The sexually transmitted human papillomavirus (HPV) may be behind the sharp rise in cases of throat and mouth cancers among young American adults, researchers say.
In a new study, investigators from Henry Ford Hospital in Detroit analysed US government data and found that cancers of the base of the tongue, tonsils, soft palate and pharynx among adults aged 45 and younger increased by 60% between 1973 and 2009. Collectively, these cancers are called oropharyngeal cancer.
There was a 113% rise in the rate of these cancers among whites, but a 52% decrease among blacks during the study period. However, the five-year survival rate for these cancers remains worse for blacks than for whites and other races, the study authors found.
HPV, which can cause genital and anal warts, is the most commonly transmitted sexual infection in the United States. Usually, the immune system clears the infection, but in some cases the virus persists in the body. And persistent infection with certain HPV strains can eventually lead to cancer – with cervical cancer the best known.
HPV can also invade the mouth during oral sex. Those infections usually cause no symptoms, but a lingering infection with a cancer-linked strain can lead to oropharyngeal cancer.
The topic was given celebrity status this summer when actor Michael Douglas announced that his stage 4 throat cancer was the result of an HPV infection that he got from oral sex. Sexual revolution
In a hospital news release on the new research, study lead author Dr Farzan Siddiqui, director of the Head and Neck Radiation Therapy Program in the department of radiation oncology, said, "The growing incidence in oropharyngeal cancer has been largely attributed to the sexual revolution of the 1960s and 1970s, which led to an increased transmission of high-risk HPV."
Siddiqui added. "We were interested in looking at people born during that time period and incidence of oropharyngeal cancer. Not only were we surprised to find a substantial increase in young adults with cancer of the tonsils and base of tongue, but also a wide deviation among Caucasians and African Americans with this cancer."
Of the 1 600 patients in the study group, 90% were aged 36 to 44 and 73% were white. 50% to 65% of the patients had surgery to remove their tumours. Patients who had both surgery and radiation had the highest five-year survival rate, according to the report, which was scheduled for presentation at the annual meeting of the American Society for Radiation Oncology in Atlanta.
The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.
Recent research has shown that HPV exposure and infection increases the risk of oropharyngeal cancer independently of other important risk factors for the disease, such as tobacco and alcohol use, according to the US National Cancer Institute.
The US National Cancer Institute has more about oropharyngeal cancer.