Jan 30, 2012
“ It is important for health care providers to know that people without the traditional risk factors of tobacco and alcohol use can nevertheless be at risk of oropharyngeal cancer ”
Dr Gypsyamber D'Souza, study author
The Johns Hopkins study took blood and saliva from 100 men and women newly diagnosed with oropharyngeal cancer which affects the throat, tonsils and back of the tongue.
They also asked questions about sex practices and other risk factors for the disease, such as family history.
Those who had evidence of prior oral HPV infection had a 32-fold increased risk of throat cancer.
HPV16 - one of the most common cancer-causing strains of the virus - was present in the tumours of 72% of cancer patients in the study.
There was no added risk for people infected with HPV who also smoked and drank alcohol, suggesting the virus itself is driving the risk of the cancer.
Oral sex was said to be the main mode of transmission of HPV but the researchers said mouth-to-mouth transmission, for example through kissing, could not be ruled out.
Most HPV infections clear with little or no symptoms but a small percentage of people who acquired high-risk strains may develop a cancer, the researchers added.
Study author Dr Gypsyamber D'Souza said: "It is important for health care providers to know that people without the traditional risk factors of tobacco and alcohol use can nevertheless be at risk of oropharyngeal cancer."
Co-researcher Dr Maura Gillison said previous research by the team had suggested there was a strong link.
But she added: "People should be reassured that oropharyngeal cancer is relatively uncommon and the overwhelming majority of people with an oral HPV infection probably will not get throat cancer."
A vaccine which protects against cervical cancer caused by HPV strains 6, 11, 16 and 18, and also against genital warts is available and the researchers said the study provided a rationale for vaccinating both girls and boys.
But whether the vaccine would protect against oral HPV infection is not yet known.
Dr Julie Sharp, science information officer at Cancer Research UK, said: "There is conflicting evidence about the role of HPV, and this rare type of mouth cancer.
"As this was a small study, further research is needed to confirm these observations."
"We know that after age, the main causes of mouth cancer are smoking or chewing tobacco or betel nut, and drinking too much alcohol." (Reference: Entire article http://news.bbc.co.uk/2/hi/health/6639461.stm)
MORE MEN "HAVE ORAL CANCER VIRUS"
Oral human papillomavirus (HPV) infection is more common among men than women, leading to an increased risk for men of head and neck cancers, a US study suggests.
The Journal of the American Medical Association (JAMA) study assessed around 5,500 people aged 14 to 69.
Around 10% of men had oral HPV, compared with 3.6% of women.
HPV causes the majority of cervical cancers, as well as genital and anal - and head and neck cancers.
Smoking and drinking are significant known risk factors for head and neck cancers. But oral HPV infection increases cancer risk by around 50%, according to the research team from Ohio State University Comprehensive Cancer Center.
They say the incidence of head and neck cancers has significantly increased over the last three decades, and HPV has been directly implicated as an underlying cause.
The researchers used data from a cross-sectional study as part of the 2009-10 National Health and Nutrition Examination Survey.
They all provided a skin cell samples for testing from their mouths, and were interviewed about their lifestyles and sexual history.
Overall prevalence of oral HPV infection was 7%.
Prevalence of HPV increased with lifetime or recent number of partners for any kind of sex, vaginal sex, or oral sex.
Writing in JAMA, the team led by Dr Maura Gillison, said their findings should influence research into the existing HPV vaccines and how effective they could be in preventing oral cancers.
"Vaccine efficacy against oral HPV infection is unknown, and therefore vaccination cannot currently be recommended for the primary prevention of oropharyngeal cancer.
"Given an analysis of US cancer registry data recently projected that the number of HPV-positive oropharyngeal cancers diagnosed each year will surpass that of invasive cervical cancers by the year 2020, perhaps such vaccine trials are warranted."
Jessica Harris, health information manager at Cancer Research UK, said: "As we learn how common HPV infections in the mouth are, and how they are passed on, we can understand more about who is most at risk and how people can reduce the risk of HPV-related cancers.
"Although there isn't yet any evidence to show whether HPV vaccination is effective at preventing oral HPV infections, results like these are vital to help inform prevention programmes in the future." (Reerence : Entire Article from http://www.bbc.co.uk/news/health-16746619)