A Michael Douglas interview in The Guardian caused waves when the publication reported that the "Behind the Candelabra" star revealed HPV, the human papilloma virus, to be the cause of his stage-4 throat cancer diagnosis in 2010.
"Without wanting to get too specific, this particular cancer is caused by HPV, which actually comes about from cunnilingus," Douglas allegedly told The Guardian.
Douglas, through his publicist, has said that the statement was misinterpreted: He wasn't saying that his cancer was caused by the sexually transmitted disease -- merely that many cancers like his are HPV-positive. As The Daily Beast points out, there is scant research evidence to directly link the act of cunnilingus with HPV infection. But regardless of the details of his own cancer, the actor is right about one thing: A growing majority of oral cancer cases are caused by HPV.
While most strains of HPV clear up on their own, the sexually transmitted disease is responsible for an array of cancers. As Douglas describes, it's true that oral sex is an avenue through which a person can contract HPV and especially the strains, HPV-18 and HPV-16, the latter of which is responsible for half of oral cancer cases, according to the National Cancer Institute. HPV-16, HPV-18 and some less-common strains can also cause cancers of the cervix, vagina, vulva, anus and penis.
Douglas' experience follows trends in cancer diagnosis, according to a January report from the American Cancer Society, which found a rise in oral cancer caused by HPV in both women and men. As the report said, as of 2004, 72 percent of oral cancer tumors were HPV-positive -- up from 16 percent of tumors in data collected between 1984 and 1989.
Previously, excessive drinking and tobacco use were the most common causes of the throat cancer Douglas developed, but HPV has replaced tobacco as the leading cause of throat cancers. HPV's rise as the leading cause of oral cancer is not just the result of growing rates of the virus -- it is also explained by drops in smoking, thanks to public health campaigns that describe the dangers of cigarette use.
HPV-16 and 18 are targeted by the vaccine Cervarix and are two of the four strains targeted by Gardasil, the other of the two approved vaccines against HPV. Gardasil is currently recommended for boys between the ages of 13 and 21 and both Cervarix and Gardasil are recommended for girls, aged 13 to 26, according to the Centers for Disease Control and Prevention. HPV-6 and HPV-11, both of which the Gardasil vaccine immunizes against, cause about 90 percent of genital warts cases.
Despite the growing rates of oral cancer, cases like Douglas' are still relatively rare, with about 7,100 new cases each year, reported USA Today. But that doesn't mean oral HPV infection is rare: According to a 2012 study of Americans, aged 14 to 69, about 10 percent of men and 3.6 percent of women currently have an oral HPV infection.
According to the CDC, there is no screening test to determine overall HPV status. While women are screened for HPV-associated cervical cancer via a Pap-smear test, other HPV-associated cancers don't have a specific screening test. Despite the fact that there are no uniform screening techniques for oral cancer, the prognosis for the disease is good, with an 80 to 90 percent survival rate, according to The Oral Cancer Foundation.
For more information, have a look at this infographic produced by the Mount Sinai Medical Center:
Source: Mount Sinai Medical Center