Cancer of the Cervix
The cervix is the lower part of the uterus (womb). The uterus has 2 parts. The upper part, called the body of the uterus, is where a baby grows. The cervix, in the lower part, connects the body of the uterus to the vagina, or birth canal.
Cancer of the cervix (also called cervical cancer) begins in the lining of the cervix. This cancer forms slowly. First, some cells begin to change from normal to pre-cancer and then to cancer. This can take many years, but sometimes it happens faster. These changes may be called dysplasia. They can be found by the Pap test and may need to be treated to prevent cancer. There are 2 main types of cancer of the cervix. About 8 to 9 out of 10 are squamous cell carcinomas. Under the microscope, this type of cancer is made up of cells that are like squamous cells that cover the surface of the cervix. Most of the rest are adenocarcinomas. These cancers start in the gland cells that make mucus. Less often, the cancer has features of both types and is called mixed carcinoma. Other types of cancer also can develop in the cervix, however, these are much more rare.
Risk Factors for Developing Cervical Cancer
For cervical cancer, the most important risk factor is infection with a virus known as HPV (human papilloma virus). HPV is really a group of more than 100 related viruses that can infect cells on the surface of the skin. Some types of HPV cause genital warts. Other types cause cancer of the cervix. The kinds that cause cancer are called "high-risk" HPVs. HPV is passed from one person to another by skin-to-skin contact such as vaginal, anal, or oral sex. But sex isn't the only way to spread HPV from one person to person. All that is needed is for there to be skin-to-skin contact with an area of the body infected with HPV.
Having unprotected sex, especially at a young age, makes HPV infection more likely. Also, women who have many sex partners (or who have sex with men who have had many partners) have a greater chance of getting HPV.
Many women may have HPV, but very few of these women will ever get cervical cancer. In most cases the body fights off the virus, and the infection goes away without any treatment. But in some women, the infection lasts and can cause cervical cancer. HPV is mainly found in young women and is less common in women over 30. We don't know why this is so. Condoms (rubbers) may help protect against HPV when they are used correctly. But HPV can still be passed from one person to another by skin-to-skin contact with an HPV-infected area of the body that is not covered by a condom. Still, it is important to use condoms because they can help protect against AIDS and other sexual diseases, too.
Even though HPV is an important risk factor for cervical cancer, most women with this infection do not get cervical cancer. Doctors believe other factors must come into play for this cancer to grow. Some of these factors are listed below.
Other risk factors include:
Smoking: Women who smoke are about twice as likely to get cervical cancer as those who don't. Smoking puts many chemicals that cause cancer into the lungs. These harmful substances are carried in the bloodstream throughout the body to other organs, too. Tobacco by-products have been found in the cervical mucus of women who smoke.
HIV infection: HIV (human immunodeficiency virus) is the virus that causes AIDS — it is not the same as HPV. It can also be a risk factor for cancer of the cervix. Having HIV seems to make a woman's immune system less able to fight both HPV and early cancers.
Chlamydia infection: This is a common kind of bacteria that can infect women's sex organs. It is spread during sex. A woman may not know that she is infected at all unless she is tested for chlamydia when she gets her pelvic exam. Some studies suggest that women who have a past or current infection are at greater risk for cancer of the cervix. Long-term infection can cause other serious problems, too.
Diet: What you eat can play a part as well. Diets low in fruits and vegetables are linked to an increased risk of cervical cancer. Also, women who are overweight are at a higher risk.
Birth control pills: Long-term use of birth control pills increases the risk of this cancer. Research suggests that the risk of cervical cancer goes up the longer a woman takes "the pill," but the risk goes back down again after she stops. You should talk to your doctor about the pros and cons of birth control pills in your case.
Having many pregnancies: Woman who have had 3 or more full-term pregnancies have an increased risk of this cancer. No one really knows why this is true.
Young age at the time of first full-term pregnancy: Women who were younger than 17 years when they had their first full-term pregnancy are almost 2 times more likely to get cervical cancer later in life than women who waited to get pregnant until they were 25 years or older.
Low income: Poor women are at greater risk for cancer of the cervix. This may be because they cannot afford good health care, such as regular Pap tests.
DES (diethylstilbestrol): DES is a hormone drug that was used between 1940 and 1971 for some women who were in danger of miscarriages. The daughters of women who took this drug while they were pregnant with them have a slightly higher risk of cancer of the vagina and cervix.
Family history: Cervical cancer may run in some families. If your mother or sister had cervical cancer, your chances of getting the disease are 2 to 3 times higher than if no one in the family had it. This could be because these women are less able to fight off HPV than other women.
Most cervical cancer can be prevented. There are 2 ways to prevent this disease. The first way is to find and treat pre-cancers before they become cancer, and the second is to prevent the pre-cancers.
A well-proven way to prevent cancer of the cervix is to have testing (screening) to find pre-cancers before they can turn into cancer. The Pap test (or Pap smear) is the most common way to do this. If a pre-cancer is found and treated, it can stop cervical cancer before it really starts. Most cervical cancers are found in women who have not had Pap tests when they should.
The American Cancer Society recommends the following:
- All women should begin having the Pap test about 3 years after they start having sex (vaginal intercourse), but no later than age 21.
- The test should be done every year if the regular Pap test is used, or every 2 years if the liquid-based Pap test is used.
- Beginning at age 30, many women who have had 3 normal test results in a row may get the Pap test every 2 to 3 years. Another option for women over 30 is to have a Pap test every 3 years plus the HPV DNA test.
- Women who have certain risk factors (like HIV infection or weak immune systems) should get a Pap test every year.
- Women 70 years of age or older who have had 3 or more normal Pap tests in a row (and no abnormal tests in the last 10 years) may choose to stop having the test. But women who have had cervical cancer or who have other risk factors (as mentioned above) should keep on having the test as long as they are in good health.
- Women who have had a total hysterectomy (removal of the uterus and cervix) may also choose to stop having the test unless the surgery was done as a treatment for cervical cancer or pre-cancer. Women who have had a simple hysterectomy (the cervix was not removed) should continue to follow the guidelines above.
Some women believe that they can stop having Pap tests once they have stopped having children. This is not correct. They should continue to follow American Cancer Society guidelines.
Many people confuse pelvic exams with Pap tests, perhaps because they are often done at the same time. The pelvic exam is part of a woman's regular health care. During this exam, the doctor looks at and feels the reproductive organs. Some women think that they do not need pelvic exams once they have stopped having children. This is not true.
The pelvic exam may help find diseases of the female organs. But it won't find cancer of the cervix at an early stage. To do that, the Pap test is needed. The Pap test is often done just before the pelvic exam. The doctor will remove cells from the cervix by gently brushing or scraping. The cells are sent to a lab to be looked at under a microscope.
Another means of prevention is getting an HPV vaccine. For more information on these, please see the HPV General Information section on this website, or visit the American Cancer Society at www.cancer.org.
(Information taken from American Cancer Society, www.cancer.org)