ABSTRACT
OBJECTIVE OF THE PROJECT: Purpose of this Report is to evaluate the impact of the introduction of liquid-based cytology (LBC) in cervical cancer screening in terms of efficacy, undesired effects, costs and implications for organisation. EFFICACY AND UNDESIRED EFFECTS: LBC WITH MANUAL INTERPRETATION: The estimates of cross-sectional accuracy for high-grade intraepithelial neoplasia (CIN2 or more severe and CIN3 or more severe) obtained by a systematic review and meta-analysis published in 2008 were used. This review considered only studies in which all women underwent colposcopy or randomised controlled trials (RCTs) with complete verification of test positives. A systematic search of RCTs published thereafter was performed. Three RCTs were identified. One of these studies was conducted in 6 Italian regions and was of large size (45,174 women randomised); a second one was conducted in another Italian region (Abruzzo) and was of smaller size (8,654 women randomised); a third RCT was conducted in the Netherlands and was of large size (89,784 women randomised). No longitudinal study was available. There is currently no clear evidence that LBC increases the sensitivity of cytology and even less that its introduction increases the efficacy of cervical screening in preventing invasive cancers. The Italian randomised study NTCC showed a decrease in specificity, which was not observed in the other two RCTs available. In addition, the 2008 meta-analysis observed a reduction - even if minimal - in specificity just at the ASC-US cytological cut-off, but also a remarkable heterogeneity between studies. These results suggest that the effect of LBC on specificity is variable and plausibly related to the local style of cytology interpretation. There is evidence that LBC reduces the proportion of unsatisfactory slides, although the size of this effect varies remarkably. LBC WITH COMPUTER-ASSISTED INTERPRETATION: An Australian study, based on double testing, showed a statistically significant increase of the sensitivity for CIN2 or more of LBC with computer-assisted interpretation vs. conventional cytology with manual interpretation. However, an English RCT estimated that LBC with computer-assisted interpretation has a lower sensitivity than LBC with manual interpretation. COST AND ECONOMIC EVALUATION: In the current Italian situation the use of liquid-based cytology for primary screening is estimated to increase the costs of cytological screening. Liquid-based cytology needs shorter time for interpretation than conventional cytology. However, in the Italian situation, savings obtained from this time reduction and from the decreased number of repeats due to unsatisfactory slides are not currently sufficient to compensate the cost increase due to the prices currently applied by producers and to a possible greater number of colposcopies caused by LBC. In any case, at current prices, cost is estimated to increase even when assuming a referral rate to colposcopy with LBC similar or slightly lower than that with conventional cytology. For the costs of computer-assisted interpretation of liquid-based cytology, readers are referred to the relative HTA report (Epidemiol Prev 2012;36(5) Suppl 3:e1-43). ORGANISATIONAL AND ETHICAL ASPECTS: Ethical, legal and communication problems are judged to remain unchanged when compared to screening with conventional cytology. After having used the test for some time, interpreters prefer liquid-based to conventional cytology. Reduced time for interpretation makes the adoption of LBC a possible approach to deal with shortenings of cytology interpreters which is happening in Italy. However, alternative solutions, such as computer-assisted interpretation of cytology and the use of HPV as primary screening test, should be considered. Liquid-based cytology allows performing molecular tests, in particular the HPV test. This property allows triaging women with borderline or mild cytology by "reflex" molecular or immunocytochemical tests with no need to recall them. LBC sampling can be used also if HPV is applied as the primary screening test, allowing "reflex" triaging of HPV positive women by cytology with no need to recall them nor to take two samples, one for HPV testing and one for conventional cytology. This represents a remarkable advantage in terms of organization. However, costs are high because only 5-7% of women screened with this approach need interpretation of cytology. In addition, HPV testing with the Hybrid Capture assay on material preserved in LBC transport media needs a preliminary conversion phase, which limits the use of LBC for triaging HPV positive women. It is advisable that in the near future industry develops sampling/transport systems that allow performing both the HPV test and cytology or other validated triage tests without additional manipulations and at sustainable costs.
