Guidelines Chap. 115. December 2003

Chap. 1.Introduction

(of Chap. 1: Introduction to the European Guidelines for Quality Assurance in Cervical Cancer Screening)

by Ulrich Schenck (), 6 pages

Introduction to the European Guidelines for Quality Assurance in Cervical Cancer Screening

Frequency and Importance of Cervical Cancer

Cervical cancer is a major cause of mortality and morbidity world wide and remains a significant health threat for women in the Member States of the European Union. In addition to its frequency the age distribution with an early peak increases the practical importance of the disease.

Role of Cervical Cancer Worldwide

Some 400.000 women per year will fall ill with the disease worldwide (Chapter 2). For those with poor or no medical resources available, this may mean that they are likely to die of the disease. There are rather obvious differences among the countries world wide. Very high mortality values are found in e.g. in Columbia whereas low values are observed for Israel.

Role of Cervical Cancer in Europe

The death toll in the countries of the European Union is generally lower than the level observed in developing countries and has been declining in the last decades (Chapter 2). In many countries where cervical cancer screening is in place already, the success is demonstrated by a drastic decrease in incidence and mortality of cervical carcinoma. But the curves demonstrate plateaus, some of which seem to be at a not acceptably high level. Where cervical cancer data are available, these data indicate that in some countries the background incidence was rather high like in Germany or in Denmark. Such observations stress the importance of international comparison of data and cooperation of cancer registries.

Cytology has been widely used in Europe as Screening Method

Pap smear cytological screening is place in many European countries both as diagnostic and as screening method either in opportunistic or in screening programs. Cervical cytology screening is the method of choice also today.

Short Comment about Screening and Programs in Europa:

It is not known exactly how many Pap-smears are analysed in Europe per year. Estimations may be in the range of 45 Million per year. The number of Pap smears in Germany may be estimated in the range of 18 Million per year.

Success of Screening is Documented by Decreasing Frequency of Cervical Carcinoma in many Countries

The decreasing frequency of cervical carcinoma can be largely attributed to cytological screening in Europe. Also in other countries where Pap smear screening is in place, cervical cancer frequency has been drastically declining. Examples for other countries are Australia, Canada, Japan, Switzerland USA. The success of Pap smear screening is both documented for countries with screening programs as for countries with opportunistic screening and self referral of women.

The Pap-Test is the essential method for cervical cancer screening. At present there is no further recommended technique for primary screening of cervical cancer and its precursors.

Heterogeneity in Europe and Recommendations on Screening

Concerning cervical carcinoma and screening strategies there are striking differences throughout Europe. While in some regions cervical cancer screening is available since 30 or even more years, there are areas where screening is not available today. To reduce such differences in health care the European Commission recently recommended cancer screening in general under certain well defined restrictions: “Organised cancer screening should be offered to healthy people if the screening is proved to decrease disease-specific mortality and/or decrease the occurrence of advanced disease, if the benefits and risks are well known, and if the cost-effectiveness of the screening is acceptable. At present the following screening tests meet such requirements: pap smear screening for cervical abnormalities starting at the latest by the age of 30 and definitely not before the age of 20,mammography screening for breast cancer in women aged 50-69 in accordance with European guidelines on quality assurance in mammography, faecal occult blood screening for colorectal cancer in men and women age 50-74. “

Positive and negative Effects of Cervical cancer screening

Benefit of cervical cancer screening

The major benefits of cervical cancer screening is the detection and treatment of the precursors of cervical cancer with subsequent reduction in both incidence and mortality of the disease.

Adverse Effects of Cervical Cancer Screening

There is practically no harm to the patients by sampling the uterine cervix. Harm to patients may be related to under- and overcalling of cytological findings. Unnecessary follow up of cytological abnormalities may create anxiety, unnecessary interventions and bind medical professional resources. Therefore optimal quality must be in place at all levels, and quality control and continuous quality improvement is needed.

Informed Consent

Such potential adverse effects of screening should be clearly outspoken. When organised screening is offered seeking for a high level of compliance should be based on fully-informed consent of the participating women.

Reasons for Cervical Cancer Screening as the ideal Cancer Screening Target

A number of factors create a unique situation for screening for cervical disease:

  • Cervical cancer is a frequent cancer
  • The cervix can be reached easily
  • The cervical cytological smear is a simple text with high sensitivity and a very high specificity
  • Precursor lesions precede invasive cancer by many years
  • Survival of early stage carcinoma is favourable as compared to more advanced stages
  • Treatment of lesions is available and acceptable, whereas the cervix is a non-vital organ

For these reasons success of cervical cancer screening cannot be extrapolated to other cancers and their precursors. There is no comparable screening test for breast cancer screening or lung cancer screening.

High Expectations and Disappointment in a Potentially Avoidable Disease

The success of cervical cancer screening often lead to the assumption that cervical cancer is a totally avoidable disease. Unfortunately this is not the case. While most cervical cancers can be avoided, still cervical cancer exists and continued attention is needed. Especially in the countries with long history of screening any cervical cancer is a challenge for future improvement of cervical screening.

