The cervix is part of a woman's reproductive system. It's in the pelvis. The cervix is the lower, narrow part of the uterus (womb).
The cervix is a passageway:
- The cervix connects the uterus to the vagina. During a menstrual period, blood flows from the uterus through the cervix into the vagina. The vagina leads to the outside of the body.
- The cervix makes mucus. During sex, mucus helps sperm move from the vagina through the cervix into the uterus.
- During pregnancy, the cervix is tightly closed to help keep the baby inside the uterus. During childbirth, the cervix opens to allow the baby to pass through the vagina.
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.
Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.
Tumors can be benign or malignant:
Growths on the cervix can be benign or malignant. Benign growths are not cancer. They are not as harmful as malignant growths (cancer).
- Benign growths (polyps, cysts, or genital warts):
- are rarely a threat to life
- don't invade the tissues around them
- Malignant growths (cervical cancer):
- may sometimes be a threat to life
- can invade nearby tissues and organs
- can spread to other parts of the body
Cervical cancer begins in cells on the surface of the cervix. Over time, the cervical cancer can invade more deeply into the cervix and nearby tissues.
Cervical cancer cells can spread by breaking away from the cervical tumor. They can travel through lymph vessels to nearby lymph nodes. Also, cancer cells can spread through the blood vessels to the lungs, liver, or bones.
After spreading, cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues.
When you get a diagnosis of cancer, it's natural to wonder what may have caused the disease. Doctors cannot always explain why one woman develops cervical cancer and another does not. However, we do know that a woman with certain risk factors may be more likely than others to develop cervical cancer. A risk factor is something that may increase the chance of developing a disease.
Studies have found a number of factors that may increase the risk of cervical cancer. For example, infection with HPV (human papillomavirus) is the main cause of cervical cancer. HPV infection and other risk factors may act together to increase the risk even more:
HPV is a group of viruses that can infect the cervix. An HPV infection that doesn't go away can cause cervical cancer in some women. HPV is the cause of nearly all cervical cancers.
HPV infections are very common. These viruses are passed from person to person through sexual contact. Most adults have been infected with HPV at some time in their lives, but most infections clear up on their own.
Some types of HPV can cause changes to cells in the cervix. If these changes are found early, cervical cancer can be prevented by removing or killing the changed cells before they can become cancer cells. The NCI fact sheet Human Papillomaviruses and Cancer: Questions and Answers has more information. A vaccine for females ages 9 to 26 protects against two types of HPV infection that cause cervical cancer. The NCI fact sheet Human Papillomavirus (HPV) Vaccines: Questions and Answers has more information.
Lack of regular Pap tests
Cervical cancer is more common among women who don't have regular Pap tests. The Pap test helps doctors find abnormal cells. Removing or killing the abnormal cells usually prevents cervical cancer.
Among women who are infected with HPV, smoking cigarettes slightly increases the risk of cervical cancer.
immune system (the body's natural defense system): Infection with HIV (the virus that causes AIDS) or taking drugs that suppress the immune system increases the risk of cervical cancer.
Women who have had many sexual partners have a higher risk of developing cervical cancer. Also, a woman who has had sex with a man who has had many sexual partners may be at higher risk of developing cervical cancer. In both cases, the risk of developing cervical cancer is higher because these women have a higher risk of HPV infection.
Using birth control pills for a long time
Using birth control pills for a long time (5 or more years) may slightly increase the risk of cervical cancer among women with HPV infection. However, the risk decreases quickly when women stop using birth control pills.
Having many children
Studies suggest that giving birth to many children (5 or more) may slightly increase the risk of cervical cancer among women with HPV infection.
(diethylstilbestrol): DES may increase the risk of a rare form of cervical cancer in daughters exposed to this drug before birth. DES was given to some pregnant women in the United States between about 1940 and 1971. (It is no longer given to pregnant women.)
Having an HPV infection or other risk factors does not mean that a woman will develop cervical cancer. Most women who have risk factors for cervical cancer never develop it.