 0.58 to 0.75) P value < 0.0001).

AUTHORS' CONCLUSIONS

HPV-triage with HC2 can be recommended to triage women with ASCUS because it has higher accuracy (significantly higher sensitivity, and similar specificity) than repeat cytology. When triaging women with LSIL, an HC2 test yields a significantly higher sensitivity, but a significantly lower specificity, compared to a repeat cytology. Therefore, practice recommendations for management of women with LSIL should be balanced, taking local circumstances into account.

Cervical cancer prevention in HIV-infected women using the "see and treat" approach in Botswana

BACKGROUND

Cervical cancer is a major public health problem in resource-limited settings, particularly among HIV-infected women. Given the challenges of cytology-based approaches, the efficiency of new screening programs need to be assessed.

SETTING

Community and hospital-based clinics in Gaborone, Botswana.

OBJECTIVE

To determine the feasibility and efficiency of the "see and treat" approach using visual inspection acetic acid (VIA) and enhanced digital imaging (EDI) for cervical cancer prevention in HIV-infected women.

METHODS

A 2-tier community-based cervical cancer prevention program was implemented. HIV-infected women were screened by nurses at the community using the VIA/EDI approach. Low-grade lesions were treated with cryotherapy on the same visit. Women with complex lesions were referred to our second tier specialized clinic for evaluation. Weekly quality control assessments were performed by a specialist in collaboration with the nurses on all pictures taken.

RESULTS

From March 2009 through January 2011, 2175 patients were screened for cervical cancer at our community-based clinic. Two hundred fifty-three patients (11.6%) were found to have low-grade lesions and received same-day cryotherapy. One thousand three hundred forty-seven (61.9%) women were considered to have a normal examination, and 575 (27.3%) were referred for further evaluation and treatment. Of the 1347 women initially considered to have normal exams, 267 (19.8%) were recalled based on weekly quality control assessments. Two hundred ten (78.6%) of the 267 recalled women, and 499 (86.8%) of the 575 referred women were seen at the referral clinic. Of these 709 women, 506 (71.4%) required additional treatment. Overall, 264 cervical intraepithelial neoplasia stage 2 or 3 were identified and treated, and 6 microinvasive cancers identified were referred for further management.

CONCLUSIONS

Our "see and treat" cervical cancer prevention program using the VIA/EDI approach is a feasible, high-output and high-efficiency program, worthy of considering as an additional cervical cancer screening method in Botswana, especially for women with limited access to the current cytology-based screening services.

Cytology and human papillomavirus testing 6 to 12 months after ASCUS or LSIL cytology in organized screening to predict high-grade cervical neoplasia between screening rounds

We carried out a prospective study comparing the performance of human papillomavirus (HPV) E6/E7 mRNA (PreTect HPV-Proofer; NorChip, Klokkarstua, Norway) and DNA (Amplicor HPV test; Roche Diagnostics, Basel, Switzerland) triage testing of women 6 to 12 months after atypical-squamous-cells-of-undetermined-significance (ASCUS) or low-grade-squamous-intraepithelial-lesion (LSIL) cytology in organized screening to predict high-grade cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) between screening rounds. Between January 2005 and April 2008, 692 study women with screening-detected ASCUS/LSIL cytology 6 to 12 months earlier returned for HPV mRNA and DNA testing and repeat cytology. The median follow-up time was 3 years, using existing health care facilities. Follow-up test results were available for 625 women. Of the 145 CIN2+ cases detected during the study period, 95 (65.5%) were HPV mRNA positive 6 to 12 months after screening-detected ASCUS/LSIL, 44 (30.4%) were HPV mRNA negative, and 6 (4.1%) were invalid. The corresponding HPV DNA results were 139 (95.9%), 5 (3.4%), and 1 (0.7%), respectively. The cumulative incidences of CIN2+ 3 years after a negative HPV mRNA and DNA test were 10.3% (95% confidence interval [CI], 7.2 to 13.3%) and 1.8% (95% CI, 0.0 to 3.6%), respectively. The cumulative incidences of CIN2+ 3 years after positive HPV mRNA and DNA tests were 52.8% (95% CI, 40.1 to 60.1%) and 41.3% (95% CI, 35.5 to 46.6%), respectively. In conclusion, both positive HPV mRNA and DNA test results have a high enough long-term prediction of CIN2+ risk to consider referral to colposcopy as good practice when performed in delayed triage of women with ASCUS/LSIL cytology. In addition, the low CIN2+ risk among women with a negative Amplicor HPV test in our study confirms its safe use in a clinical setting.

Long-term CIN3+ risk in women with abnormal cytology; role of hrHPV testing

Background:

Many studies have examined the short-term value of high-risk human papillomavirus (hrHPV) testing in predicting cumulative risk of cervical intraepithelial neoplasia grade 3 or cancer (CIN3+). This study focuses on long-term CIN3+ risk after initial wait and see policy.

Methods:

A total of 342 women with abnormal cytology of borderline/mild dyskaryosis (BMD) or worse (>BMD), included between 1990 and 1992, were followed-up by cytology and hrHPV testing until 1996 and monitored by cytology thereafter. Primary endpoint was cumulative CIN3+ risk by December 2009.

