What is cervical cancer?
Cancer of the cervix (cervical cancer) is caused by the uncontrolled growth of cells in the cervix. The cervix is the narrowed bottom portion of a woman's uterus. Shaped like a cone, it connects the uterus to the vagina and is the "gateway" of the birth canal.
The American Cancer Society estimates that more than 12,000 women develop cervical cancer each year in the United States and about 4,200 die from the disease. Invasive cervical cancer was once a very common disease in the U.S. Since the introduction of the Papanicolaou (Pap) smear, a screening tool that allows the detection of cancerous and precancerous changes in the cervix, rates of cervical cancer in the U.S. and other industrialized nations have dropped by as much as 70%. However, in certain populations of the U.S. and in developing nations where access to health care and screening programs are limited, cervical cancer is still a very serious concern. Worldwide, cervical cancer continues to be the second most common type of cancer in women (after breast cancer). Each year, about 500,000 women are diagnosed with cervical cancer and approximately 250,000 die from it.
Cervical cancer begins slowly. The earliest, precancerous changes cause the cells lining the inside or outside of the cervix to appear different from normal cervical cells. These changes, when present on a Pap smear, are termed "atypical cells." Atypical cells are not entirely specific for a precancerous condition, however, and can temporarily appear in response to infections or irritation of the cervix lining. If precancerous, the atypical cells can become more abnormal in appearance over time and are more likely to progress to cancer if left untreated. In Pap smears, these more abnormal (intermediate) cellular changes are called low-grade or high-grade squamous intraepithelial lesions [see the sidebar on Pap smear terminology]. If these cells become cancerous, they are initially limited to the surface lining (in situ). Without treatment, the cancer cells can become invasive by growing into the supporting tissues of the cervix and can potentially spread to other body sites.
About 80-90% of cervical cancers are squamous cell carcinomas, occurring in the flat squamous cells that cover the outside of the cervix. Most other cases are adenocarcinomas, rising from mucus-producing gland cells of the opening of the cervix (the endocervix). A few cervical cancers are mixtures of both types.
With early detection, cervical cancer is usually easily treatable. Left unchecked, however, it is almost always fatal. Given time, cervical cancer can spread (metastasize) to the rest of the uterus, the bladder, the rectum, and the abdominal wall. Eventually, it can reach the pelvic lymph nodes and metastasize further, invading other organs throughout the body.