We believe in the power of early detection. Since the introduction of the Pap test in the 1950s, the number of yearly deaths from cervical cancer has dropped from 35,000 to less than 4,000 today. We hope to take this number even lower by continuing research on HPV and its various strains; by educating women about the importance of regular cervical screening; and by educating parents and young people about the HPV vaccine.
A number of factors may increase the risk of cervical cancer. The primary cause is infection with HPV (human papillomavirus), a group of viruses that can infect the cervix. These viruses are very common and are passed from person to person through sexual contact. There is no cure for HPV, just as there is no cure for the common cold. Most adults have been infected with HPV at some time in their lives, but most infections clear up on their own.
When the infection doesn't go away, it can cause cervical cancer in some women by altering the cells in the cervix. If these abnormal cells are found early, cervical cancer can be prevented by removing or killing the cells before they can develop into cancer.
Other risk factors that may act together with HPV to increase the risk even further include:
- Lack of regular Pap tests: Cervical cancer is more common among women who don't have regular Pap tests. In fact, 60 to 80 percent of women diagnosed with invasive cervical cancer have not had a pap smear in the past five years. The Pap test helps doctors find abnormal cells. Removing or killing the abnormal cells usually prevents cervical cancer.
- Smoking: Among women who are infected with HPV, smoking cigarettes slightly increases the risk of cervical cancer.
- Weakened immune system: Infection with HIV (the virus that causes AIDS) or taking drugs that suppress the immune system increases the risk of cervical cancer.
- Sexual history: Women who have had many sexual partners have a higher risk of developing cervical cancer. Also, a woman who has had sex with a man who has had many sexual partners may be at higher risk of developing cervical cancer. In both cases, the risk of developing cervical cancer is higher because these women have a higher risk of HPV infection.
- Using birth control pills for a long time: Using birth control pills for a long time (five or more years) may slightly increase the risk of cervical cancer among women with HPV infection. However, the risk decreases quickly when women stop using birth control pills.
- Having many children: Studies suggest that giving birth to many children (five or more) may slightly increase the risk of cervical cancer among women with HPV infection.
- DES (diethylstilbestrol): DES may increase the risk of a rare form of cervical cancer in daughters exposed to this drug before birth. DES was given to some pregnant women in the United States between about 1940 and 1971. (It is no longer given to pregnant women.)
Having an HPV infection or other risk factors does not mean that a woman will develop cervical cancer. Most women who have risk factors for cervical cancer never develop it.
The HPV vaccine is highly effective in preventing HPV infection, the major cause of cervical cancer. The vaccine protects against four types of HPV, including two that cause about 70 percent of cervical cancers, and is effective in reducing the risk of cervical pre-cancers.
About 30 percent of cervical cancers will not be prevented by these vaccines. Because the vaccines do not protect against all HPV infections that cause cervical cancer, it is important for vaccinated women to continue to undergo cervical cancer screening.
- Gardasil®: protects against four HPV types (6, 11, 16, and 18). Gardasil is given through a series of three injections into muscle tissue over a six-month period. The FDA has approved Gardasil for use in females for the prevention of cervical cancer, and some vulvar and vaginal cancers, caused by HPV types 16 and 18, and for use in males and females for the prevention of anal cancer and precancerous anal lesions caused by HPV types 16 and 18. Gardasil is also approved for the prevention of genital warts caused by HPV types 6 and 11. The vaccine is approved for these uses in females and males ages nine to 26.
- Cervarix®: targets two HPV types (16 and 18). This vaccine is also given in three doses over a six-month period. The FDA has approved Cervarix for use in females ages nine to 25 for the prevention of cervical cancer caused by HPV types 16 and 18.