Today, we welcome a guest blog from the American Cancer Society's director of breast and gynecologic cancer, Debbie Saslow, PhD, providing an overview of the human papillomavirus (HPV) vaccine for cervical cancer prevention.
Many people ask me about whether or not their daughters should get the human papillomavirus (HPV) vaccine, which can help prevent cervical cancer. As with all new vaccines, there has been some controversy. Some parents have been reluctant to get their daughters vaccinated before they are sexually active, yet this is precisely when the vaccine will be most effective. Others were concerned about safety; the HPV vaccines are extremely safe, based on tens of millions of doses distributed worldwide. There was also an initial push, generated by the manufacturer, to require HPV vaccination for middle school enrollment. To date only Virginia and Washington, D.C., have such a requirement.
To answer the question of whether to vaccinate, it helps to have some background:
In the United States, an estimated 12,200 cases of invasive cervical cancer were expected to be diagnosed in 2010, with an estimated 4,210 deaths. But there have been fewer deaths over the past several decades due to cancer screening tests. That's great news. But we can reduce the number of people even getting cervical cancer by doing what we know works.
Virtually all cervical cancers are caused by HPV. There are more than 100 types of HPV, of which a few dozen can infect the genital tract and about 15 can cause cancer of the cervix. The types of HPV that cause cervical cancer are transmitted by genital skin-to-skin contact, almost always during sex. Infections are usually temporary, with the body's immune system fighting off the infection before there are any symptoms. In some cases, the infection doesn't go away, and the virus may cause cells in the cervix to become pre-cancerous. These pre-cancerous cells in turn usually go back to normal on their own, but sometimes they turn into cancer if they are not found and removed or treated.
What a lot of people don't realize is that most cervical cancer can be prevented. There are two ways to prevent this disease:
The first way is to find and treat pre-cancers before they become cancer. The Pap test (or Pap smear) is the most common way to find pre-cancers before they can turn into cancer. In fact, most cervical cancers are diagnosed in women who have never had a Pap test, or who haven't had one in the last five years. HPV tests to find out if you have an HPV infection that could cause cervical cancer are also available and a very helpful tool in the prevention of cervical cancer and pre-cancers. When a HPV test comes back positive, it lets the health care professional know that a woman is at higher risk for cervical pre-cancers.
Then there's the second way of preventing cervical cancer: getting vaccinated against the two types of HPV that cause 70% of all cervical cancers. There are two vaccines available for this purpose in the United States, Gardasil and Cervarix.
To be most effective, the HPV vaccine should be given before a girl has any type of sexual contact with another person. (The vaccines will not prevent HPV in people who have already had these HPV types.) The American Cancer Society and others recommend that the vaccine be given to girls at age 11 to 12.
The vaccine can also be given to girls as young as age 9, and to girls ages 13 to 18 who have not been vaccinated. Some groups also recommend vaccination of women ages 19 to 26, but the American Cancer Society believes that there is not enough evidence of benefit to recommend vaccinating all women in this age group. We do recommend that women ages 19 to 26 talk to their health care professionals about whether or not to get the vaccine by weighing their risk of previous HPV exposure with the potential benefit from the vaccine
HPV vaccines are not approved nor recommended for girls younger than 9 or for women older than age 26.
It is important to get all 3 doses of the vaccine. Even if she's been vaccinated, though, a girl will still need to get regular Pap tests when she is old enough because the vaccines do not protect against all types of cancer-causing HPV.
We at the American Cancer Society have been actively involved in providing credible and unbiased information to the public and to health care providers about the HPV vaccine. We also emphasize the ongoing need to follow screening guidelines, such as getting regular Pap tests, and the critical need to ensure that the vaccines are available to those who are medically underserved.
And as an important sidenote: HPV vaccines also help prevent cancers of the vulva (the outer part of the female genitals) and the vagina (the birth canal), related to the two types of HPV in the vaccines. And in late December 2010 Gardasil was approved for the prevention of anal cancers in both men and women. [Editor's note, added 1/5/12: In October 2011 the Advisory Committee on Immunization Practices recommended that boys as well as girls be vaccinated against HPV.] It is possible that the vaccines also could prevent some other HPV-related cancers, including some head and neck cancers. However, it will be years or even decades before studies can prove whether or not they will prevent these cancers.
For more information about cervical cancer, click here.
To see our full recommendation on HPV vaccines, click here.
To see some FAQs about HPV, the vaccines, and cervical cancer, click here.
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