Cervical Cancer Information
What is Cervical Cancer?
Cervical cancer, or invasive cervical cancer, occurs when abnormal cells spread deeper into the cervix or to other tissues or organs. Cervical cancer occurs most often in women over the age of 40. In order to best understand the following information on cervical cancer, you first need to know how the cervix works. The cervix is the lower, narrow part of the uterus (womb). The uterus, a hollow, pear-shaped organ, is located in a woman's lower abdomen, between the bladder and the rectum. The cervix forms a canal that opens into the vagina, which leads to the outside of the body.
Cells on the surface of the cervix sometimes appear abnormal but do not lead to cervical cancer. Scientists believe that some abnormal changes in cells on the cervix are the first step in a series of slow changes that can lead to cervical cancer years later. That is, some abnormal changes are precancerous; they may become cancerous with time.
Over the years, doctors have used different terms to refer to abnormal changes in the cells on the surface of the cervix. One term now used is squamous intraepithelial lesion (SIL). (The word lesion refers to an area of abnormal tissue; intraepithelial means that the abnormal cells are present only in the surface layer of cells.) Changes in these cells can be divided into two categories:
Low-grade SIL refers to early changes in the size, shape, and number of cells that form the surface of the cervix. Some low-grade lesions go away on their own. However, with time, others may grow larger or become more abnormal, forming a high-grade lesion, which could lead to cervical cancer. Precancerous low-grade lesions also may be called mild dysplasia or cervical intraepithelial neoplasia 1 (CIN 1). Such early changes in the cervix most often occur in women between the ages of 25 and 35 but can appear in other age groups as well.
High-grade SIL means there are a large number of precancerous cells; they look very different from normal cells. Like low-grade SIL, these precancerous changes involve only cells on the surface of the cervix. The cells will not become cancerous and invade deeper layers of the cervix for many months, perhaps years. High-grade lesions also may be called moderate or severe dysplasia, CIN 2 or 3, or carcinoma in situ. They develop most often in women between the ages of 30 and 40 but can occur at other ages as well.