Cervical Cancer Screening with Cytology is not Perfect

In the last thirty years ample evidence has been collected that cytological screening can successfully reduce both incidence and mortality from cervical cancer. Such benefits are sufficiently clear cut and cost-effective for several European Member States, confirming the decision to embark upon national screening programs. Still deficits of screening are obvious. “Triumph and Tragedy” (Koss, 1989) are close together. Without clear analysis of the data no concepts for improvement can be developed.

Potential Mistakes:

  • Lacking participation
  • Participation at too long interval
  • Sampling error
  • False negatives due to missing cells in the screening progress.
  • Interpretational error of cytology
  • Mistakes in the follow up after cytological abnormalities.
  • Combinations of different mistakes

Fear of false negatives, if not directed by data analysis may lead to unnecessary over-consumption of Pap smears, which will nor solve the problem that participation has a social bias.

Need of Continuous Political support

To be successful, screening programs need a long term political commitment. Politicians must understand that cervical cancer is and will remain a major public health problem in the overseable future. Also, it must be understood that cervical carcinoma is a relatively rare disease due to to cervical cancer screening and not by its nature. Reduced awareness will result in increasing cervical caser cases. Continuous efforts for public information and education are needed, since when talking about the cervix in the public first an explanation on what is a cervix will be needed . Only then a detailed discussion is possible.

Details of political responsibility

Cervical cancer screening requires a far reaching political responsibility in order to be effective. This will entail the organisation of a suitable infrastructure, setting of screening policy, coordination of professional groups and economic programme evaluation. Medical expertise from all relevant fields of medicine is needed at all levels. Part of the political responsibility is also to clarify that the methods are not perfect and errors are inherent. Reaching an informed consent concerning participation and non-participation in cervical cancer screening should not be left to the local level alone.

Success of cytological screening leads to reduced political support

Today we are facing the situation that in a number of regions of the world cervical cancer screening has been so successful that cervical cancer is no more realised as major health threat. With this success, political support is reduced and infrastructure is declining.

Are screening Programs more Successful than Self-Referral Concepts?

Generally, from countries where self-referral is the traditional approach little information concerning the success of programs and the cost benefit relation can be extracted. The longer opportunistic self-referral cervical cancer screening is in place and the more successful it is, the less frequent the serious target lesions get. So, with time cost-benefit relation may get worse and a heavy over-screening of part of the female population will go undetected as will be the case with a major part of the female population not attending screening at all. Only a program can follow the classical sequence of plan, do, control and adjust. A program must be organised as to produce the data for adjustment and improvement.

Need of Quality Assurance

Planning screening may start with the idea to reduce cervical cancer mortality e.g. by a factor of ten. Provided such targets are set, the data will be needed to analyse the situation in the population. Without cancer registries and data collection such an effort is impossible. For this reason reading the chapter 2 (Chapter 2: Epidemiological guidelines for quality assurance in cervical screening) is very basic. Organisation and planning is not possible without thorough understanding the relevant methods (Chapter 3: Methods and techniques of cervical screening) with their advantages and shortcomings. Also potential modifications of cervical cytology like liquid based cytology and automated cytology screening are discussed in this chapter as well potential tests that might replace cytology provided more evidence gets available like HPV-testing. A suggestion for a Uniform Report Scheme for European Screening programs is included to promote uniformity of data collection and comparison. Good medical practise in the cytology lab is described in chapter 4 (Chapter 4: Laboratory guidelines for cervical screening). Quality assurance is needed at all levels: Approaches are presented in chapter 5 (Chapter 5: Quality assurance practices in screening laboratory). Screening cannot be really separated from patient management where abnormal results induce further follow-up. This is the basis to include a chapter on good practise in histology (Chapter 7: Quality assurance guidelines for pathology in cervical screening). Based on Quality assurance as presented in chapter 4, 5 and 6 certification and accredition of individuals, laboratories and screening programs. (Chapter 7: certification and accreditation of the screening process, and staff skills). Patient management (Chapter 8:Guidelines for management of women with cervical cytological abnormalities) is diverse. In chapter 8 Patient management is described according to the different results from cervical cytology. Handling of patients with abnormal smears can make a big difference concerning the cost-benefit relation, therefore data collection on treatment of screen-detected lesions (Chapter 9) is so important. Successful screening needs medical specialisation (Chapter 10: Guidelines for Training) at many levels. Especially in those fields which are subjective and need very specialised training like cytology or colposcopy, training and proficiency testing concepts must be in place.