Results:

Women with BMD had a 5-year CIN3+ risk of 22.5% (95% confidence interval (CI) 17.0–29.1) and of 0.7% (0.1–4.5) in the subsequent 5 years. High-risk human papillomavirus-negative women with BMD had a 5-year risk of <0.01% (95% CI 0.0–5.1) and of <0.01% (0.0–5.7) in the following 5 years, while for hrHPV-positive women these risks were 37.5% (29.0–46.9) and 1.6% (0.2–9.5), respectively. Women with >BMD had a 5-year risk of 45.1% (36.4–54.1) and of 3.5% (0.9–12.2) in the subsequent 5 years. High-risk human papillomavirus-negative women with >BMD had a 5-year risk of 7.3% (2.0–23.6) and hrHPV-positive women of 56.6% (46.4–66.3).

Conclusion:

Women with BMD have an elevated CIN3+ risk for 5 years only; afterwards their risk is similar to the general population. High-risk human papillomavirus-negative women with BMD may return to regular screening directly. All other women with ⩾BMD should be referred for additional testing and/or colposcopy.

Economic evaluation of three populational screening strategies for cervical cancer in the county of Valles Occidental: CRICERVA clinical trial

Background

A high percentage of cervical cancer cases have not undergone cytological tests within 10 years prior to diagnosis. Different population interventions could improve coverage in the public system, although costs will also increase. The aim of this study was to compare the effectiveness and the costs of three types of population interventions to increase the number of female participants in the screening programmes for cancer of the cervix carried out by Primary Care in four basic health care areas.

Methods/Design

A cost-effectiveness analysis will be performed from the perspective of public health system including women from 30 to 70 years of age (n = 20,994) with incorrect screening criteria from four basic health care areas in the Valles Occidental, Barcelona, Spain. The patients will be randomly distributed into the control group and the three intervention groups (IG1: invitation letter to participate in the screening; IG2: invitation letter and informative leaflet; IG3: invitation letter, informative leaflet and a phone call reminder) and followed for three years. Clinical effectiveness will be measured by the number of HPV, epithelial lesions and cancer of cervix cases detected. The number of deaths avoided will be secondary measures of effectiveness. The temporal horizon of the analysis will be the life expectancy of the female population in the study. Costs and effectiveness will be discounted at 3%. In addition, univariate and multivariate sensitivity analysis will be carried out.

Discussion

IG3 is expected to be more cost-effective intervention than IG1 and IG2, with greater detection of HPV infections, epithelial lesions and cancer than other strategies, albeit at a greater cost.

Trial Registration

Clinical Trials.gov Identifier NCT01373723

Calibrating models in economic evaluation: a seven-step approach

In economic evaluation, mathematical models have a central role as a way of integrating all the relevant information about a disease and health interventions, in order to estimate costs and consequences over an extended time horizon. Models are based on scientific knowledge of disease (which is likely to change over time), simplifying assumptions and input parameters with different levels of uncertainty; therefore, it is sensible to explore the consistency of model predictions with observational data. Calibration is a useful tool for estimating uncertain parameters, as well as more accurately defining model uncertainty (particularly with respect to the representation of correlations between parameters). Calibration involves the comparison of model outputs (e.g. disease prevalence rates) with empirical data, leading to the identification of model parameter values that achieve a good fit. This article provides guidance on the theoretical underpinnings of different calibration methods. The calibration process is divided into seven steps and different potential methods at each step are discussed, focusing on the particular features of disease models in economic evaluation. The seven steps are (i) Which parameters should be varied in the calibration process? (ii) Which calibration targets should be used? (iii) What measure of goodness of fit should be used? (iv) What parameter search strategy should be used? (v) What determines acceptable goodness-of-fit parameter sets (convergence criteria)? (vi) What determines the termination of the calibration process (stopping rule)? (vii) How should the model calibration results and economic parameters be integrated? The lack of standards in calibrating disease models in economic evaluation can undermine the credibility of calibration methods. In order to avoid the scepticism regarding calibration, we ought to unify the way we approach the problems and report the methods used, and continue to investigate different methods.

Economic evaluation of strategies for managing women with equivocal cytological results in Brazil

In Brazil, current management of women with screening results of atypical squamous cells of undetermined significance (ASC-US) is to offer repeat testing at 6-month intervals. Alternative management strategies that have been adopted in many high-income settings are to offer immediate colposcopy referral or to utilise human papillomavirus (HPV) DNA testing as a triage for colposcopy referral, and to consider different strategies according to women's age. The objective of our study was to evaluate the lifetime cost effectiveness in terms of cost per years of life saved (YLS) of these alternative strategies for a middle income setting. A Markov model was developed using data from the Ludwig-McGill cohort and calibrated to independent observational datasets and local cost estimates obtained. In the base-case analysis, repeat cytology was the least costly strategy but also the least effective. Based on the WHO threshold for very cost-effective interventions, HPV triage for women above 30 years-old was the strategy with the highest probability of being cost effective. HPV triage including younger women with ASCUS results would also be a cost-effective option. Whilst there was a slight further gain in effectiveness with immediate colposcopy referral, it was also more expensive and did not appear to be cost effective. Threshold analysis indicated that an HPV test would have to be more than twice as expensive as a cytology test for HPV triage to no longer be cost effective. In conclusion, our results indicate that in middle income settings HPV triage is likely to be the optimal strategy for managing women presenting with ASC-US results.

