Overview of Cervical Screening Worldwide

September 8, 2006


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Dr. Saloney Nazeer: “In this limited time period, what I’ll try to do is give you an overview.  I’m afraid there’s not enough time to go into a detailed review of cervical cancer screening worldwide.  The overview is the burden of the disease, as we know it in different parts of the world looking at statistical values.  We’ll go through the characteristics of successful screening programs as we have learned from different countries that have implemented them and what the causes were of failures where it did not have an impact.  Then we’ll tell you how the problem is the siege and the solutions of the siege at the international expert level, i.e. the World Health Organization, and it’s other partners.  We’ll go on to giving you the actual reality, a real perspective from the experts within the countries where these guidelines are suppose to be implemented.  

So looking at the statistics, I like seeing them in the context of either gynecological cancers and, it is probably the most preventable form of major cancer today but still around 500,000 new cases and you can see how the women die of cervical cancer in the world.  If you look at the distribution around the world, the highest prevalence areas are mostly down south, this southern belt.  Now in the northern part, especially in this part of the northern countries where successful screening programs have managed to fade some of the colors here, I’m afraid over the last fifty years or so of cytology screening, around the southern belt either the colors are intensifying or there’s no change at all.  Having said that, how do we see the situation analysis as it stands today?  We’ll talk about the 80% of the world’s population as they reside in developing countries. 

Now according to World Health Organization’s analysis, 60% of all prevalent cancer cases are found in developing countries, and almost three-quarters of all new cases worldwide occur in developing countries where only 5% of world resources are available to be spent on cancer care.  The majority of these cases are seen at late stages where they are incurable so incidence often equates to mortality and, of course, the majority of population groups are not covered with any kind of cancer care let alone screening.  Particularly when we’re talking about cervical cancer, our analysis showed that at any given time period, 5% of women get screened in developing countries compared to 40% in industrialized countries.  Now having looked at the situation analysis, you don’t need to give justification that we do need to go in with some kind of screening strategies.  How do we all perceive when you say screening?  We all use it very frivolously, so this is a textbook definition, it goes – ‘screening is a presumptive identification of unrecognized disease or defect by means of test, examination, or other procedures that can be applied rapidly.’  Now in simple English, it is picking up a disease process before its cancerous stage in a symptomatic population.  Let’s not lose the perspective of the objective of the screening, which we often do, which is basically to reduce risk of death from the disease and ultimately the incidence, hopefully.  Like I said earlier, we jotted down characteristics of organized screening programs from examples of countries, which did successfully manage to do that.  

Now we realize that correct identification of the target population is a very important feature, then of course high coverage.  We thought 80% as the minimum coverage if you’re going to have any kind of impact by a screening program.  Similarly, having clear health objectives and having clear screening protocols was extremely important and adequate facilities, not just in the field but also at the institutional level, for diagnosis and treatment and follow-up of patients is extremely important.  Then you go on to information systems to document all that information which helps you monitor your program and, of course, you need indicators - process and outcome quality indicators for implementation of your program.  Then we looked at the examples of countries that unfortunately fail to have the impact they set out to have through their screening programs.  So we listed in order of importance as we recognized characteristics of failures in these programs.  The main reason was failure to reach the women at risk.  They were screening the same women again and again, and they were failing to reach the population coverage.  Then there is inadequate follow-up of abnormal results, now we’re talking about psychology based screening programs over here, and then excessively long screening intervals was another issue and lack of quality control in some countries.  

At WHO we looked at these other available control strategies for cancer control; we’re talking about generally all cancers here.  There’s no time to go through and explain in detail this slide, it is an important slide though, but what I would like to do is have a quick glance and look at the two most widely screened cancers in the world, mainly cervix and breast.  You’ll see if you screen, you can prevent 60% of incident cases and 60% of mortality.  Similarly, if you look at the time period where these different strategies can give you an impact if applied properly, you will see that screening is relatively in a limited time period and can give you very beneficial results.  I remember a quote from a very good friend, and I couldn’t agree more that screening is like a seatbelt, there are no guarantees but it definitely provides some protection.  Now where do we go from here?  Having looked at the situation analysis, we’ve established that, yes, we do need to give guidelines and screening is necessary.  The World Health Organization produces guidelines, technical and managerial for the countries to follow them up in the national program but this time we decided that we’ll have a more collaborative approach to the whole thing so we started with the WHO study group in 1993 which broadened its mandates.  

