Cervical Cancer

The cervix is a female reproductive organ that forms the lower portion of the uterus or womb. The uterus and cervix lie in the pelvis, on top of the vagina, in between the rectum and bladder. The cervix forms the part of the birth canal that opens to the vagina.

The surface layer of the cervix is mostly composed of squamous cells. The squamous cells of the cervix merge with the glandular cells lining the cervical canal of the uterus. The area of merging is called the squamo-columnar junction and the area on the cervix outside of this junction is called the transformation zone. Cervical cancer occurs when cervical cells grow out of control, typically in the transformation zone. When cells grow out of control, they spread and grow throughout the cervix and may invade and destroy neighboring organs or break away and spread through the bloodstream and lymphatic system to other parts of the body.

Doctors who care for women routinely perform pelvic examinations and a Papanicolaou (Pap) smear to screen for cancer in the cells on the surface of the cervix. During a Pap smear, a sample of cells from the cervix is taken with a small wooden spatula or brush and examined under the microscope. Women may first become aware that they have cervical cancer when a suspicious area is identified during a pelvic examination or an abnormal Pap smear. If a suspicious or a precancerous lesion is found, additional tests will be recommended to determine whether a precancerous lesion or invasive cancer exists.

Cells taken from the surface of the cervix can appear abnormal, but may not be cancer. These abnormal cells, however, may be the first step in a series of changes that lead to cancer. Doctors refer to the abnormal cells as "precancerous" and have used different terms to refer to them, such as squamous intraepithelial lesions, dysplasia, cervical intraepithelial neoplasia or carcinoma in situ. Precancerous disease involves only the surface of the cervix. When the abnormal cells begin to spread deeper into the cervix, they are referred to as invasive cancer of the cervix.