Source: www.abc.net.au
Author: Lindy Kerin

Australian researchers say the human papillomavirus (HPV), which can cause cervical cancer in women, is now a leading cause of oral cancer in men in the Western world. The news has reignited debate over whether the HPV vaccine, which is free for young women, should also be offered to men.

A University of Sydney study shows that 60 per cent of throat and tonsil cancers are caused by the virus. “We’ve tested just over 300 cancers of the oropharynx, and the oropharynx includes the tonsil and the base of tongue and part of the pharangyl wall,” said Barbara Rose, an Associate Professor in research at the University of Sydney. “We’ve tested those for the human papillomavirus type-16 and type-18, which are the major cause of cervical cancer in women. “And we found a sizeable proportion are associated with those types. In fact, probably in excess of 50 per cent now.” Those figures from 2001 to 2005 increased to almost 60 per cent in 2006 and 2007.

Associate Professor Rose says head and neck cancers have traditionally been associated with older men and related to alcohol and smoking. She says these findings show that has now changed and most are due to the increasing practise of oral sex.

“We now know that there’s another subset, which is quite distinct biologically, which tends to affect younger people who don’t smoke and don’t drink, caused by human papillomavirus probably by sexual transmission,” she said. “And the types of papillomavirus that are associated are type-16 and 18, which are the major cause of cervical cancer.”

For the past two years, Australia has been rolling out the cervical cancer vaccine Gardasil to young women. It immunises them against HPV. Associate Professor Rose says the findings should prompt discussions about extending the vaccination program to boys.

“The paper that we just published gives some indication of the numbers of cancers that would be potentially preventable down the track by vaccinating boys,” she said.

Dr Jonathan Clark, a head and neck surgeon at Royal Prince Alfred and Liverpool Hospitals in New South Wales, says the rate of HPV cancers in men is increasing. “At the moment we’re trying to come to grips with what it means and how it changes our approach to managing these types of cancers,” he said. “The evidence is very strong that if you have the human papillomavirus causing this sort of cancer, in fact your prognosis is better than if the cancer is caused in the typical fashion, which is due to smoking.”

Extend vaccine to boys
Dr Clark says extending the vaccination to boys is worth considering and is worthy of further research, which could take some time.

“Tonsil cancers occur in an older group of patients. Though HPV tonsil cancers tend to occur in younger people who don’t smoke, but they develop over many years,” he said. “So it is going to take quite a bit of time to see whether the introduction of HPV vaccine actually has an effect of reducing the rate of tonsil cancer.”

But the director of the Australian Centre for Economic Research on Health, Luke Connolly, says the cost-effectiveness of extending the program to boys needs to be analysed.

“What needs to be done is the models that researchers like myself and others are using need to be extended to try to cover these additional types and the impact of the vaccine on these types,” he said.

“That’s not always particularly easy to do but there’s now sufficient data to allow us to start down that path to assess the cost-effectiveness of the vaccine for boys.”