Cervical cancer is the second most common cancer in women worldwide. In the US, more than 10,000 cases of cervical cancer were diagnosed in 2004, and almost 4,000 women died from the disease. Over the past 50 years however, there has been a 75% decrease in the occurrence of and death from cervical cancer in developed nations. Screening using the Pap test is largely responsible for this decrease.

Unlike vitrtually all other cancers, the main cause of cervical cancer is known. Persistent infection with the human papillomavirus (HPV) is the culprit. Discovery of this link has led to the development of an HPV vaccine, which targets HPV16 and HPV18, the two most common cancer-causing strains. Studies conducted with this vaccine have found that it can prevent at least 90% of HPV infections and their associated precursors of cervical cancer.

A study published online in the April 6, 2006 issue of the Lancet was a follow-up to a study that previously looked at an HPV vaccine. The initial study was conducted in 2004 and found that the vaccine was effective in preventing cervical cancer. This follow-up study evaluated the long-term efficacy and safety of the vaccine.

About the Study

The follow-up study included more than 700 women from the initial study. These women originally received three doses of the vaccine or placebo and were followed for up to 27 months. The follow-up for this study continued for an average of 48 months.

The researchers found that the women who received the vaccine had high levels of HPV antibodies against both HPV16 and HPV18 for up to 4.5 years after receiving their last dose. The vaccine provided a high degree of protection against infection throughout the follow-up period. Due to the strong relationship between cervical cancer and HPV infection, the vaccine may lead to the long-term prevention of HPV16- and HPV18-associated cancers. The study also found a high degree of protection against HPV31 and HPV45, the third and fourth most common cancer-causing strains.

In addition, more women in the placebo group than the vaccine group reported adverse events, leading the researchers to determine that the vaccine had a good long-term safety profile.

How Does This Affect You?

Cervical cancer is unique in that it is one of the only cancers for which a single major cause has been identified. Wide-scale adoption of the HPV vaccine appears to make good sense for the prevention of cervical cancer, especially in less developed countries where screening isn’t readily available on a wide scale. If successful, the vaccine could eventually make frequent Pap smears obsolete in certain populations of women. .

However, the vaccine is not without its controversy. HPV is a sexually transmitted disease, and some feel that a vaccination program may increase risky sexual behavior, especially among younger women. The vaccine is not FDA approved yet. When and if it is, there will likely be debate on who should receive it and at what age. If you are interested in the vaccine, talk with your doctor about the pros and cons of vaccination should it become available.