July 17, 2009

Cervical Cancer - Causes and Preventive Measures


In recent years, scientists have made much progress toward understanding what happens in cells of the cervix when cancer develops. In addition, they have identified several risk factors that increase the odds that a woman might develop cervical cancer.

The development of normal human cells mostly depends on the information contained in the cells’ chromosomes. Chromosomes are large molecules of DNA. DNA is the chemical that carries the instructions for nearly everything our cells do. We usually resemble our parents because they are the source of our DNA. However, DNA affects more than our outward appearance.

Some genes (packets of our DNA) have instructions for controlling when our cells grow and divide. Certain genes that promote cell division are called oncogenes. Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA mutations (gene defects) that turn on oncogenes or turn off tumor suppressor genes. Scientists now think that HPV causes the production of 2 proteins known as E6 and E7. When these proteins are produced, they turn off some tumor suppressor genes. This may allow the cervical lining cells to grow uncontrollably, which in some cases will lead to cancer.

But HPV does not completely explain what causes cervical cancer. Most women with HPV don’t get cervical cancer, and certain other risk factors, like smoking and HIV infection, influence which women exposed to HPV are more likely to develop cervical cancer


Since the most common form of cervical cancer starts with pre-cancerous changes, there are 2 ways to stop this disease from developing. The first way is to prevent the pre-cancers, and the second is to find and treat pre-cancers before they become cancerous.

Things to do to prevent pre-cancers

Avoid being exposed to HPV:You can prevent most pre-cancers of the cervix by avoiding exposure to HPV. Certain types of sexual behavior increase a woman's risk of getting HPV infection, such as:

having sex at an early age
having many sexual partners
having a partner who has had many sex partners
having sex with uncircumcised males

Delay sex: Waiting to have sex until you are older can help you avoid HPV. It also helps to limit your number of sexual partners and to avoid having sex with someone who has had many other sexual partners. Remember that someone can have HPV for years yet have no symptoms - it does not always cause warts or any other symptoms. Someone can have the virus and pass it on without knowing it.

Use condoms: Condoms provide some protection against HPV. One study found that when condoms are used correctly they can lower the HPV infection rate by about 70% - if they are used every time sex occurs. Condoms cannot protect completely because they don't cover every possible HPV-infected area of the body, such as skin of the genital or anal area. Still, condoms provide some protection against HPV, and they also protect against HIV and some other sexually transmitted diseases.

Don’t smoke: Not smoking is another important way to reduce the risk of cervical precancer and cancer.

Get vaccinated: Vaccines have been developed that can protect women from HPV infections. So far, a vaccine that protects against HPV types 6, 11, 16 and 18 (Gardasil®) and one that protects against types 16 and 18 (Cervarix®) have been studied.

Gardasil® has been approved for use in this country by the FDA. It requires a series of 3 injections over a 6-month period. The second injection is given 2 months after the first one, and the third is given 4 months after the second. Side effects are said to be mild. The most common one is short-term redness, swelling, and soreness at the injection site. In clinical trials, Gardasil prevented genital warts caused by HPV types 6 and 11 and prevented pre-cancers and cancers of the cervix caused by HPV types 16 and 18. This vaccine only works to prevent HPV infection -- it will not treat an infection that is already there.

To be most effective, the HPV vaccine should be given before a person starts having sex. The Federal Advisory Committee on Immunization Practices (ACIP) has recommended that the vaccine be given routinely to females aged 11 to 12. It can be given to younger females (as young as age 9) at the discretion of doctors. ACIP also recommended women ages 13 to 26 who have not yet been vaccinated get "catch-up" vaccinations.

The American Cancer Society also recommends that the vaccine be routinely given to females aged 11 to 12 and as early as age 9 years at the discretion of doctors. The Society also agrees that “catch-up” vaccinations should be given to females aged 13 to 18. The independent panel making the Society recommendations found that there was not enough proof of benefit to recommend catch-up vaccination for every woman aged 19 to 26 years. As a result, the American Cancer Society recommends that women aged 19 to 26 talk with their health care provider about the risk of previous HPV exposure and potential benefit from vaccination before deciding to get vaccinated. Research is now being done on using Gardasil in older women and in males. The American Cancer Society guideline focuses on Gardasil at this time. As new information on Cervarix®, Gardasil®, and other new products becomes available, these guidelines will be updated.

Gardasil is expensive - the vaccine series costs around $360 (not including any doctor’s fee or the cost of giving the injections). It should be covered by most medical insurance plans (if given according to ACIP guidelines). It should also be covered by government programs that pay for vaccinations in children under 18. Because this vaccine costs so much, you may want to check your coverage with your insurance company first.

It is important to realize that the vaccine doesn’t protect against all cancer-causing types of HPV, so routine Pap tests are still necessary. One other benefit of the vaccine is that it protects against the 2 viruses that cause 90% of genital warts.

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