Throat Cancer and HPV – the researcher

Assoc Prof Karen Canfell is a researcher with the Lowy Cancer Research Centre at the University of NSW. HPV is her area of expertise. What does she want us to know about HPV and the vaccination program?

CAROL DUNCAN: Karen, your area of expertise is human papilloma virus and I understand there’s not just one but 100 or more?

ASSOC PROF KAREN CANFELL: That’s right, there’s a large number of types HPV that have been implicated in cancer but it’s really two of those types that are responsible for the vast majority of cancers, HPV 16 & 18 and those types are the ones that are included in the vaccine that is now available to us.

CAROL DUNCAN: I guess this is the point of this series this week is that we now have another cancer which is, in essence, preventable.

ASSOC PROF KAREN CANFELL: Yes, I think what we’re seeing with HPV is an incredible success story in cancer prevention. This started with the vaccination of girls and women in Australia. Because HPV has a very important role in cervical cancer and, in fact HPV is responsible for virtually all cervical cancers, the types we just mentioned (types 16 & 18) are responsible for about 70% of those cancers.

Five years ago, in 2007, we had the implementation of the National HPV Vaccination Program in girls and women in Australia and that’s really had incredible effects already. For example we’ve already seen a drop in the number of young girls infected with HPV, we’ve also seen a reduction in the numbers of high-grade abnormalities of the cervix which are the precursor to cervical cancer, and we’ve seen a reduction in anogenital warts which are also caused by different types of HPV which are also included in the vaccine.

So in terms of what’s happened in females, it’s just a remarkable story and we’ve really seen it play out in Australia before anywhere else in the world because Australia was one of the first countries to adopt the vaccine.

CAROL DUNCAN: And now it takes another step as of this year (2013) with the extension of the cervical cancer vaccine to boys.

ASSOC PROF KAREN CANFELL: That’s right. Again, Australia is one of the first countries to make this decision.

Last year, the Pharmaceutical Benefits Advisory Committee recommended that young boys are included in the National HPV Vaccination Program and that will roll out from this year. What that means is that it is going to provide incremental benefits to both girls and boys and I think what we have to remember here is that HPV is transmitted between males and females so vaccination of females was already going to have some beneficial effects for males ultimately because it would cut off the circulation of the virus in the population, but by including young boys in the program we have even greater coverage and we also have protection of the gay community, so I think this really does provide and important incremental step to protecting males even further against HPV infection and the cancers that can be caused by it.

CAROL DUNCAN: The cancers that HPV can cause in men are equally as horrific as cervical cancer.

ASSOC PROF KAREN CANFELL: That’s right, there is a whole range of cancers that HPV can cause in men and also in women in sites other than the cervix.

These include anogenital cancers but also cancers of the head and neck. These are an important set of cancers. I think the complication is that not all of these cancers are caused by HPV but still a significant fraction are and probably that fraction is increasing in the case of head and neck cancers.

CAROL DUNCAN: Dr Jonathan Clark mentioned that, and that so far researchers don’t know why the rate is increasing.

ASSOC PROF KAREN CANFELL: We can’t say definitively but it certainly seems that in Australia and the US that that is happening. A US study has recently shown that cancers of the head and neck maybe now about 70% of them could be attibutable to HPV, so that is a high proportion of those cases.

The other message we need to say here is that vaccination is a really wonderful thing and it’s going to have important long-term effects for men and women in Australia and in most countries which have implemented vaccination programs.

But for women in particular, it’s really important not to forget about cervical screening because that’s what is also protecting older, unvaccinated women against cervical cancer and really the two preventative mechanisms need to work together for the forseeable future.

The main message here is that the vaccination program in females has been incredibly effective. It’s about 73% coverage in young girls in Australia, so there still is one in four girls in Australia not being vaccinated so I think for parents of both young boys and young girls at school it’s really important to see this as a long-term wonderful gift that you can give to your children in terms of cancer prevention.

CAROL DUNCAN: I have watched six hours of throat cancer surgery, I can assure you you don’t want your children to go through that.

ASSOC PROF KAREN CANFELL: Yes I can imagine.

 * This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.