The cervix is a small, donut-shaped structure. It is located at the top of the vagina. It is the entrance to the uterus.
Cervical cancer begins in the outer layer of the cervix. This outer layer is called the cervical epithelium. Tiny changes begin in epithelial cells. Over time, cells may become cancerous and grow out of control.
Cervical cancer usually grows slowly. It can remain in the cervical covering for up to 10 years. Once cervical cancer moves beyond this layer, it invades nearby tissue. This includes the uterus, vagina, bladder, and rectum.
Almost all cervical cancer is caused by infection with human papilloma virus (HPV). HPV can damage the cells that line the cervix. Sometimes the damage occurs in the genes of the cells, which may lead to cervical cancer.
HPV is a very common infection among sexually active women. But only a small number of women with HPV develop cervical cancer.
Smokers are more likely to develop cervical abnormalities if they are infected with HPV. Women infected with human immunodeficiency virus (HIV) are also at higher risk.