The role of human papillomavirus testing in the management of women with low-grade abnormalities: multicentre randomised controlled trial

OBJECTIVE

To assess the value of a single human papillomavirus (HPV) test in making decisions on management of women with cervical cytology showing borderline nuclear abnormality (BNA) or mild dyskaryosis. In particular, to determine whether information on high-risk (hr) HPV status would be valuable in the choice between (1) cytological surveillance versus immediate referral to colposcopy, and (2) at colposcopy, between biopsy and recall versus immediate large loop excision of the transformation zone (LLETZ).

DESIGN

Multicentre individually randomised controlled trial, nested within the NHS Cervical Screening Programmes, investigating the value of HPV testing by testing for interactions between HPV status and (1) cytological surveillance versus colposcopy, and (2) biopsy and recall versus immediate LLETZ. Setting Grampian, Tayside and Nottingham. Population Women (n = 4439), aged 20-59 years, with a cytology test showing borderline nuclear abnormalities or mild dyskaryosis during October 1999 to October 2002.

METHODS

High-risk HPV status was determined at recruitment using the polymerase chain reaction assay with the GP5+/6+ general primer system. The results of this HPV testing were not disclosed to either the participating women or to those involved in their management. Women were randomised to either (1) 6-monthly cytological screening in primary care or (2) referral for colposcopy. Human papillomavirus status was used to stratify both randomisations. All women were followed for 3 years, concluding with an invitation to an exit appointment at which colposcopic examination was undertaken. In addition, in women who were randomised to initial colposcopy and underwent colposcopy, the association between hrHPV status and presence of cervical intraepithelial neoplasia (CIN) grade 2 or more severe disease (henceforth CIN2 or worse) was examined.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values of the HPV test for predicting CIN2 or worse and the implications for the choice of management between cytological surveillance and immediate referral for colposcopy.

RESULTS

There were no significant interactions between management and HPV status. Hence, in women with mild dyskaryosis or BNA who are HPV positive, there is no advantage of (1) immediate colposcopy over cytological surveillance (P = 0.76) or (2) immediate LLETZ over biopsy and recall (P = 0.27). The sensitivity of HPV testing for detection of CIN2 or worse was 75.2% (95% CI 68.8-81.0%) among women with mild dyskaryosis and 69.9% (95% CI 61.7-77.3%) among those with BNA. Specificity was higher in those with BNA (71.3%; 95% CI 68.5-74.1%) than in those with mild dyskaryosis (46.9%; 95% CI 42.2-51.6%). Sensitivity decreased with increasing age whereas specificity increased. The negative predictive value was high, particularly among women with BNA (94.5%; 95% CI 92.9-96.0%). Across all ages, 22% of women who had CIN2 or worse were HPV negative. Conversely, 40% of those who were HPV positive did not have CIN. HPV was a much more reliable predictor in women aged over 40 years.

CONCLUSIONS

We conclude that in younger women with low-grade cytological abnormalities, a single HPV test would not be useful in determining who should be referred for colposcopy or the most effective management at colposcopy. In women over 40, a negative HPV test could be used to rule out further investigation.

Evaluation of the performance of the novel PapilloCheck HPV genotyping test by comparison with two other genotyping systems and the HC2 test

The novel PapilloCheck genotyping test was compared with SPF10 PCR LiPav1 and PGMY09/11 on hybrid capture 2 (HC2)-pretested samples. From results of 826 cervical samples detection rates and kappa values for the tests were calculated using a HPV type consensus definition. With PapilloCheck HPV types 53, 56, and 33 were found with a sensitivity of 100%. The lowest detection rate was observed for HPV 35 (72.2%). The SPF10 PCR LiPav1 was found to be 100% positive for HPV 18, 31, 53, 56, and 35 and lowest for HPV 59 (81%). The PGMY09/11 system detected only HPV 59 at 100% detection rate and showed lowest sensitivity for HPV 56 (40.5%). Multiple infection rates ranged from 25.8% (PGMY09/11 PCR-LBA), over 39.5% (PapilloCheck) to 55.9% (SPF10 PCR LiPav1). In samples with higher viral DNA load detection rates and concordance between the genotyping tests increases. The kappa values in comparison to the HPV consensus type ranged from k = 0.21 to k = 0.82 for comparing SPF10 PCR with the HPV consensus type, while values for PGMY09/11 PCR ranged from k = 0 to k = 0.96 and were best for the PapilloCheck (k = 0.49-0.98). Detection rates for the identification of high-grade cervical intraepithelial neoplasia (CIN2+) ranged from 93.7% (PGMY09/11 PCR) to 98.4% (PapilloCheck, SPF10 PCR, HC2). In conclusion, this study shows that the PapilloCheck give comparable results to established PCR methods. However, these results also show a necessity for the standardization of genotype-specific HPV detection assays.

