Cervical Cancer: A New Vaccine and a Brighter Future

By Levi Downs, M.D.
(October 20, 2006)

Some women may only become aware of cervical cancer when they get the results of their Pap smear. But, worldwide, cervical cancer is the second most common cancer in women, and it causes an estimated 233,000 deaths each year. Virtually all these cancers are caused by the human papillomavirus (HPV), which is spread through sexual contact.

A new vaccine called Gardasil, recently approved by the FDA, holds the promise of changing this scenario.  The vaccine can prevent the HPV infections that cause 70 percent of cervical cancers.  And other new drugs being tested at the University of Minnesota may further lower rates of cervical cancer.

Each year in the United States, about 6.2 million people become infected with HPV, making it the most common sexually transmitted infection. The virus can spread through any kind of genital contact, and, once a woman is infected, it’s possible for certain types of HPV to cause cells in the cervix, the lower  part of the uterus that opens into the vagina, to become abnormal, a condition known as cervical dysplasia. A Pap smear tests for these abnormal cells. Usually, the abnormal cells return to normal, but in some women they progress to become cervical cancer.

Until recently, the only way to lower the risk of getting HPV was to avoid behaviors that could result in exposure to the virus, such as:

• sex at an early age
• multiple sex partners
• a sex partner who has had many partners

We believe that condom use lowers the risk of HPV infection, but cannot prevent it since skin-to-skin contact can result in exposure to the virus.

The vaccine Gardasil immunizes women against the types of HPV that cause 70 percent of all cervical cancers.  To be effective, this vaccine must be given before a woman is infected with the targeted HPV strains. For this reason, the Centers for Disease Control recommends routine vaccination for girls ages 11 to 12, before sexual activity may begin. The vaccination is given as three injections over a six-month period; it should be covered by most insurance plans. Gardasil is licensed for use in females aged nine through 26. Because we don't know yet if the vaccine continues to protect after the first five years, research is ongoing to learn if a booster shot is needed.

Gardasil will not protect women who are already infected with the HPV types targeted by the vaccine.  For these women, clinical trials are underway at the University of Minnesota to evaluate a drug that treats abnormal cervical cells.  The drug being tested causes the body’s immune system to attack and eliminate abnormal cervical cells. With early results looking successful, we expect to submit data within two years to the FDA for approval.

A vaccine that immunizes against the same cancer-causing strains of HPV as Gardasil, called Cervarix, was recently tested at the University of Minnesota as part of worldwide clinical trials and will be available in mid-2007. Research on Cervarix continues elsewhere to produce a lower-cost powdered form for use in developing nations where refrigeration is often not available.

Because Gardasil does not protect against the HPV types that cause the remaining 30 percent of cancers, we are also preparing to test a next-generation version. This version of the vaccine would protect against eight types of HPV.  Clinical trials will begin at University of Minnesota in early 2007.

NOTE:  Levi Downs, M.D., is a faculty member in the Department of Obstetrics and Gynecology and a Cancer Center Clinical Scholar at the University of Minnesota.      

This column is an educational service of the University of Minnesota.  Advice presented should not take the place of an examination by a health-care professional. For more health-related information, go to http://www.healthtalk.umn.edu.