Rise in oral cancers adds weight to HPV vax for boys

THE debate over extending HPV vaccination to males is set to reignite, after Australian research revealed the virus was responsible for an increasing number of oropharyngeal cancers.

The rate of HPV positive oropharyngeal cancer cases had more than tripled from 19% in 1987-90 to 66% in 2005-06, the authors in the Department of Health-funded study found. 

Around 475 new cases of oropharyngeal cancer were diagnosed in Australia each year from 2001 to 2005 and the number was increasing, they said. 

Smaller numbers of cancers at other sites, such as the larynx, were also HPV-related, the authors suspected.

Lead author Associate Professor Barbara Rose, from the department of infectious diseases and immunology at the University of Sydney, said the findings added “considerable impetus to the debate on extending vaccination to boys”. 

“There are potentially major social and economic benefits.”

Around 90% of the cancers were due to HPV types 16 and 18, similar to the rates for cervical cancer, she said.

“HPV is rapidly becoming, if it’s not already, the major cause of oropharyngeal cancer in the developed world. The increase is across men and women, and is most likely due to the increasing practice of oral sex.”

Professor Ian Olver, CEO of the Cancer Council Australia, said the increasing rate of HPV related oropharyngeal cancers added impetus to current arguments to extend vaccination to boys.

However, a spokesperson for the Health Department said: “While the paper is suggestive of an association and adds to the literature, it does not provide definitive evidence of a causal link. 

“In the absence of trial data, it is not known whether vaccination of males can either prevent transmission of human papilloma virus or oropharyngeal cancer.”

In a separate study, British researchers also noted similar increases in HPV-related oesophageal squamous cell carcinoma in European countries and the US.

“HPV-related oropharyngeal carcinoma seems to be a new and distinct disease entity, with typically younger patients,” they said.

Recent US research concluding male vaccination was not cost-effective (MO, 8 October 2009) was flawed in including a low incidence of HPV-related oropharyngeal carcinomas, they said.

Professor Luke Connolly, director of the Australian Centre for Economic Research on Health, said the most recent Australian cost-effectiveness modelling (in 2007) had concluded that “mass vaccination with a highly effective vaccine against HPV 16 has the potential to substantially reduce the incidence and prevalence of infection”.

Most evaluations  concentrated on cervical cancer only, or ignored herd immunity effects, making vaccination programs appear less cost-effective than they actually were, he added.

Vaccine online; BMJ online