Cervical Cancer Prevention (PDQ®)
Last modified: 2015-10-23
Last downloaded: 2016-01-22
What is prevention?
Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.
To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.
Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.
Different ways to prevent cancer are being studied, including:
- Changing lifestyle or eating habits.
- Avoiding things known to cause cancer.
- Taking medicines to treat a precancerouscondition or to keep cancer from starting.
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General Information About Cervical Cancer
Cervical cancer is a disease in which malignant (cancer) cells form in the cervix. The cervix is the lower, narrow end of the uterus (the hollow, pear-shaped organ where a fetus grows). The cervix connects the uterus to the vagina (birth canal).Anatomy of the female reproductive system. The organs in the female reproductive system include the uterus, ovaries, fallopian tubes, cervix, and vagina. The uterus has a muscular outer layer called the myometrium and an inner lining called the endometrium.
Cervical cancer usually develops slowly over time. Before cancer appears in the cervix, the cells of the cervix go through a series of changes in which cells that are not normal begin to appear in the cervicaltissue. When cells change from being normal cells to abnormal cells, it is called dysplasia. Depending on the number of abnormal cells, dysplasia may go away without treatment. The more abnormal cells there are, the less likely they are to go away. Over time, dysplasia that is not treated may turn into cancer. The cancer cells grow and spread through the cervix. It can take many years for dysplasia to turn into cancer.
See the following PDQ summaries for more information about cervical cancer:
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Cervical Cancer Prevention
- Avoiding risk factors and increasing protective factors may help prevent cancer.
- The following are risk factors for cervical cancer:
- The following protective factors decrease the risk of cervical cancer:
- Cancer prevention clinical trials are used to study ways to prevent cancer.
- New ways to prevent cervical cancer are being studied in clinical trials.
Avoiding risk factors and increasing protective factors may help prevent cancer.
Avoiding cancerrisk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.
The following are risk factors for cervical cancer:
Infection with human papillomavirus (HPV) is the most common cause of cervical cancer. HPV infections that cause cervical cancer are spread through sexual contact. There are more than 80 types of human papillomavirus and about 30 of these can infect the cervix. HPV types 16 and 18 are most often linked to cervical cancer.
Most of the time, the body’s immune system can fight the HPV infection. Only a very small number of women infected with HPV develop cervical cancer.
Having a weakened immune system caused by immunosuppression increases the risk of HPV infection and cervical cancer. Immunosuppression is a condition in which the body's immune system is weakened and its ability to fight infections and other diseases is lessened. Long-term immunosuppression may increase the risk of cervical cancer because it lowers the body's ability to fight HPV infection.
Immunosuppression can be caused by the following:
- Human immunodeficiency virus (HIV). This virus causes AIDS and weakens the body's immune system. Women who are infected with the HIV virus have an increased risk of HPV infection and cervical cancer compared with women who are not infected with HIV.
- Medicine to prevent organ rejection after transplant. Women who have an organ transplant are given medicine to weaken the body’s immune system and help prevent organ rejection.
Being exposed to a drug called diethylstilbestrol (DES) while in the mother's womb increases the risk of cervical dysplasia and clear cell adenocarcinoma of the vagina and cervix. Between 1940 and 1971, DES was given to some pregnant women in the United States to prevent miscarriage (premature birth of a fetus that cannot survive) and premature labor.
In women with HPV infection, other risk factors are also associated with an increased risk of cervical cancer.
Among women who are infected with HPV, those who have had 7 or more full-term pregnancies have an increased risk of cervical cancer.
Among women who are infected with HPV, those who have used oral contraceptives ("the Pill") for 5 to 9 years have a risk of cervical cancer that is 3 times greater than that of women who have never used oral contraceptives. The risk is 4 times greater after 10 or more years of use. In women who stop taking oral contraceptives, over a 10 year period, the risk of cervical cancer returns to that of women who never used oral contraceptives.
Women who either smoke cigarettes or breathe in secondhand smoke have an increased risk of cervical cancer. The risk increases with the number of cigarettes smoked per day and how long the woman has smoked. Among women infected with HPV, current and former smokers have 2 to 3 times the risk of cervical dysplasia and invasive cervical cancer.
The following protective factors decrease the risk of cervical cancer:
Almost all cases of cervical cancer are caused by HPV infection, which is spread through sexual activity. Cervical cancer is seen more often in women who are sexually active at an early age and who have multiple sexual partners.
Vaccines that protect against HPV infection greatly reduce the risk of cervical cancer. These vaccines do not protect women who are already infected with HPV.
Several HPV vaccines have been approved by the U.S. Food and Drug Administration (FDA). These vaccines have been shown to prevent infection with the types of HPV that cause most cervical cancers. Protection against HPV infection lasts for 6 to 8 years. It is not known if the protection lasts longer.
Some methods used to prevent sexually transmitted diseases (STDs) decrease the risk of HPV infection. The use of a barrier method of birth control, such as a condom or diaphragm, helps protect against HPV infection.
Cancer prevention clinical trials are used to study ways to prevent cancer.
Cancer preventionclinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.
The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.
New ways to prevent cervical cancer are being studied in clinical trials.
Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI website. Check NCI's list of cancer clinical trials for cervical cancer prevention trials that are now accepting patients.
Back to Top Source: The National Cancer Institute's Physician Data Query (PDQ®) Cancer Information Summaries (http://www.cancer.gov/cancertopics/pdq)