Comparison of HPV and cytology triage algorithms for women with borderline or mild dyskaryosis in population-based cervical screening (VUSA-screen study)

We studied the effectiveness of high-risk human papillomavirus (hrHPV) triage for immediate colposcopy in women with borderline or mild dyskaryosis (BMD). In the Utrecht province of the Netherlands, women aged 30-60 years who participated in the regular cervical screening programme were offered hrHPV testing and cytology (intervention group) or cytology only (control group). In the intervention group (n = 337), women with BMD were immediately referred for colposcopy only if the sample was hrHPV positive. Women with a hrHPV negative test were advised to repeat cytology at 6 and 18 months and were referred for colposcopy if and when the repeat test result was positive (BMD or worse). In the control group (n = 329), referral of women with BMD was delayed until cytology was repeatedly positive at 6 or 18 months. The CIN3 detection rates were 10.7% (36/337) in the intervention group and 6.4% (21/329) in the control group (p = 0.047). Moreover, hrHPV triaging resulted in shorter time to diagnosis (154 vs. 381 days). Although the number of colposcopy referrals was 51.5% higher in the intervention group than in the control group, the medical costs per detected CIN3 were slightly lower ([euro] 4781 vs. [euro] 6235). If, in addition, hrHPV negative women had been referred back to routine screening at baseline, the CIN3 rate would have been 10.1% (34/337) and colposcopy rate would only have been 30.4% higher than in the control group. This study shows that hrHPV triaging of women with BMD is at least as effective for detecting CIN3 as repeat cytology, also when hrHPV negative women are referred back to routine screening.

Comparison of the clinical performance of PapilloCheck human papillomavirus detection with that of the GP5+/6+-PCR-enzyme immunoassay in population-based cervical screening

We compared the clinical performance of the PapilloCheck human papillomavirus (HPV) assay with that of the GP5+/6+-PCR method with an enzyme immunoassay readout (GP5+/6+-PCR-EIA) for the detection of high-risk HPV (hrHPV) types by the use of cervical samples originating from women in a population-based by the use of cervical screening cohort tested by combined cytology and GP5+/6+-PCR-EIA (POBASCAM trial). Specimens from a random sample of 1,437 controls (women ages 40 to 60 years with normal cytological findings and without evidence of cervical intraepithelial neoplasia grade 2 or higher [> or = CIN2] within up to 8 years of follow-up) and 192 cases (women ages 30 to 60 years in whom > or = CIN3 was detected within up to 3 years of follow-up) were subjected to analysis by the PapilloCheck method. When all 17 (probably) hrHPV types were taken into account, the PapilloCheck assay had a clinical sensitivity for the detection of > or = CIN3 of 96.4% (185/192 samples; 95% confidence interval [CI], 93.7 to 99.7) and a clinical specificity for the detection of > or = CIN2 of 96.3% (95% CI, 95.3 to 97.3). After restriction of the analysis by the PapilloCheck assay to the 14 hr HPV types targeted by GP5+/6+-PCR-EIA, the clinical sensitivity and clinical specificity values were 95.8% (95% CI, 92.8 to 98.8) and 96.7% (95% CI, 95.7 to 97.7), respectively. By comparison, these values were 96.4% (95% CI, 93.9 to 98.9) and 97.7% (95% CI, 96.9 to 98.5), respectively, for the GP5+/6+-PCR-EIA. When all 17 (probably) hrHPV types were included in the analysis, noninferiority score testing revealed that the clinical sensitivity of the PapilloCheck assay for the detection of > or = CIN3 was noninferior to that of the GP5+/6+-PCR-EIA (P < 0.0001), but the clinical specificity of the PapilloCheck assay for the detection of > or = CIN2 was inferior to that of the GP5+/6+-PCR-EIA (P = 0.08) when lower bounds of 90% for sensitivity and 98% for specificity were used. When the analysis was restricted to the 14 hrHPV types targeted by the GP5+/6+-PCR-EIA, both the clinical sensitivity and the clinical specificity of the PapilloCheck assay were noninferior to those of the GP5+/6+-PCR-EIA (noninferiority score test; P < 0.0001 and P = 0.007, respectively). Thus, when the findings obtained for the 14 hrHPV types detectable by the GP5+/6+-PCR-EIA are considered, the PapilloCheck assay is clinically compatible with the GP5+/6+-PCR-EIA.

Triage of women with equivocal or low-grade cervical cytology results: a meta-analysis of the HPV test positivity rate

Consistent evidence underlines the utility of human papillomavirus (HPV) DNA testing in the management of women with equivocal cervical cytological abnormalities, but not in case of low-grade lesions. We performed a meta-analysis including studies where the high-risk probe of the Hybrid Capture-II is used to triage these two cytological categories. The triage test-positivity rate reflects the colposcopy referral workload.Data were pooled on the HPV test positivity rate in women with atypical squamous cells of undetermined significance (ASCUS/ASC-US) or low-grade squamous intraepithelial lesions (LSIL), derived from different cytological classification systems. The meta-analysis was restricted to studies, published between 1991 and 2007. A random-effect model was applied for meta-analytical pooling and the influence of covariates on the HPV positivity rate was analyzed by meta-regression. The variation by age was assessed within individual studies since age strata were not defined uniformly. On an average, 43% (95% CI: 40–46%) of women with ASCUS/ASC-US were high-risk HPV positive (range 23–74%). In women with LSIL, the pooled positivity rate was 76% (95% CI: 71–81%; range 55–89%). In spite of considerable inter-study heterogeneity, the difference in HPV positivity between the two triage groups was large and highly significant: 32% (95% CI: 27–38%). HPV rates dropped tremendously as age and cutoffs of test positivity increased. Other factors (cytological classification system, country, continent, collection method and year of publication) had no statistically significant impact, except in LSIL triage where HPV positivity was significantly lower in European compared to American studies. Women with LSIL, especially younger women, have high HPV positivity rates suggesting limited utility of reflex HPV triaging these cases. Research is needed to identify more specific methods to triage women with low-grade squamous cervical lesions.