Organised Cervical Cancer Screening: A Challenge

The introduction of organised screening where it is not yet available is a major health care challenge that can not be reached with a limited number of changes in the patient service. Underestimating the complexity of population screening might be the first step on a direction of failure. Many coordinated steps are needed also where cervical cancer screening is already performed on a high quality level. This will need both efforts from the political side as from medical and administrative personell. It seems to be more difficult to change a running self referral or opportunistic concept to a program as compared to starting screening in a new target area. Quality of screening cannot get to its optimum where quality of structure in health care organisation and activities is poor. Neither smear takers nor cytopathologists can compensate for deficits in the invitation system. A good organisation in the lab cannot compensate for lack of medical training. Without clear cut regulations, that in many places will have to include changes of laws regulating the work of cancer registries with feed back to labs, the organisation of randomised trials long term improvement might remain minimal. The European Council has invited the member states to report on the implementation of cervical cancer screening and its quality improvement. All members of the European Cervical Cancer Screening Network hope that there will be improvements to report on.

References

Historical Background

  1. Koss LG. The Papanicolaou test for cervical cancer detection. A triumph and a tragedy. JAMA 1989;261:737.
  2. Wied GL. History of clinical cytology and outlook for its future. In Wied GL, Keebler CM, Koss LG, Patten SF, Rosenthal DL (eds.) Compendium on diagnostic cytology, 7th ed. Chicago: Tutorials of Cytology. 1992:1.

Overview Contributions

Quality Assurance and Guidelines

  1. Coleman D., Day N., Douglas G., Farmery E., Lynge E., Philip J., Segnan N., European Guidelines for Quality Assurance in Cervical Cancer Screening, Europe Against Cancer Programme. European Journal of Cancer 29A(4), 1993.
  2. Wied GL, Keebler CM, Rosenthal DL, Schenck U, Somrak TM, Vooijs GP (Edit): Compendium on Quality Assurance, Proficiency Testing and Workload Limitations in Clinical Cytology, Tutorials of Cytology, Chicago, 1995.

Cancer Screening in Europe

  1. Advisory Committee on Cancer Prevention, Position paper. Recommendations on cancer screening in the European Union, Conference on Screening and early Detection of Cancer, Vienna 18-19 November 1999. E. Lynge, J. Patnick, S. Törnberg, J. Faivre, F. Schröder European Journal of Cancer, vol. 36, pp. 1473-1478,
  2. Cervical Cancer Screening in the European Union, special issue of European Journal of Cancer; Guest Editors: A. Linos, E. Riza, M. van Ballegooijen, EJC 2000 36/17 pp. 2175-2275.
  3. Commission of the European Communities. Proposal for a Council Recommendation on Cancer Screening. 2003/0093 (CNS). Brussels, 5th of May, 2003.
  4. European guidelines for quality assurance in mammography screening, 3rd Edition. Eds: N. Perry, M. Broeders, C. de Wolf, S. Toernberg. European Commission, Office for Official Publications of the European Communities, Luxembourg 2001, ISBN 92-894-1145-7.

The Cytological Report

  1. Schenck, U.; Herbert, A.; Solomon, D.; Amma, N.S.; Collins, R.J.; Gupta, S.K.; Jimenez-Ayala, M.; Kobilková, J.; Nielsen, M.; Suprun, H.Z.: Terminology - IAC Task Force Summary. In: Acta Cytol. 42 (1998), Nr. 1, S. 5-15

Effectivity

  1. Evidence Report: Evaluation of Cervical Cytology- Agency for Health Care Policy and Research. Duke University Center for Clinical Health Policy Research. February 1999.

Automation in Cytology

  1. Bartels, P.H.; Bibbo, M.; Hutchinson, M.L.; Gahm, T.; Grohs, H.K.; Gwi-Mak, E.; Kaufman, E.A.; Kaufman, R.H.; Knight, B.K.; Koss, L.G.; Magruder, L.E.; Mango, L.J.; McCallum, S.M.; Melamed, M.R.; Peebles, A.; Richart, R.M.; Robinowitz, M.; Rosenthal, D.L.; Sauer, T.; Schenck, U.; Tanaka, N.; Topalidis, T.; Verhest, A.P.; Wertlake, P.T.; Whittaker, J.A.; Wilbur, D.C.: Computerized Screening Devices and Performance Assessment: Development of a Policy Towards Automation. In: Acta Cytol. 42 (1998), Nr. 1, S. 59-68
  2. Tucker, J.H., Burger, G., Husain, O.A.N., Ploem, J.S., Schenck, U., Schwarzmann, P., Stenkvist, B.: Measuring the accuracy of automated cervical cytology prescreening systems based on image analysis. Report Eur 11454. Luxembourg: Office for Official Publications of the Commission of the European Communites, 1988, 52 S.
  3. Wied, G.L.; Bartels, P.H.; Bibbo, M.; Gupta, P.K.; Gurley, A.M.; Hilgarth, M.; Jiménez-Ayala, M.; Kato, H.; Knight, B.K.; McGoogan, E.; Medley, G.; Meisels, A.; Nishiya, I.; Nozawa, S.; Ramzy, I.; Reith, A.; Rilke, F.; Rivera-Pomar, J.M.; Rosenthal, D.L.; Schenck, U.; Verhest, A.P.; Vooijs, G.P.: Computer Assisted Quality Assurance - Editorial. In: Acta Cytol.(1996) Vol. 40 No. 1, S. 1-3

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