TAMPA — Actor Michael Douglas created a stir over the weekend when he suggested in an interview that his throat cancer was most likely caused by oral sex.
Through a publicist, he later appeared to backpedal from the statement, but the connection came as no surprise to medical experts. Human papilloma virus, or HPV, is a sexually transmitted virus perhaps most commonly associated with cervical cancer. However, it also causes about 70 percent of cancers of the tonsils and the base of the tongue.
HPV is the most common sexually transmitted infection — most people get it at some point in life — and often there are no symptoms. The virus usually goes away before it causes serious damage, but not everyone is so fortunate. HPV-related cancers are on the increase.
To find out more about HPV and Douglas' statement, we turned to Anna Giuliano, a researcher and director of the Center for Infection Research in Cancer at Moffitt Cancer Center in Tampa. Giuliano was involved in early testing of the HPV vaccine that now is widely recommended for girls and boys.
Why is HPV a threat?
Because it's a very common infection that will cause cancer in a minority of infected people. The problem is we don't know who will develop cancer. That's why prevention is so important. HPV vaccination is one of those prevention measures we can take to stop the spread of a potentially serious infection. The vaccine has not been proven to prevent oropharyngeal cancer (cancers of the base of the tongue and the tonsils), but we know it can prevent genital and anal infections and cancers.
What do we know about HPV and cancer?
Of all the oropharyngeal cancers, 70 percent of those at the base of the tongue and in the tonsils have HPV in the tumors, mainly HPV 16. That subset of cancers at the base of the tongue and in the tonsils is more likely caused by HPV than by smoking and alcohol. It has been published that Michael Douglas' cancer tested positive for HPV. The good news is that HPV-related cancers have better survival than if the tumors are caused by smoking and drinking. The other good news is that cancers of the head and neck related to smoking are declining, our strong tobacco use prevention policies are working, but HPV related cancers are on the rise.
How is HPV spread?
It's a sexually transmitted disease, and oral sex is one way in which you can acquire HPV, but it's not the only way. The infection can be transmitted skin to skin during a sexual encounter, by touching. But it's not transmitted by toilet seats and counter tops. Moffitt is currently studying how HPV is transmitted because we need to know more about how people become infected.
How do you know if you have HPV?
The type that causes cancer, HPV 16, has no visible signs and no symptoms. With the type that causes genital or anal warts, you see a wart or growth which may also be found in the mouth. But that kind doesn't cause cancer. Women who are infected may have abnormal cells which appear on the cervix and which … are collected during a routine Pap test and checked for HPV. Women can then be treated early before cancer develops.
What about testing men?
Without a screening test like the one we have for women, the cells in men will continue to multiply and travel to the lymph nodes, so they may have swelling in the neck. For that reason, cancer is generally diagnosed in men as a late stage metastatic tumor. That's why we desperately need more research to find out how to screen men for this cancer.
What's the likelihood of giving HPV to a sexual partner?
We don't know. The good news for women is we can screen them and treat them before it becomes cancer. But men have nothing like this. That's why vaccinating adolescent boys is important — it will protect them against HPV infection.
Does the vaccine protect against all kinds of HPV?
There are over 100 kinds of HPV. HPV 16 and 18 cause cancer in men, similar to women. Both vaccines on the market in the U.S. today protect against those two types of HPV infection.
What do you think of Michael Douglas' statement?
I wish he had talked about his treatment because treatment (for this cancer) is miserable. They focus direct radiation at the throat. … Patients can't swallow. They have tremendous weight loss. It's a horrible experience. If we could prevent that, we'd be making big strides.
Contact Irene Maher at email@example.com.