Roughly one in nine US men has an oral infection of the cancer-causing human papillomavirus (HPV), more than triple the infection rate for women, a new study suggests. Most infections don't cause symptoms and go away on their own.
A person infected with HPV, which can be transmitted through skin-to-skin contact, may lead to cancer in several parts of the body, such as the throat, penis, vagina, and anus. A new study published this week in the Annals of Internal Medicine reveals that the mouths of many men are infected with HPV, often contracted through cunnilingus. And infection is most likely for those who have had multiple oral sexual partners, are gay or bisexual, or who also have genital HPV infection, a team of USA researchers found.
"We have the HPV vaccine approved for use in both boys and girls, which has the potential to decrease rates of HPV-associated cancers in the future", Deshmukh said by email. "But the low uptake of the vaccine among boys and disparities in the uptake remains a concern". Previous research suggests that rates of HPV-related oral cancer will surpass cervical cancer by 2020.
Statistics from a Canadian Cancer Society report last fall showed 1,335 Canadians were diagnosed in 2012 with HPV-related oropharyngeal cancer, and 372 died from the disease. The HPV vaccine is only recommended for people up to 26 years old, leaving out many men as too old to receive the shots.
"The rates of oropharyngeal cancer among men have risen more than 300 percent in the past 40 years making oropharyngeal cancer most common HPV-related cancer in the United States", Deshmukh wrote in an email.
While the HPV vaccine may help prevent these tumours, the vaccine is now only recommended for people up to age 26 and many men are too old to receive the shots. They found that overall, 11.5 per cent of men and 3.2 per cent of women had oral HPV infections.
Almost 2 million men had high-risk HPV 16, a strain that causes most of the cancers, Deshmukh said. But among those reporting same-sex sexual partners, 12.7 per cent of men and 3.4 per cent of women had high-risk infections. Almost all men and women will become infected with at least one type of HPV, a group of 150 related viruses, at some point in their lives, according to the US Centers for Disease Control and Prevention. One limitation of the study is that it relied on survey participants to accurately report on their sexual orientation and behaviours and stigma might lead some people to be untruthful, the authors note. Still, the findings highlight a need for better prevention among both men and women, said Dr. Erich Sturgis, a researcher at the University of Texas MD Anderson Cancer Center in Houston who wasn't involved in the study. This type was six times more common in men than women. "This can not be stressed enough".
It's also not clear why men have more oral HPV than women, she said.
"A lot of people are not really familiar with how devastating oral cancer is in general", she said, and most are "not knowledgeable about how HPV infection can actually cause these terrible cancers".
"We have methods to screen for cervical cancer; however, we still don't have ways to detect oropharyngeal precancer", Deshmukh said.
"It is also a very encouraging message to those who subsequently chose to have themselves or their children vaccinated", she added.
HPV vaccine prevents cancer, and "the data are remarkable", she said. However, boys and young men are far more likely to have the vaccine than their female peers.