Cervical cancer affects cells in the lower portion of the uterus or the womb. This area is also known as the uterine cervix. Fetal development occurs in the upper portion, or body, of the uterus. The cervix is a term that refers to the area between the vagina and the uterus. The endocervix refers to the upper portion of the cervix, which is adjacent to the uterus. The ectocervix, or exocervix, is the lower portion of the cervix, which is adjacent to the vagina. The cells making up the endocervix are called glandular cells while the cells making up the exocervix are called squamous cells. The transformation zone is a term referring to the area where the two cell types come together. The transformation zone changes its position as part of the natural aging process and after childbirth.
The transformation zone is the area where most cervical cancers develop first. Cells do not become cancerous immediately. Normal cells undergo a gradual transformation into pre-cancerous cells that have the potential of developing into cancer. Dysplasia, squamous intraepithelial lesion, and cervical intraepithelial neoplasia are among the terms physicians use to describe this transformation. Physicians use the PAP test to detect the changes and offer treatment to prevent the development of cancer. For more information on this, read the section titled “Can Cervical Cancer Be Prevented?”
Physicians classify cervical pre-cancers and cancers according to their appearance under magnification. Adenocarcinoma and squamous cell carcinoma are the two most common cervical cancer types.
Squamous cell carcinoma accounts for as many as nine out of 10 cervical cancers. The cancer cells look like squamous cells under a microscope and begin in exocervix cells. This type of cancer typically begins where the endocervix and the exocervix come together in the transformation zone.
The majority of other cervical cancer patients are diagnosed with adenocarcinoma. This type of cervical cancer begins in the gland cells. Gland cells in the endocervix responsible for secreting mucous most often develop cervical adenocarcinoma. This type of cancer has become more prevalent over the past two to three decades.
In rare cases, cervical cancer may have characteristics of both adenocarcinoma and squamous cell carcinoma. This condition is known as mixed carcinoma or adenosquamous carcinoma.
All cervical cancer cases begin with pre-cancerous changes in cells, but only some pre-cancers develop into cancer. In some patients, pre-cancer develops into cancer within one year but in most cases, it takes several years for cancer to develop. Pre-cancerous cells disappear without treatment in most women. Some patients with pre-cancer cells are diagnosed later with cancer. Information about the specific treatment types and pre-cancer changes are included in the document titled “Cervical Cancer Prevention and Early Detection.”
Now that you know what is cervical cancer, you need to know that other types of cervical cancer may develop in addition to adenocarcinoma and squamous cell carcinoma. Sarcoma, lymphoma, and melanoma are examples although these types of cancer usually affect other body parts.
This document deals only with the most common types of cervical cancer, not rare types.