Finding the optimal HPV test for primary screening and triage in Latin America

In this blog, we speak to Dr Maribel Almonte Pacheco, Prevention and Implementation Group Head at IARC. Dr Almonte is the chief investigator on the ESTAMPA study (EStudio multicéntrico de TAMizaje y triaje de cáncer de cuello uterino con pruebas del virus del PApiloma humano; Spanish acronym).  This study aims to recruit 50,000 women across 12 study centres in nine Latin American countries. Its main aims are to evaluate the performance of different triage techniques to detect cervical precancer and to inform on how to implement HPV-based screening programmes in low and middle-income countries (LMIC).

Dr Almonte talks to us about the less well-known aims of the study and about the legacy she hopes the study will leave.

How is the ESTAMPA study progressing?

We are approaching the end of recruitment (scheduled for June 2021) and the evaluation of the various triage techniques is already well on its way (published studies include: Kasamatsu et al, Ferrera et al, Arrossi et al, Robles et al, Rodriguez et al).

We have now started looking ahead. We are aiming to carry out a second round of screening about 5 years after enrolment into the study. Although there have been many screening studies in Latin America there’s never been an assessment of a full, two rounds of cervical screening. This second round doesn’t include the evaluation of triage tests, because we need to focus on the next steps towards HPV-based cervical screening implementation. And we would like first to assess the feasibility of continuing screening long term. So, in 10 years we expect that maybe 1 or 2 of the countries involved will start or continue using HPV testing in primary care and try to scale up testing to deliver a national or a regional programme. Of course, not all centres can commit to a second screen and the pandemic has definitely made things even more challenging. But reassuringly some centres are very keen to continue.

How does the ESTAMPA study help build HPV screening capacity?

When we go to a new country or a new setting within a country we assess where they are in terms of HPV testing capacity and cervical screening overall, what training is needed, what resources are needed and how we can collaborate with them in order to get them to do their testing locally. We do this for each setting individually taking into account different characteristics and cultures. We build expertise locally from sample collection all the way through to confirmation of disease. At all study sites, we trained sample collectors, laboratory personal, data managers, colposcopists and pathologists.

Although screening services in Latin America are offered free of charge, in some very rural areas there may be no local clinics meaning women need to travel sometimes for hours and this in itself can be a barrier to screening. We have therefore also considered the need to train new health workers to be able to treat precancer using novel techniques or develop ways to transfer women to areas where the care facilities are.

In terms of testing capacity, although we choose laboratories that had some experience with various assays, none of them had experience using valid commercial tests for primary screening. Hence, we pretty much had to start from scratch. In some centres, we even had to buy equipment, in others where they were already using validated techniques we try to contribute to regular monitoring of the testing.

Through the study, we have also identified knowledge gaps. One of the main gaps we have is that we don’t have enough epidemiologists and statisticians. We’re working with the PAHO and WHO to provide epidemiological and analytical training to a small number of people with the view that they can then go back to their countries and fill the knowledge gap.

Aside from new triage and testing technologies what else are you hoping to research?

In some countries, the people collecting the screening sample were also trained on visual inspection. We know that visual inspection is very subjective and therefore variable. However we are keen to facilitate a visual evaluation of the cervix using novel technology outside an urban setting, and we also want to promote that those evaluations are done by a non-specialist. There are a few new colposcopy devices on iPhones or handheld colposcopes and promising AI platforms which we are interested in evaluating.

We’re going to start exploring the use of these colposcopes to carry out a visual inspection, this is not yet been incorporated into Estampa but we’re already collecting the photographs and evaluating them for treatment. These photographs can also contribute and support initiatives on artificial visual evaluation (AVE) techniques. That’s why anyone we train to collect a sample we also train in visual inspection, particularly in settings with less specialist capacity.

Are you going to look at the feasibility of using self-sampling?

We’re always looking for ways to reduce the number of screening visits, and one way to do that could be self-sampling. However, the way to implement self-sampling in Latin America will be different for each county and may not be feasible in every country at the moment. In places like Argentina where self-sampling has been implemented, health workers are going door to door to offer the self-sample. This approach is not feasible in other parts of the continent- it’s too costly and there are not enough people to do this. You could, like in Europe, send the sample by post but that doesn’t work either because post offices are not available in many countries. In fact, there are many areas where addresses do not exist, for instance, so the way to identify a house could be “the green house between the church and library”.  Post services like in high-income countries are very scarce in the region.

We feel that for Estampa we would like to try to get women to attend the clinic to collect the self-sample and once there we would offer a private space in the clinic where they can take the sample.

However, with the COVID pandemic in full swing, we have to rethink this because in the event of an outbreak women may not be able to go to the clinic at all. Further after the COVID outbreak, everything must be disinfected all the time and women may not be happy to collect a sample inside the clinic. Perhaps most importantly, clinics may struggle to provide space for women to carry out the test if they are overwhelmed with patients with more urgent needs.

When you finish analysing the triage strategies, are you planning on issuing guidelines at the local level as to what the most appropriate strategy is?

IARCs work is focused on the research aspect and doesn’t develop guidelines per se- the guidelines are developed by the WHO. At IARC, we offer evidence gathered through rigorous research, we also offer technical support if requested. However, we do have a very close collaboration with the WHO and participate in developing WHO guidelines as experts. In addition, the WHO has a different relationship with countries- they can start the conversation encouraging countries to adopt initiatives that we have proven work and are feasible.

I think our final results will show that different strategies work for different countries. Even within a country, there will probably be more than one triage tests suitable for different settings. We plan to have conferences and meetings to explain our results and to see what we can do further.

What do you hope will be the legacy from ESTAMPA?

I hope we can leave behind a screening initial platform for participating countries to build on. By platform I mean training people, even if it only a small group comprised of people at a single university or at a particular clinic, it’s giving them know how to reproduce and scale up HPV based cervical screening programmes.

I’ve been working in cervical screening for many years. There are other projects which I’m involved in, based in Africa and Latin America, but for the first time, I’ve really found two things that give me joy.

The first one is we have established a group of highly motivated people committed to a common goal. Even if this group doesn’t have the power to do the scale-up job, they certainly can push others to get the job done. Over the years and since I was very young, I was involved in screening in Peru, my home country, and I remember seeing people in their 20s laughing at meetings saying, “This is another meeting where nothing will happen” I am happy to say that is definitely not the case now.

The second thing, I think, personally, is that we’ve discovered people in Latin America that could be the next generation of researchers, the next generation of people empowered on cancer prevention and working to reduce these inequalities we face in these countries.

Furthermore for the first time, as well, the worldwide scenario is helping us, because we have the commitment of many international organisations, and the WHO cervical cancer elimination initiative, and countries have already committed to action.

The views expressed are those of the author. Posting of the blog does not signify that the Cancer Prevention Group endorse those views or opinions.

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