High-risk human papillomavirus DNA load in a population-based cervical screening cohort in relation to the detection of high-grade cervical intraepithelial neoplasia and cervical cancer

In a population-based cervical screening cohort, we determined the value of type-specific viral load assessment for the detection of high-grade cervical intraepithelial neoplasia and cervical cancer (>or=CIN2). Viral load was determined by type-specific real-time PCR in women with single HPV16,-18,-31 and -33 infections, as determined by GP5+/6+-PCR. Study endpoints were the detection of cumulative >or=CIN2 or>or=CIN3 within 18 months of follow-up. High viral loads of HPV16,-31, and -33 were predictive for >or=CIN2 (relative risk of 1.6 (95% CI: 1.3-1.9), 1.7 (95% CI: 1.1-2.7) and 1.9 (95% CI: 1.1-3.1) per 10-fold change in viral load, respectively). For HPV18, the relative risk was of similar magnitude (1.5, 95% CI: 0.7-3.1), though not significant (p=0.3). Subsequently, we determined the sensitivities of viral load for >or=CIN2 and >or=CIN3 in HPV DNA-positive women using viral load thresholds previously defined in a cross-sectional study. These thresholds were based on the 25th, 33rd and 50th percentiles of type-specific HPV16,-18,-31 or -33 viral load values found in women with normal cytology. For all types, combined sensitivities for >or=CIN2 were 93.5%, 88.8% and 77.7% for the 25th, 33rd and 50th percentile thresholds, respectively. Response-operator-characteristics (ROC) curve analysis showed that viral load testing on HPV DNA-positive women in addition to or instead of cytology may result in an increased sensitivity for >or=CIN2, but at the cost of a marked decrease in specificity in relation to cytology. Similar results were obtained when using >or=CIN3 as endpoint. In conclusion, in a cervical screening setting viral load assessment of HPV16, 18, 31 and 33 has no additive value to stratify high-risk HPV GP5+/6+-PCR-positive women for risk of >or=CIN2 or>or=CIN3.

HPV16/18 vaccination to prevent cervical cancer in The Netherlands: model-based cost-effectiveness

We evaluated the cost-effectiveness of HPV16/18 vaccination for girls aged 12 years in The Netherlands in addition to cervical cancer screening. For this purpose, we developed a simulation model that describes the relation between each of the high-risk human papillomavirus (hrHPV) types and cervical disease, allowing the occurrence of multiple type-specific infections. Model parameters were derived from Dutch cohort studies, including a large population-based screening trial, and from the national cervical cancer registry. The model satisfactorily reproduced Dutch data on HPV infection and the presence of cervical lesions. For our base-case scenario in which 85% of the girls aged 12 years were vaccinated against types 16/18 (95% efficacy, lifelong protection), the model predicted a decrease of 60% in the number of cervical cancer cases and cervical cancer deaths indicating that substantial health benefits can be achieved. Health savings were robust against changes in the vaccine efficacy (varied from 85% to 98%) but savings showed a substantial reduction when the efficacy started waning 10 years after vaccination. The discounted costs per quality-adjusted life year (QALY) were euro 19,500/QALY (range euro 11,000 to euro 25,000/QALY) and lied near the cost-effectiveness threshold of euro 20,000/QALY used in The Netherlands. The simulations further showed that vaccination cannot replace screening because vaccination without screening was less effective than screening in preventing cancer in women over 40 years of age. In conclusion, our model results support the implementation of HPV16/18 vaccination in young women in addition to cervical cancer screening.

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.

Comparison of GP5+/6+-PCR and SPF10-line blot assays for detection of high-risk human papillomavirus in samples from women with normal cytology results who develop grade 3 cervical intraepithelial neoplasia

