Cervical cancer prevention through screening and vaccination
Silvia de Sanjose – Institut Catala d’Oncologia, Barcelona, Spain
A lot can be done about human papilloma virus and about cervical cancer, can you give me the facts on this? You’ve done a big study, a world-wide study, what did you find about to what extent you can prevent cervical cancer?
What we find is that world-wide there are two human papilloma virus types that are common all over the world and that we now have a vaccine to prevent these types, these are the HPV types 16 and 18. These types cause over 70% of all cervical cancers wherever you are in the world. We know now that by vaccinating young girls before they acquire the infection, we could reduce about 70% of these cancers.
Now, you can also reduce the incidence of these cancers by screening, that’s another alternative, isn’t it?
What we can do with the screening is to detect early lesions because this cancer has a long latency period in which we can interfere by exploring the cervical cells through a microscope or through molecular biology tests that detect the persistence of that virus and then we can act before there is a disease, that it’s incurable.
What practically do you need to do? It’s clear that if you could vaccinate everybody the disease would sort of go away, or at least 70% of it would, but in practical terms what can you do? How do you persuade governments and the public to go along with all of this?
We are working a lot in the developing world trying to introduce the vaccine because we think that that’s the best strategy when you don’t have enough infrastructure. In countries in which screening has been going on for the last fifty years, we are aiming to reduce the screening uptakes in women that will have been vaccinated because the burden of disease would have dropped dramatically. We are also working on improving our tools of screening so that women could go to the screening not every year but can go every five years using a very good detection method like detection of the viral DNA which is something that is now coming up front in many countries as a primary screening tool. So our scenario in Europe or in the US or in Australia is that we will vaccinate the young girls and then when they reach the age of 20-25 we’ll start thinking about the screening but screening in much wider intervals. Meanwhile, until this cohort of vaccinated girls are not available as adult women, we have to keep on working with the screening in adult women. We are trying now to improve and to introduce these new technologies so that our screening performs as best as possible.
So screening can perform really well because there was an issue about failing to detect cancers, wasn’t there? The new screening can be more effective, are you saying?
The screening has proven to be extremely good in countries in which the infrastructure allows to cover the large majority of women, let’s say over 90% of the women are covered with the screening, like in the northern countries or in the UK, then the impact of the screening is that the reduction of cervical cancer mortality can be up to 80%. But it’s very costly, to do that we have to keep on bringing women to our clinics regularly, every three years, every five years, it depends on the country but this is moving all the population to a screening action.
And even then some can slip through the net because it has been suggested that the women most at risk are the ones who are least likely to attend regularly for screening.
For me, the absence of screening is the major risk factor so obviously a woman that does not attend forces herself into the highest risk category.
So how do you help her?
Generally this is linked to lower educational awareness of prevention strategies, poverty and high parity, sometimes, of women, that they are very busy, that they had had many other gynaecological issues and they don’t feel like they have to go to their doctor again for a gynaecological examination. So many countries are now taking the strategies to reach the unreachable women by, for example, providing self-sampling tools that could facilitate the woman to examine herself, not having to go to the clinics, and calendrical systems, trying to gather these women through the general practitioners. There are possibilities that we can reach women but the best approach for equity is vaccination.
So good organisation on the screening will bring a yield; vaccination, though, has psychological issues and ethical issues, doesn’t it? It can be difficult to introduce, how do you propose encouraging countries, both the advanced countries and developing countries, to accept vaccination for girls and perhaps even for boys?
I think the HPV vaccine has been very much in the media, too much sometimes, but we need to take care of educating our population and showing the population and our professionals the large amount of data that’s showing the benefits of these vaccines. There are issues, there are limitations, we have not followed this vaccine for twenty years because it’s available since 2006 but we already know that the impact of these vaccines in precursor of cancer lesions is so high, is so relevant, is so important, that it could be unethical not to try to introduce this vaccine in our population.
Unethical maybe, but you need to win the psychological battle to get these messages over, don’t you? Not just with logic, how do you persuade people to take part in this?
There are many advocacy groups and we work, particularly in our group, we are developing a lot of tools to introduce to the professionals at any level, a lot of background material that they can read in an easy way and as well that they have tutors that can answer their queries so that there are no empty boxes there, that people can really ask without any problem and get the right answer, not influenced by industry or by commercial interests.
Finally, there really is a big problem, can you describe the inequity that exists all over the world with huge numbers of women still dying from cervical cancer and the basic take-home messages that you would like to leave people with?
It’s so dramatic to go to Africa or to some Caribbean countries and Latin American countries, not to say some Asian populations, that they don’t have access not even to an aspirin, that the women are left abandoned, alone, dying of their disease that will kill her for several years with a miserable condition. It’s a big problem when a woman of 45 years old dies because she leaves the children orphans and leaves the parents and grandparents orphans of this woman who was the important person in this household. This is a very common event that we see in Africa every day but as well we are seeing this in some groups of women in Europe and in the US, rich countries, that they still have groups of women that they don’t have access to this care and to this prevention.
And the main message you’d like to leave, is it the vaccines or screening?
I think we can do it and we have vaccines that can prevent disease and we have adult women who can access screening. Just one screening lifetime will be an important message to those women that have never gone to their gynaecologist.
Silvia, thank you very much indeed.
Thank you to you.