Michael Douglas’s claim that oral sex led to his throat cancer is spurring calls to vaccinate more boys as well as girls against the human papilloma virus that causes the malignancy.
Merck & Co. (MRK) sells a vaccine called Gardasil to prevent cervical cancer caused by the sexually transmitted virus, known as HPV, in girls and boys. GlaxoSmithKline Plc (GSK) (GSK) also sells an HPV vaccine, though it’s not marketed for boys.
The virus infects four out of five sexually active people at some point in their lives and is known to cause cervical, vulvar, vaginal, penile and anal cancer. HPV may cause more cases of throat cancer in men than smoking, according to a 2011 report that predicted throat cancers linked to the virus would become more common than HPV-related cervical cancer by 2020.
“I very strongly believe we should be vaccinating boys,” said Anne Szarewski, clinical consultant and honorary senior lecturer at the Wolfson Institute of Preventive Medicine in London, in a telephone interview today. “By only vaccinating women, we’re implying that it’s not a problem for men. It’s a sexually transmitted virus, both men and women are involved, and we should be vaccinating both.”
Douglas, 68, an Academy Award-winning actor and star of films including “Wall Street” and “Fatal Attraction,” said in an interview with the U.K.’s Guardian newspaper that his throat cancer, diagnosed in 2010, was caused by oral sex, not smoking or drinking. About 10 percent of men are orally infected with HPV, compared with 3.6 percent of women, according to a 2012 study.
“Without wanting to get too specific, this particular cancer is caused by HPV, which actually comes about from cunnilingus,” Douglas was quoted as saying. “It’s a sexually transmitted disease that causes cancer.”
Douglas said he’s now cancer-free, and has check-ups every six months.
Cancers caused by HPV rose in the past decade in the U.S., where use of the vaccines remained low. Only a third of American girls ages 13 to 17 were fully vaccinated as of 2010, well below the 80 percent rate epidemiologists say is needed to significantly reduce the prevalence of infections. The vaccination involves three shots over six months, requiring parents to take their children to the doctor multiple times.
Boys vs. Girls
Some countries have made the HPV vaccines available for boys as well as girls. In the U.S., where two-thirds of U.S. teenagers and young adults say they have had oral sex, the shots are recommended for boys ages 11 and 12. More than 280,000 boys in Australia will be eligible for free doses of Merck’s Gardasil this year, estimated to prevent a quarter of new HPV infections, Health Minister Tanya Plibersek said in February.
“There’s also momentum for vaccination for boys as gay men can’t benefit from vaccination in girls,” said Szarewski, who has received honorary and consultancy fees from both Merck and London-based Glaxo. “It’s partly an equality issue.”
HPV vaccination hasn’t been recommended for boys in the U.K., according to Szarewski.
Rates of oral cancer are rising there, according to Hazel Nunn, head of health information at Cancer Research UK. While the most common causes are smoking and drinking, there is a link between the malignancies and HPV, she said in a statement.
In most cases, people infected with HPV have no symptoms and the virus goes away on its own, Nunn said. But sometimes the infection persists and leads to cancer. “There isn’t enough evidence to know how oral HPV infections are acquired or why, in some people, these infections go on to lead to oral cancer,” Nunn said. “For now, the best advice to cut the risk of oral cancer is to avoid tobacco and cut down on alcohol.”
Gardasil, sold by Merck of Whitehouse Station, New Jersey, protects against four strains of HPV: two that cause cancer, and two that cause genital warts. In the U.S., it’s approved for preventing cervical, vaginal and anal cancers as well as genital warts, and is recommended for girls and women ages 9 through 26. It’s also approved for preventing warts and anal cancer in boys and young men of the same ages. In Europe, the vaccine may be used for patients age 9 and older. Gardasil had sales of $1.6 billion last year.
Because Cervarix only protects against two strains of HPV that cause cancer, it’s approved in Europe and the U.S. for cancer prevention in girls and women, not for genital warts. Cervarix sales were 270 million pounds ($412 million) last year.
Like Gardasil, Cervarix isn’t specifically approved for preventing oral cancers. Studying the HPV vaccines for their impact on throat cancer would be very difficult as it’s such a rare type of malignancy, Szarewski said.
Glaxo, the U.K.’s biggest drugmaker, hasn’t been studying the vaccine as a way to prevent throat cancer, said David Daley, a company spokesman.
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