Using a case control approach, we performed a two-way comparison study between GP5+/6+-PCR and HPV SPF(10)-Line Blot 25 (SPF(10)) assays for detection of 14 types of high-risk human papillomavirus (hrHPV) in samples from women with normal cytology results who had or developed grade 3 cervical intraepithelial neoplasia (CIN 3). Samples were pooled from two cohorts, i.e., women participating in population-based screening and women attending a gynecological outpatient clinic. Cases (n = 45) were women with histologically confirmed CIN 3 diagnosed within a median follow-up time of 2.7 (range, 0.2 to 7.9) years. Control samples were from women (n = 264) who had developed CIN 1 lesions at maximum (median follow-up at 5.8 [range, 0 to 10] years). Identical numbers of cases tested positive for 1 or more of the 14 hrHPV types by both systems (40/45; McNemar; P = 1.0). Conversely, SPF(10) scored significantly more controls as hrHPV positive than did GP5+/6+-PCR (95/264 versus 29/264; McNemar; P < 0.001). Consequently, women with normal cytology results and an hrHPV GP5+/6+-PCR-positive test exhibited a risk of CIN 3 that was 4.5 times higher (odds ratio [OR], 65; 95% confidence interval [95%CI], 24 to 178) than that seen for women with an hrHPV-positive SPF(10) test (OR, 14; 95%CI, 5 to 38)). Similar results were obtained after analysis of both cohorts separately. Discrepancy analysis by viral load assessment for the most common discordant hrHPV types (HPV16, -18, and -52) showed that samples which were SPF(10) positive only for these types had viral loads significantly lower than those for samples that were positive by both assays (analysis of variance; P < or = 0.006). Our data indicate that GP5+/6+-PCR has a better clinical performance than SPF(10) for women who are diagnosed with CIN 3 after prior normal cytology results. The extra positivity scored by SPF(10) mainly involved infections characterized by low viral loads that do not result in CIN 3.

Comparison of molecular assays for detection and typing of human papillomavirus

OBJECTIVE

The objective of the study was to compare the performance of 3 different extraction instruments in conjunction with 4 different amplification and detection kits for detection and typing of human papillomavirus (HPV) deoxyribonucleic acid (DNA).

STUDY DESIGN

A total of 42 cervical swabs were investigated. HPV DNA was extracted on the 3 different instruments. Each of the extracts was then amplified, and HPV DNA amplification products were detected with 4 different kits.

RESULTS

In 31 samples, HPV DNA was detected by both the Amplicor HPV test and the LINEAR ARRAY HPV genotyping test in conjunction with DNA extraction on the easyMAG instrument. In another 6 samples, only low-risk types were detected with the linear array HPV genotyping test. After extraction on the easyMAG instrument, 32 samples tested positive when the PapilloCheck with the HotStarTaq DNA polymerase was used.

CONCLUSION

Together with extraction on the easyMAG instrument, the Amplicor HPV test, the linear array HPV genotyping test, and the new PapilloCheck with the HotStarTaq DNA polymerase provide comparable results allowing reliable and safe HPV diagnostics in the routine laboratory. Use of alternative assays may lead to an increase of invalid and divergent HPV typing results.

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.

A randomized trial of basing treatment on human papillomavirus and/or cytology results in low-grade cervical lesion triage

OBJECTIVE

This study was undertaken to compare management algorithms that base treatment with loop electrosurgical excision procedure on human papillomavirus and/or repeat Papanicolaou test smear results.

STUDY DESIGN

A randomized trial that referred 674 women with either atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesions cytology results, detected in organized screening to treatment either (1) if they were positive in a repeat Papanicolaou test smear and/or a human papillomavirus test or (2) if they were positive in the repeat Papanicolaou test smear test only. Women who tested positive were treated, regardless of colposcopic findings.

RESULTS

There were 208 of 337 (62%) women who were treated in the human papillomavirus /Papanicolaou test smear group (187/337 because of HPV positivity) and 138 of 337 (41%) in the Papanicolaou test smear only group. Histopathologically diagnosed cervical intraepithelial neoplasia grade 2 or worse was found among 112 of 337 (33.2%) women in the human papillomavirus/Papanicolaou test smear group compared with 85 of 337 (25.2%) women in the Papanicolaou test smear only group (P < .05). Twenty-one women with cervical intraepithelial neoplasia 2+ had normal colposcopy.

CONCLUSION

For adequate cervical intraepithelial neoplasia 2+ sensitivity, the decision to use loop electrosurgical excision procedure needs to be based on human papillomavirus testing results and should not exclude women with normal colposcopy.

Human papillomavirus triage of women with persistent borderline or mildly dyskaryotic smears: Comparison of costs and side effects of three alternative strategies

The conventional direct referral to colposcopy of persistent borderline or mildly dyskaryotic (BMD) smears in cervical cancer screening leads to considerable unnecessary referrals and associated anxiety and costs. This may be improved by including testing for oncogenic human papillomavirus (HPV) in the triage. We assessed costs and side effects (referrals, treatments and time in follow-up) for 3 possible HPV triage strategies (immediate HPV testing, a 6-month delay in HPV testing, a 2-stage combination of both) and compared them with the conventional strategy. The assessments are based on recent Dutch data from various national databases and trials. We estimated that the referral rate could be reduced by 49, 58 and 58% with immediate, delayed and 2-stage HPV testing, respectively. As a consequence, the average length of follow-up, as well as average costs, also decrease. Therefore, we advocate including HPV testing before referring to colposcopy. Among the 3 HPV strategies, analysis of additional aspects favors implementation of immediate HPV testing.