Subject(s)
Papillomavirus Infections/diagnosis , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Neoplasms/diagnosis , Vaginal Smears/methods , Alphapapillomavirus , Colposcopy/economics , Cost-Benefit Analysis , Cross-Sectional Studies , Cytological Techniques/economics , Early Detection of Cancer , Female , Humans , Italy/epidemiology , Mass Screening , Meta-Analysis as Topic , Papillomavirus Infections/complications , Papillomavirus Infections/economics , Papillomavirus Infections/virology , Predictive Value of Tests , Randomized Controlled Trials as Topic , Sensitivity and Specificity , Uterine Cervical Neoplasms/epidemiology , Uterine Cervical Neoplasms/virology , Vaginal Smears/economics , Uterine Cervical Dysplasia/epidemiology , Uterine Cervical Dysplasia/virologyABSTRACT
UNLABELLED: OBJECTIVE OF THE PROJECT: The introduction of the HPV test as a primary screening test will cause important changes in the screening system based on cytology. The purposes of this report are: to define the best screening policies with HPV-based screening on the basis of the resulting efficacy and of undesired effects; comparing them to cytology-based screening; to identify their best conditions of application; to evaluate economic cost, feasibility and impact on the organisation of services of such policy in the Italian situation. CONTENTS: This report contains a section on efficacy and undesired effects based on a systematic review of literature conducted in strict coordination with the preparation of a supplement to the European Guidelines for quality assurance in cervical cancer screening. This chapter corresponds to a preliminary version of the chapter of the European Guidelines on primary screening with HPV. The sections on costs, impact on organisation, and social, ethical and legal impact reflect the Italian situation; they are based on a review of the available Italian data (including unpublished data, mainly from on-going pilot projects) and on a structured analysis of what will result if the proposed protocol is applied to the Italian situation. RESULTS: Efficacy and undesired effects. There is clear scientific evidence that a screening based on validated tests for the DNA of oncogenic HPV as primary test and applying an appropriate protocol is more effective than screening based on cytology in preventing invasive cancers of the uterine cervix. In addition, it entails a limited--if any--increase of the undesired effects both in terms of unneeded referral to diagnostic work-up and in terms of over-diagnosis and consequent overtreatment of spontaneously regressive lesions. The crucial elements of such protocol are the followings: HPV-positive women are not to be directly referred to colposcopy, but the use of triage systems is essential. The currently recommendable method is based on performing cytology in HPV positive women. If the result of this test is abnormal, the woman is immediately referred to colposcopy; if cytology is normal, the woman is invited to repeat a new HPV test after one year. In case such a test is still positive, the woman is referred to colposcopy; in case of negative result, the woman will be re-invited for a new screening round at the regular interval. In organised population-based screening programmes the interval after a negative primary HPV test should be at least 5 years. There is evidence that the 5-year cumulative risk of high-grade CIN after a negative HPV test is lower than the 3-year risk after a normal cytology. On the other hand, the probability of unneeded colposcopies and treatments would plausibly be relevant with 3-year intervals after a negative HPV test. HPV-based screening should not start before 30-35 years. There is evidence that below 30 years HPV-based screening leads to an increased overdiagnosis of CIN2 that would regress spontaneously, with consequent overtreatment. Some increase in overdiagnosis is plausible also between 30 and 34 years. Below such ages, cytological screening is the recommended test. Only tests for the DNA of oncogenic HPV, validated according to the European guidelines as for sensitivity and specificity for high-grade lesions, should be applied. There is no evidence that double testing with cytology and HPV is more protective than stand-alone HPV as primary test, although it entails a small and not relevant increase in sensitivity vs stand-alone HPV. On the contrary, there is evidence that double testing causes a substantial increase in referral to colposcopy and a decrease in its PPV. For this reason, if HPV is used as primary screening test, it is recommended not to add cytology in parallel. Cost and economic evaluation. It is estimated that, if the protocol described is applied, in the current Italian situation the overall costs of HPV-based screening are lower than those of conventional cytological screening applied at the current 3-year intervals, although the cost of each screening round is higher. Impact on organization. For reasons of quality and cost, both the interpretation of cytology and HPV testing require a centralisation. This need is particularly strong, in terms of costs, for HPV test execution. It is therefore recommended to perform the HPV test in a limited number of reference laboratories of large size. This also makes monitoring and evaluating the spontaneous activity easier. HPV-based screening entails problems of organisation related to the need of triage, to complex protocols and to reconversion of the activities of cytological interpretation. Social, ethical and legal impact. The communication of the result of the HPV test to women, particularly if positive, is a further crucial aspect in order to reduce not only the emotional impact, but also the possible risks that women are inappropriately managed or lost to follow-up. Great efforts must