We started an umbrella project of an international network, which is a consortium of UN and non-UN organizations, governmental and non-governmental faculties of different universities, and the idea was to get everybody’s experience together.  We had a Consensus Conference with all of these collaborators and we reviewed the existing WHO guidelines in the light of the latest research, and this Consensus Conference happened last year.  After having reviewed in the light of the recent research, eighty-five experts from different countries came and presented.  This is what WHO’s guidelines looks like - information, education, and communication coupled with an organized screening program are the way to go.  We recognize Pap smears as the proven method today, then the WHO step-up approach which we have been advocating for a long time still holds fast especially taking into account the different resource settings in different parts of the world.  So we recommend, i.e. the World Health Organization, to screen every woman at age 45 if your resources are really limited.  To move unto ten year screening and those are the age groups 35, 45, 55 if you have better resources and you can manage that.  Then if further resources are available, you can go onto five year testing between age 35-59, and then of course the sky is the limit, as more resources and expedience becomes available you can go on to expand your screening program provided you have managed a minimum of 80% coverage of the population.  

Now what did the Consensus Conference add to these existing guidelines?  At the Consensus Conference the group reviewed different disciplines from problematic and political and socioeconomic issues right down to management of cervical dysplasia and the hottest subject, of course, was the different screening modalities.  Having reviewed research and expedience on various screening modalities which are being used currently around the world, the group came to the consensus that visual inspection with acidic acid and human papilloma virus detection does hold a future promise, either as an alternative, adjunct, two Pap smears, or as follow-up of patients after treatment.  However, the data was limited, yet sensitivity was quite impressive but these techniques need to be evaluated in prospective randomized control trials and our colleagues today on the panel, especially Professor Jack Cuzick, will be mentioning more about those trials to you.  We also reviewed the situation regarding HPV vaccines and where we stand and what we are going to have to offer in the future.  I’m sure all of you are aware by now there are prophylactic and therapeutic vaccines being extensively tested out but our analysis showed in 1999 that vaccines are not yet available commercially to be applied in the population.  It will take a year, especially for the prophylactic vaccine to be evaluated, and we do not have any clear effective administration of all these vaccination programs.  Similarly, we do not have yet estimates for compliance to said programs, now this analysis was based on our experience with the hepatitis B vaccine, and I’m sure you’re all familiar with that.  

So we have the guidelines and the consensus so where do we go from there?  For this umbrella project of international network with our collaborators we decided to take these guidelines into the country and have a discussion with them on practical issues and what they thought because everybody cannot come to the consensus conference.  Up till now, we have managed to cover four regions where the WHO’s regional offices are, and in all, WHO’s divided the world into six regions with its autonomous region offices.  That was South East Asia, Eastern Mediterranean, Africa, Europe and Central Asian countries so that counts to be about 137, that’s more than half of the 200 registered countries of the United Nations and more than half of the 6 billion population so the things you’re going to get is from that.  Now I’m sorry this is a pretty busy slide but don’t worry about that.  Let me just highlight a couple of points we need to remember here.  We did discuss with them, like I said, the same disciplines we discussed in China and the WHO guidelines, the highlights of all of these discussions with these experts from the countries, while the reality is that in most of these countries there are not any existing screening programs and there is no national commitment at this stage.  That is quite understandable for them to prioritize cervical cancer screening when they’re already overburdened with other disease issues and economic issues.  To be fair to different screening modalities, we put them on the table once again to discuss with them.  We discussed with them in terms of training required to implement them, their validity, sensitivity and specificity of the known modalities, technology required, cost implications, and problematic complications which we call links.  Now the thing to remember here is Pap smears seemed to fare the best of all of them but another important thing which I would like to highlight in this slide is that there’s no one single test to date which will fulfill the criteria of a perfect screening test.  It’s absolutely impossible, so we have to give and take others.  

Now this would sort of wrap up my whole overview - this is a schematic diagram we made at the World Health Organization based on experience from countries who have had successful programs, namely Finland, British Columbia, and the United Kingdom.  We have extrapolated to draw the scenario that exists today between developing and industrialized countries.  Now as you will see, this is where developing countries are today and this is where industrialized countries were at the turn of the last century in the 1920’s.  As you will see, the major impact on the reduction of mortality was achieved before any screening programs were introduced mainly through increasing ovarian awarness amongst women through health education programs and availability of basic standardized clinical facilities.  When organized screening programs were introduced in these countries in 1960, yes, there was an impact but not as comparable to other disciplines.  The point we are trying to make here is that we invariably fall into the path of just discussing one aspect in the whole picture of cervical cancer control and that is what screening modality to use.  Yes, it is important but more importantly you have to consider that in the context of all other important competence of a successful screening program.  In conclusion, all I’d like to say is that the decision to establish a cancer screening program depends not only on the factual evidence but also on whose values of benefit, harm, and cost prevail.  We have to reach a compromise between longevity and quality of life and the cost implications.  I thank you all very much and I thank FIGO and the secretariat for letting me share this experience with you.  Thank you very much for your attention.”