New Vaccine the Latest Weapon in the Fight against Cervical Cancer

David Boruta, M.D., Gynecologic Oncology, Columbia St. Mary’s

Posted: Jan. 1, 2007

Most people would not place the flu, chicken pox and cervical cancer in the same category, but now these three diseases have something in common. Last fall a new FDA-approved vaccine became available which effectively prevents infection by human papilloma virus (HPV) – the root cause of nearly all cervical cancer cases world-wide.

There are approximately 100 different recognized types of HPV. While around 30 have been found to be associated with the development of cervical cancer, and other genital cancers such as vulvar and vaginal cancers, two specific viral types, Types 16 and 18, account for over 70% of the cases of cervical cancer in the United States. The new FDA-approved vaccine immunizes women against infection by these two viral types, as well as by HPV Types 6 and 11 that cause around 90% of genital warts.

The vaccine is made with “virus like particles” that are derived from the substance that makes up the outer surface of HPV. Although the “virus like particles” cannot cause real HPV infection, the body can develop antibodies against them. When the vaccinated person is exposed to real HPV of the same type, the immune system is more capable of fighting the infection.

The current vaccine, Gardasil, has been approved for women ages 9 to 26 and is recommended regardless of whether women have or previously had an abnormal Pap test, a positive HPV test, or genital warts. The vaccine is typically given by primary care physicians and is dispensed in three doses: one right away, a second dose two months later and the final dose four months after that. The vaccine is only effective at preventing infection. The vaccine is not a treatment for HPV infection or abnormal Pap tests. Therefore, it is ideally given prior to the initiation of any behaviors that expose women to HPV, namely sexual activity.

Currently, nearly 80% of all women will at some point in their life have an infection with HPV, including the types that can cause cervical cancer. Fortunately, most infections are transient and result in no significant health problem. But in a small percentage of women, the infection persists for years, often without symptoms, and the risk of cervical cancer rises. The incidence of HPV infection is highest for women in their 20s, and drops significantly after the age of 30, but can be contracted by anyone who is sexually active.

In a series of very large studies, the vaccine was between 95% and 100% effective in preventing the development of severe cervical pre-cancers related to infection with HPV Types 6, 11, 16, and 18. It was also 99% effective in preventing the development of genital warts related to these viral types. It appears that protection continues for many years, although ongoing studies will determine whether boosters will be necessary to maintain prolonged protection. Few side effects occurred in the studies, primarily irritation at the injection site (given in the arm).

Although these results are impressive, it is important to reinforce the fact that multiple other HPV types (besides those which the current vaccine targets) have been associated with the development of cervical cancer, comprising up to 30% of cases. Sexual activity and other behaviors that result in exposure to HPV, regardless of vaccination status, can increase the risk of developing health problems associated with HPV, such as cervical cancer, not to mention other sexually transmitted diseases.

Even after vaccination, regular physician checkups, including Pap tests, are necessary and continue to be recommended. Regular Pap smear testing has decreased the prevalence of cervical cancer by 7% in developed countries like the United States. Because there are very few physical symptoms of early cervical cancer, an abnormal Pap smear is usually the only way to detect if a woman is at risk of developing cervical cancer. For the time being, Pap testing will continue to be a part of the standard of care in protecting women from cervical cancer.

After prevention of HPV infection in the first place, detection and treatment of significant cervical abnormalities on a Pap test is the best way to avoid cervical cancer. Believe it or not, nearly half of all the women diagnosed with cervical cancer in the United States have NEVER had a Pap test, and another 10% haven’t had a Pap test within the past five years. Women should begin to have Pap tests either three years after the onset of sexual activity, or at the age of 21, whichever comes first. The interval between Pap tests should be determined individually with your physician.

Through preventing HPV infection and through early detection of precancerous cells using the Pap test, we can help most women avoid this disease all together.

Women who develop cervical cancer can be cured, especially if it’s detected early. Surgical removal of the tumor, destruction of the tumor with radiation and/or chemotherapy, or some combination treatment is most often utilized. Procedures are also being explored that effectively treat smaller cervical cancers while attempting to preserve a woman’s ability to complete a pregnancy following treatment of her cervical cancer. Ideally though, prevention of the cancer in the first place, both with the help of an effective vaccine which we now appear to have, and with effective screening for precancers using tests like the Pap smear, is simpler, safer and more desirable.

David Boruta, M.D.
Gynecologic Oncology
Columbia St. Mary’s
(414) 326-1745

We Have Answers
Do you have medical questions or need help finding a doctor? The experts at Columbia St.Mary’s can help. Click here.