Oral sex is being blamed for growing rates of throat cancers among Kiwi men.
Incidences of cancer of the tonsils and back of the tongue in men has more than doubled in the past 25 years.
The latest figures from the New Zealand Cancer Registry – 2013 – show 96 men and 26 women were diagnosed that year with oropharynx cancers nationwide.
Testing of 108 men treated for throat cancer at Waikato Hospital during a five-year span showed 90 per cent were HPV-related, and an expert says it is fair to say that similar proportions would be reflected nationwide.
The human papillomavirus is regarded as the most common sexually transmitted infection. The virus can cause cancers in both men and women, as well as genital warts.
From January 1, an improved HPV vaccine has been offered free to boys and young men. It has been offered for free to girls and young women since 2008.
The new vaccine protects against nine strains of the virus. The old protected against four.
Waikato DHB ear, nose and throat surgeon Dr Julian White is alarmed at the growing rates of HPV-related cancers in younger men.
Traditionally, throat cancers has been linked to smoking, he said, adding that “these were patients who were generally in poor health and hadn’t looked after themselves”.
“Now we’re seeing younger professionals who are otherwise healthy.”
Waikato Hospital ear, nose and throat surgeon Dr Julian White said increasing numbers of men are affected by HPV-related cancers.
One of main drivers behind the increased cancer rates is a change in people’s sexual activities.
People are also less likely to have had their tonsils removed.
“The three main risk factors are: male gender, early age of first sexual encounter, and increased number of sexual partners – in particular, oral sex partners,” White said.
Rates of cancer of the tonsils and back of the tongue is about four times more common in men than women. Men tend not be able to mount as strong an immune response to HPV.
“The mode of transmission is thought to be oral sex … and HPV infection of the genitals area is more common in women than in men.
“It would be remiss of me to not mention that studies do not support the notion that individuals who have had the HPV vaccine are more likely to engage in increased or risky sexual behaviour. In fact, there is some evidence the opposite is true.”
Dr Jane Morgan, clinical director of the Hamilton Sexual Health Clinic, said population studies in the United Kingdom and the United States show younger people tend to have more sexual partners than previous generations and are more likely to engage in oral sex.
The Health Ministry is currently analysing data from a population survey which looks at New Zealanders’ routine sexual behaviour.
An adolescent health survey showed most young people consider oral sex normal.
“Saying people have more sexual partners sounds quite judgmental, but it actually reflects the fact people are getting married much, much later in life,” Morgan said.
“The numbers have increased from, say, five partners to somewhere around 10 to 15. That may not sound like very much, but if everyone is doing that, it just makes it much easier for the virus to spread.
“When we say oral sex has become routine and most people have a few more partners than, say, their grandparents did, it’s not massive, but it’s been enough to really drive high rates of infection.”
White is a member of the New Zealand HPV Project and said feedback from other professionals indicates education about HPV has a small impact on behaviour.
Hence the beauty of the vaccine. He endorses efforts to encourage boys and young men to take up the free HPV vaccine.
Despite the HPV vaccine having a good safety profile, misconceptions about its safety persist.
A World Health Organisation committee spent six years looking at the side effects of the HPV vaccine and concluded its benefits outweigh any risks.
The organisation said allegations of harm from vaccination based on weak evidence could lead to real harm when, as a result, safe and effective vaccines cease to be used.
In 2013, actor Michael Douglas said his throat cancer was caused by oral sex. He later said he regretted the embarrassment caused to his wife, Catherine Zeta-Jones.
Currently there is no HPV test to check people’s status.
“Unless you’re going to be sexually abstinent for your whole life, then chances are you’re going to be exposed to the virus,” White said.
The earlier people receive the HPV vaccine, the stronger their immunity.
Children under 14 need only two injections. Older children and young adults require three.
The vaccine is offered free to anyone aged nine to 26.
Morgan said people get the “most bang for their buck” if they get vaccinated before engaging in any sexual activity.
“By sexual activity, we don’t mean penetrative sex, we mean before you start to become sexually intimate. Parents might think, my kid doesn’t need this [vaccine] before they’re 17 or 18, but you get the most benefit from the vaccine if you have it before you have had any sexually intimate contact.”