The cervix is the lower part of the uterus (womb). It is sometimes called the uterine cervix. The body of the uterus
(the upper part) is where a baby grows. The cervix connects the body of the uterus to the vagina (birth canal).
The part of the cervix closest to the body of the uterus is called the endocervix. The part next to the vagina is
the exocervix (or ectocervix). The 2 main types of cells covering the cervix are squamous cells (on the exocervix)
and glandular cells (on the endocervix). The place where these 2 cell types meet is called the transformation zone.
Most cervical cancers start in the transformation zone
Most cervical cancers begin in the cells lining the cervix. These cells do not suddenly change into cancer. Instead, the normal cells of the cervix first gradually develop pre-cancerous changes that turn into cancer. Doctors use several terms to describe these pre-cancerous changes, including cervical intraepithelial neoplasia (CIN), squamous intraepithelial lesion (SIL), and dysplasia. These changes can be detected by the Pap test and treated to prevent the development of cancer.
Cervical cancers and cervical pre-cancers are classified by how they look under a microscope. There are 2 main types of cervical cancers: squamous cell carcinoma and adenocarcinoma. About 80% to 90% of cervical cancers are squamous cell carcinomas. These cancers are from the squamous cells that cover the surface of the exocervix. Under the microscope, this type of cancer is made up of cells that are like squamous cells. Squamous cell carcinomas most often begin where the exocervix joins the endocervix.
Most of the other cervical cancers are adenocarcinomas. Cervical adenocarcinomas seem to have becoming more common in the past 20 to 30 years. Cervical adenocarcinoma develops from the mucus-producing gland cells of the endocervix. Less commonly, cervical cancers have features of both squamous cell carcinomas and adenocarcinomas. These are called adenosquamous carcinomas or mixed carcinomas.
Although cervical cancers start from cells with pre-cancerous changes (pre-cancers), only some of the women with pre-cancers of the cervix will develop cancer. The change from cervical pre-cancer to cervical cancer usually takes several years, but it can happen in less than a year. For most women, pre-cancerous cells will go away without any treatment. Still, in some women pre-cancers turn into true (invasive) cancers. Treating all pre-cancers can prevent almost all true cancers.
Pre-cancerous changes are separated into different categories based on how the cells of the cervix look under a microscope.
Although almost all cervical cancers are either squamous cell carcinomas or adenocarcinomas, other types of cancer also can develop in the cervix. These other types, such as melanoma, sarcoma, and lymphoma, occur more commonly in other parts of the body.
Can cervical cancer be prevented?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 find and treat pre-cancers before they become true cancers, and the second is to prevent the pre-cancers.
Things to do to prevent pre-cancers
Avoid being exposed to the human papilloma virus (HPV)Since HPV is the main cause of cervical cancer and pre-cancer, avoiding exposure to HPV could help you prevent this disease. HPV infections occur mainly in younger women and are less common in women older than 30. The reason for this is not clear. 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
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. Although the virus most often spreads between a man and a woman, HPV infection and cervical cancer are seen in women who have only had sex with other women. Remember that someone can have HPV for years and still have no symptoms -- it does not always cause warts or other problems. Someone can have the virus and pass it on without knowing it.
Still, since all that is required to pass HPV from one person to another is skin-to-skin contact with an area of the body infected with HPV, even never having sex doesn’t guarantee that you won’t ever get infected. It might be possible to prevent anal and genital HPV infection by never allowing another person to have contact with those areas of your body.
HPV and menFor men, the 2 main factors influencing the risk of genital HPV infection are circumcision and the number of sexual partners.
Men who are circumcised (have had the foreskin of the penis removed) have a lower chance of becoming and staying infected with HPV. Men who have not been circumcised are more likely to be infected with HPV and pass it on to their partners. The reasons for this are unclear. It may be that after circumcision the skin on the glans (of the penis) goes through changes that make it more resistant to HPV infection. Another theory is that the surface of the foreskin (which is removed by circumcision) is more easily infected by HPV. Still, circumcision does not completely protect against HPV infection -- men who are circumcised can still get HPV and pass it on to their partners.
The risk of being infected with HPV is also strongly linked to having many sexual partners (over a man's lifetime).
Condoms and HPVCondoms (" rubbers") provide some protection against HPV but they don't completely prevent infection. Men who use condoms are less likely to be infected with HPV and to pass it on to their female partners. One study found that when condoms are used correctly every time sex occurs they can lower the HPV infection rate by about 70%. One reason that condoms cannot protect completely is 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. Condoms (when used by the male partner) also seem to help the HPV infection and cervical pre-cancers go away faster.
Don’t smokeNot smoking is another important way to reduce the risk of cervical pre-cancer and cancer.
Get vaccinatedVaccines 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 and approved for use. Both vaccines require a series of 3 injections over a 6-month period.
Side effects are usually mild. The most common one is short-term redness, swelling, and soreness at the injection site. Rarely, a young woman will faint shortly after the vaccine injection.