Cervical cancer is usually a slow growing malignancy that begins in the lining of the cervix. Normal cervical cells can gradually develop precancerous changes that turn into cancer. Providers use several terms to describe these precancerous changes, including cervical intraepithelial neoplasia or CIN, squamous intraepithelial lesion or SIL, and dysplasia.
There are two main types of cervical cancers: squamous cell carcinoma and adenocarcinoma. Cervical cancers and cervical precancers are classified by how they look under a microscope. 80 - 90% of cervical cancers are squamous cell carcinomas, which most often begin where the ectocervix joins the endocervix.
The remaining 10 - 20% of cervical cancers are classified as adenocarcinomas. Unfortunately, adenocarcinomas are becoming more common. This type of cervical cancer develops from the mucus-producing gland cells of the endocervix.
In some uncommon cases, cervical cancer can have characteristics of both squamous cell carcinomas and adenocarcinomas. These conditions are called adenosquamous carcinomas or mixed carcinomas.
It’s important to keep in mind that not all women with precancerous changes of the cervix will develop cancer. For most women, precancerous cells will remain unchanged and go away without any treatment. It’s hopeful to note that if these precancers are treated, in most cases cervical cancer can be prevented.