Assessing the introduction of universal human papillomavirus vaccination for preadolescent girls in The Netherlands

A persistent infection with human papillomavirus (HPV) is a prerequisite for the development of cervical cancer. Clinical trials with HPV-vaccines have been very successful in preventing persistent HPV16/18 infections, the two most oncogenic HPV-genotypes. We assessed the introduction of universal HPV-vaccination for preadolescent girls in the Dutch National Immunization Programme. Long-term vaccine efficacy, the need and extent of a catch-up programme for young women, and the impact of vaccination on the cervical cancer screening programme are major unresolved issues. Preliminary conservative estimates (80% vaccine efficacy and no effects on the screening programme, transmission rate, non-cervical cancer incidence, and cross protection) predict an acceptable cost-effectiveness ratio for universal vaccination of preadolescent girls.

Cost-effectiveness of human papillomavirus testing after treatment for cervical intraepithelial neoplasia

OBJECTIVE

To compare current cytological follow up of women treated for high-grade cervical intraepithelial neoplasia (CIN) with follow up by high-risk human papillomavirus (HPV) testing together with cytology.

DESIGN

A cost-effectiveness modelling study.

SETTING

Gynaecology clinics in the Netherlands.

POPULATION

Women treated for high-grade CIN.

METHODS

A Markov model was developed to compare six follow-up strategies with HPV testing with current cytological follow up at 6, 12, and 24 months. Model parameter estimation was based on three Dutch follow-up studies and a Dutch population-based screening cohort.

MAIN OUTCOME MEASURES

The number of CIN2/3 cases missed after 5 years follow up, the number of diagnostic procedures, and costs involved.

RESULTS

Strategies with adjunct HPV testing were more effective than current follow up (reduction in missed CIN2/3 cases 32-77%, corresponding to a number needed to treat of 192-455) and less inconvenient (reduction in repeat smears 28-65%). A particularly attractive strategy was HPV testing alone at 6 months and both HPV and cytological testing at 24 months after treatment. This strategy yielded a high detection rate of post-treatment CIN, did not lead to an increase in colposcopy rate, and was 49 Euro per woman cheaper than the current strategy.

CONCLUSIONS

Our model supports the use of high-risk HPV testing for monitoring women treated for high-grade CIN.

Referral compliance, outcome and predictors of CIN after repeated borderline cervical smears in the Netherlands

BACKGROUND

Borderline cytological abnormalities are diagnosed very frequently but have limited predictive value for high-grade cervical lesions, resulting in high costs, patient anxiety and over treatment. A conservative management strategy for the Dutch diagnostic equivalent of borderline nuclear changes (BNC) was introduced in the Netherlands in 1996, with repeat cytology at 6 and 18 months and referral for colposcopy if BNC is persistent.

OBJECTIVE

To analyse compliance with the current guidelines for referral, as well as the outcome after repeated BNC. Concurrently we investigated whether other variables are predictive of high-grade lesions.

METHODS

We retrieved 1898 eligible cases of repeated BNC with 4 years follow-up from the national pathology database (PALGA) and performed a nationwide survey.

RESULTS

The management strategy for women with repeated BNC in the Netherlands has been accepted and supported. Seventy-seven per cent (77%) of the patients had visited a gynaecologist within 1 year and only 4.3% were lost to follow-up. We found that 25.2% of the patients had a low-grade lesion or worse (CIN 1+) and 10.2% had a high-grade lesion or worse (CIN 2+), among which were four malignancies. The only variable associated with CIN or worse was age. Women under 40 years were found to be at a higher risk.

CONCLUSION

This finding may be used for prioritizing women for colposcopy on the basis of their age. More stringent use of the diagnosis of BNC, higher thresholds for colposcopically directed biopsy and introduction of HPV triage, combined with more specific new techniques or combination of techniques such as molecular markers for P16, MIB-1 and L1 may reduce the unnecessary high referral rate and over treatment of healthy women.

Human papillomavirus testing on self-sampled cervicovaginal brushes: An effective alternative to protect nonresponders in cervical screening programs

Women not attending cervical screening programs are at increased risk of cervical cancer. We investigated in these nonresponders to what extent offering self-sampling devices for cervicovaginal brushes for high-risk human papillomavirus (hrHPV) testing would induce participation and, if so, what the yield of precursor (i.e. CIN2 or worse) lesions following self-sampling would be. In addition, we assessed screening history of participants and costs per detected high-grade CIN2 or worse ("CIN2+") lesion in comparison to the regular program in the Netherlands. Nonresponders received a device for hrHPV testing (self-sampling group, n=2,546) or an extra recall for conventional cytology (control group, n=284). The percentage of self-sampling responders were compared with responders in the recall group. hrHPV positive self-sampling responders were invited for cytology and colposcopy. CIN2+ yield and costs per detected CIN2+ were evaluated. Active response was higher in the self-sampling than in the control group (34.2 vs. 17.6%; p<0.001). hrHPV positive self-sampling responders were less likely to have a prior screening history than screening participants (p<0.001), indicating that they are regular nonresponders. hrHPV prevalence was similar (8.0 vs. 6.8%; p=0.11), but CIN2+ yield was higher in self-sampling responders compared to screening participants (1.67 vs. 0.97%; OR=2.93, 95% CI 1.48-5.80; p=0.0013). Costs per CIN2+ lesion detected via self-sampling were in the same range as those calculated for conventional cytological screening (euro 8,836 vs. euro 7,599). Offering self-sampling for hrHPV testing in nonresponders is an attractive adjunct to effectively increase population coverage of screening without the adverse effect of markedly increased costs per detected CIN2+ lesion.

