Cervical Cancer - Introduction

Introduction

The cervix is the lower third portion of the uterus (womb). It serves as a neck to connect the uterus to the vagina. The opening of the cervix, called the os, remains small and narrow, except during childbirth when it widens to allow a baby to pass from the uterus into the vagina.

Cervical cancer develops in the thin layer of cells called the epithelium, which cover the cervix. Cells found in the this tissue have different shapes:

• Squamous cells (flat and scaly). Most cervical cancer arises from changes in the squamous cells of the epithelium (squamous cell carcinoma).
• Columnar cells (column-like). These cells line the cervical glands and cancers here are known as adenocarcinomas.
• In rare cases, cancer can occur in cells that form the supportive tissue around the cervix (the stroma).

Cervical cancer usually begins slowly with precancerous abnormalities, and even if cancer develops, it generally progresses very gradually. Cervical cancer is the most preventable type of cancer and is very treatable in its early stages. Regular Pap tests and human papilloma virus (HPV) screening can help detect this disease early.

Precancerous Changes in the Cervix

Dysplasia. Dysplasia is a term that refers to a precancerous condition. It may become cancerous, but not always. In the case of cervical cancer, dysplasia indicates that the layer of cells that covers the cervix (squamous epithelial cells) are abnormal in size and shape and are beginning to grow.

Cervical Intraepithelial Neoplasia (CIN). Dysplastic changes seen on a Pap smear may indicate the presence of cervical intraepithelial neoplasia (CIN). This means precancerous changes are found within the lining of the cervix. The changes are categorized according to severity: CIN I, CIN II, and CIN III (which includes carcinoma in situ).