Who could have imagined that a three-letter virus – HPV — could generate so much confusion and controversy?
Oh, wait, there is precedence for all the political posturing, fear and mis-information about HPV, the human papillomavirus, one of the most common sexually transmitted infections. We saw the same take place around HIV, a far more deadly virus and one that continues to wreak havoc and claims thousands of lives a year. And it took decades of advocacy, much of which is still ongoing, to bring attention to the need to stop HIV in its tracks, before it leads to AIDS. That same advocacy and public health campaigning is now underway to help consumers better understand HPV and what people can do about it, and how important it is for young people to receive vaccines that can protect them from infection with the virus.
Researchers have identified more than 40 types of HPV, a very common virus that the human body normally sheds on its own. Two types – HPV 16 and HPV 18 — are of special concern in the cancer community, though, because, undetected and untreated, they lead to most cases of cervical cancer. Now one of them, HPV16, is proving to be the cause of most new cases of throat cancers that develop at the base of the tongue and tonsils.
Routine pap tests and annual gynecological exams have lowered cervical cancer incidence in the United States, but cervical cancer is still one of the leading cancer killers of women worldwide. Thus, great research emphasis was placed on finding a vaccine to prevent infection with HPV 16 and 18 in the first place. Now there are two such HPV vaccines licensed by the FDA to prevent the spread of HPV and thus to prevent cervical cancer.
While screening with the Pap test has long proven an effective way to help prevent cervical cancer in developed countries, screening for HPV 16 infection for throat or other kinds of cancer would be fruitless. While 20 million Americans are estimated to be living with HPV 16 in their systems, 90% of those people will clear the virus on their own. A big concern with HPV 16 and throat cancer is that doctors do not yet understand why the virus becomes cancer in some.
Because the virus is so widespread yet causes cancer in a relatively small percentage of cases of infection, screening for it does not make sense, explains Dr. Shin, a leading head and neck cancer specialist at Winship Cancer Institute of Emory University. The most important unanswered question about HPV16 and throat cancer is why does it develop into cancer in some people but not in the majority of people.
“How does this virus get into a host cell and then go into carcinogenesis? This is what we would like to address,” explains Dr. Dong Moon Shin. Winship researchers such as Shin are aggressively looking for answers.
Much of the confusion and political hoopla about HPV have stemmed from misinformation about the vaccine, which is unfortunate. The vaccine is safe. It is effective. Because of the rising incidence of oropharyngeal cancer, it is now advised that both girls and boys also receive the vaccine, which is given in a series of three shots. To be effective, the shots must be given before a girl or boy becomes sexually active and is not administered to females after they hit age 26. Some of the concern about the vaccine is that parents don’t like the idea of giving children another round of vaccines, but the HPV vaccines have been approved by the FDA after rigorous clinical trials. They work.
HPV facts & stats:
- More than 40 types of HPV have been identified by researchers.
- More than 20 million adult Americans are believed to be living with the HPV 16 virus.
- In 90 percent of cases, the body’s immune system clears HPV within two years.
Prognosis for cases of HPV16-caused throat cancer is good, so long as the patient is a non-smoker. Winship researchers and others are looking for ways to identify whether patients with HPV16-caused throat cancer need as much treatment as patients whose cancer is not caused by the virus.
Dr. Peter Rossi and Dr. Namita Khanna just hosted an online chat on the topic of HPV and cervical cancer. For their thoughts, check out the HPV / Cervical Cancer chat transcript.