Chapter 9: Clinical applications of HPV testing: A summary of meta-analyses

BACKGROUND

More than ever, clinicians need regularly updated reviews given the continuously increasing amount of new information regarding innovative cervical cancer prevention methods.

MATERIAL AND METHODS

A summary is given from recently published meta-analyses on three possible clinical applications of human papillomavirus (HPV)-DNA testing: triage of women with equivocal or low-grade cytological abnormalities; prediction of the therapeutic outcome after treatment of cervical intraepithelial neoplasia (CIN) lesions, and last not but not least, primary screening for cervical cancer and pre-cancer.

RESULTS

Consistent evidence is available indicating that HPV-triage with the Hybrid Capture-2 assay (HC2) is more accurate (significantly higher sensitivity, similar specificity) than repeat cytology to triage women with equivocal Pap smear results. When triaging women with low-grade squamous intraepithelial lesions (LSIL), a reflex HC2 test does not show a significantly higher sensitivity, but a significantly lower specificity compared to a repeat Pap smear. After treatment of cervical lesions, HPV testing easily detects (with higher sensitivity and not lower specificity) residual or recurrent CIN than follow-up cytology. Primary screening with HC2 generally detects 23% (95% confidence interval, CI: 13-23%) more CIN-2, CIN-3, or cancer compared to cytology at cut-off atypical squamous cells of undetermined significance (ASCUS) or LSIL, but is 6% (95% CI: 4-8%) less specific. By combined HPV and cytology screening, a further 4% (95% CI: 3-5%) more CIN-3 lesions can be identified but at the expense of a 7% (95% CI: 5-9%) loss in specificity, in comparison with isolated HC2 screening.

CONCLUSIONS

Sufficient evidence exists to recommend HPV testing in triage of women with atypical cytology and in surveillance after treatment of CIN lesions. In the United States, recently reviewed knowledge has resulted in the approval of combined cytology and HC2 primary screening in women older than 30 years. However, in Europe, cytology-based screening still remains the standard screening method. The European screening policy will be reviewed based on the longitudinal results of randomised population trials which are currently underway.

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.

Determination of viral load thresholds in cervical scrapings to rule out CIN 3 in HPV 16, 18, 31 and 33-positive women with normal cytology

An increased high-risk human papillomavirus (hrHPV) viral load in cervical scrapings has been proposed as a determinant for high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer (> or =CIN 2), but data so far for HPV types different from HPV 16 are limited and inconsistent. In addition, a viral load threshold to distinguish hrHPV positive women without > or =CIN 2 still has not been defined. Here, we used baseline cervical scrapings of women with normal cytology participating in a large population-based cervical screening trial (i.e. POBASCAM) who were GP5+/6+-PCR positive for 4 common hrHPV types, i.e. HPV 16, 18, 31 or 33, as a reference to arbitrarily define various viral load thresholds (i.e. 25th, 33rd, 50th, 67th and 75th percentiles of the lowest viral load values) for distinguishing women having single infections with these types without high-grade CIN. Viral load assessment was performed by real time type-specific PCR. The viral load threshold values were subsequently validated on abnormal cervical scrapes of 162 women with underlying, histologically confirmed CIN lesions containing 1 of these 4 hrHPV types. All 59 women with CIN 3 had viral load levels that were higher than those of 33% of the women with normal cytology containing the respective hrHPV type detectable by GP5+/6+-PCR (i.e. higher than the 33rd percentile of viral load). By using this 33rd percentile viral load cut-off, sensitivity for CIN 3 of 100% (95% CI 93.9-100) was obtained. Hence, application of this viral load threshold would increase the specificity of HPV testing for HPV 16, 18, 31 and 33-associated prevalent CIN 3 without the cost of a marked reduction in sensitivity. In practice, on the basis of viral load analysis, a less aggressive management can be foreseen for 33% of the women with normal cytology participating in a population-based screening program who are GP5+/6+-PCR positive for HPV 16, 18, 31 or 33.

HPV testing in cervical screening

High-risk human papillomavirus (hrHPV) bearing cervical intraepithelial neoplasia (CIN) is considered, as the real precursor lesion of cervical cancer and persistence of an hrHPV infection is necessary for the progression to cervical cancer. This knowledge warrants the use of hrHPV testing as an adjunct to cervical cytology in population-based screening programmes and for monitoring therapy efficacy of high-grade CIN lesions. Replacement of cytology by hrHPV testing altogether is considered, but for this to be (cost-) effective, accurate information about the specificity of the hrHPV test is required. Additional test systems that can be used to stratify women with a positive hrHPV test are HPV genotyping, viral load analysis and hrHPV mRNA analysis. The need for HPV genotyping of cervical smears is illustrated by the increased risk for high-grade cervical lesions associated with HPV types 16 and 18. In particular, for women who have normal but persistently (>1 year) HPV18-positive smears, endocervical curettage is suggested (evidently considering the age and possible future pregnancies of the respective woman) because HPV18 is associated with glandular lesions in the cervix, which are difficult to detect by cytology.