be put in the education of healthcare professionals, both directly involved in organised programmes or not, particularly private gynaecologists and general practitioners. RECOMMENDATIONS: In conclusion, the crucial requirement to introduce HPV-based screening programmes is the capacity to guarantee the application of appropriate screening protocols. If protocols do not respect the criteria described above they can cause relevant increase of undesired effects and costs compared to cytology-based screening. Therefore they should be avoided, except in studies able to provide clear evidence about human and economic costs. For this purpose, correct education and information both to healthcare professionals and to the population is needed. In the Italian situation, where organised screening and a relevant spontaneous activity coexist, their interaction is crucial. Actions directed to integrate them and to guarantee as more uniformity of interventions as possible are needed, in particular through the integration of registries and thorough monitoring and a progressive homogenization of protocols. In order to grant the safety of transition, it is needed that the HPV-based organised screening activities are strictly monitored and that the National Centre for Screening Monitoring (ONS) ensures coordination. Knowledge about HPV based screening is still rapidly evolving. It is possible that currently on-going researches suggest changes to the optimal protocols in the next few years, particularly as for the management of HPV positive women. In addition, studies on the validation of new assays were recently published and others are expected. It is suggested to exploit the organised screening activity to produce scientific evidence, in order to clarify the still uncertain aspects of optimal protocols. Different protocols in terms of screening intervals, age of application and management of HPV positive women should be studied in the frame of controlled implementation, through multicentre projects coordinated by ONS. Finally, it is suggested the creation of a National working group to promptly update the recommendations for screening and the list of assays to be considered as validated. On the bases of the results obtained in the first vaccinated cohorts reaching the screening age, for the future, it will be crucial to deliver specific recommendations to the population vaccinated against HPV during adolescence.
Subject(s)
Human Papillomavirus DNA Tests/statistics & numerical data , Mass Screening/statistics & numerical data , Papillomavirus Infections/diagnosis , Precancerous Conditions/diagnosis , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Neoplasms/prevention & control , Uterine Cervicitis/diagnosis , Adult , Alphapapillomavirus/genetics , Alphapapillomavirus/isolation & purification , Colposcopy , Cost-Benefit Analysis , Female , Guidelines as Topic , Health Policy , Human Papillomavirus DNA Tests/economics , Humans , Italy/epidemiology , Mass Screening/economics , Mass Screening/legislation & jurisprudence , Mass Screening/organization & administration , Papillomavirus Infections/epidemiology , Papillomavirus Infections/virology , Precancerous Conditions/epidemiology , Precancerous Conditions/virology , Predictive Value of Tests , Program Evaluation , Truth Disclosure , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/epidemiology , Uterine Cervical Neoplasms/virology , Uterine Cervicitis/epidemiology , Uterine Cervicitis/virology , Uterine Cervical Dysplasia/epidemiology , Uterine Cervical Dysplasia/virologyABSTRACT
OBJECTIVE: causal relation between high risk Papilloma virus and cervical carcinoma is definitely ascertained. HPV test is suggested both as primary screening test and as triage test for selecting women who should undergo colposcopy examination. Evidence is clear for triage after ASC-US cytology. A recent study suggested the implementation after LSIL cytology in women 35 or older but the issue is controversial.We present a pilot study on the implementation of HPV test triage in the framework of cervical cancer screening. The study was conducted in respect to: participation, predictive value, and cost analysis, separately for ASC-US and LSIL cytology. DESIGN: HPV test was offered to women with Pap test result ASC-US or LSIL (35 and over), as an add-on to the "Prevenzione serena Screening Program" protocol. All samples were analyzed in the same specialized laboratory. HPV positive women were invited to colposcopy, negative will be invited at the scheduled interval for negative screening tests. SETTING AND PARTICIPANTS: Piedmont (NW Italy), LHAs of Novara and Verbano. In the 1-year study period 15,614 Pap tests were performed: 153 women were eligible for the triage. MAIN OUTCOME MEASURES: Participation at HPV test, HPV test results, costs. RESULTS: ninety two percent of women invited to HPV test actually participated: 66.9% of them were positive (52.8% after ASC-US and 82.8% after LSIL). Regarding colposcopy and histological results, CIN2+ were 9.4% of positive HPV tests in ASC-US group and 17.1% in LSIL group. Cost analysis showed limited differences between triage (offered after ASC-US and LSIL cytology) and traditional protocol. Triage is economically convenient when limited to women with ASC-US cytology. CONCLUSION: the pilot study demonstrated the feasibility of adding a triage phase with HPV test in cervical cancer screening protocol. Additional cost is balanced by the saving due to the reduction in the number of colposcopy exams: the process is economically convenient when limited to women with ASC-US cytology. When extended to LSIL cytology the marginal cost increases because of the higher prevalence of HPV positive results and total cost of triage with HPV test is close to the cost of immediate colposcopy referral.