Cervical cancer is cancer that starts in the cervix, the narrow opening into the uterus from the vagina. Most cervical cancers (80-90%) are squamous cell cancers. Adenocarcinoma is the second most common type of cervical cancer (10-20%). Adenocarcinoma develops from the glands that produce mucus in the endocervix.
Cervical cancer usually develops slowly. It starts as a precancerous condition called dysplasia. This condition can be detected by a Pap smear and is treatable. The sexually transmitted human papillomavirus (HPV) is found in about 99% of cervical cancers.
There are over 100 different types of HPV, most of which are considered low-risk and typically resolve on their own. High-risk HPV types may cause cervical cell abnormalities or cancer. More than 70% of cervical cancer cases can be attributed to two high- risk types of the virus, HPV-16 and HPV-18.
Cancer of the cervix tends to occur during midlife. Half of the women diagnosed with the disease are between 35 and 55 years of age. It rarely affects women under age 20, and approximately 20 percent of diagnoses are made in women older than 65.