The pear-shaped uterus is hollow and located in a woman's pelvis between her bladder and rectum. The uterus is also known as the womb, where a baby grows when a woman is pregnant. It has three sections: the cervix (the narrow, lower section), the corpus (the broad, middle section), and the fundus (the dome-shaped top section). The wall (the inside of the uterus) has two layers of tissue: endometrium (an inner layer), and myometrium (outer layer), which is muscle tissue.
Every month during a woman's childbearing years, the lining of the uterus grows and thickens in preparation for pregnancy. If the woman does not get pregnant, this thick, bloody lining passes out of her body through her vagina during menstruation. This process continues until menopause.
About uterine cancer
Uterine cancer is the most common cancer of a woman’s reproductive system. Uterine cancer begins when normal cells in the uterus change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Noncancerous conditions of the uterus include fibroids (benign tumors in the muscle of the uterus), endometriosis (endometrial tissue on the outside of the uterus or other organs), and endometrial hyperplasia (an increased number of cells in the uterine lining).
There are two major types of uterine cancer:
Adenocarcinoma. This type of cancer makes up more than 95% of uterine cancers. It develops from cells in the lining of the uterus, the endometrium. This cancer is also commonly called endometrial cancer.
Sarcoma. This form of uterine cancer develops in the myometrium (the uterine muscle) or in the supporting tissues of the uterine glands. Sarcoma accounts for about 2% to 4% of uterine cancers. Learn more about sarcoma.
Other, less common types of uterine cancer include carcinosarcoma and endometrial stromal sarcoma. Carcinosarcoma starts in the endometrium and is similar to both adenocarcinoma and sarcoma. Endometrial stromal sarcoma starts in the connective tissue of the endometrium. Treatment for these types of uterine cancer can be similar to the treatment of adenocarcinoma. Cancer specifically in the uterine cervix may be treated differently than uterine cancer; learn more about cervical cancer. The rest of this section covers endometrial (adenocarcinoma) cancer.
Find out more about basic cancer terms used in this section.
Looking for More of an Overview?
If you would like additional introductory information, explore the following item on Cancer.Net:
- ASCO Answers Fact Sheet: Read a one-page fact sheet (available in PDF) that offers an easy-to-print introduction for this type of cancer.
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