Uterine Cancer: Introduction

Approved by the Cancer.Net Editorial Board, 06/2017

ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Uterine Cancer. Use the menu to see other pages. Think of that menu as a roadmap for this complete guide.

About the uterus

The pear-shaped uterus is hollow and located in a woman’s pelvis between the bladder and rectum. The uterus, also known as the womb, is where a baby grows when a woman is pregnant. It has 3 sections: the narrow, lower section called the cervix; the broad section in the middle called the isthmus; and the dome-shaped top section called the fundus. The wall on the inside of the uterus has 2 layers of tissue: endometrium (inner layer) and myometrium (outer layer), which is muscle tissue.

During a woman's childbearing years, her ovaries typically release an egg every month and the lining of the uterus grows and thickens in preparation for pregnancy. If the woman does not get pregnant, this thick lining passes out of her body through her vagina, a process known as menstruation. This process continues until menopause, when a woman’s ovaries stop releasing eggs.

About uterine cancer

Uterine cancer is the most common cancer occurring in a woman’s reproductive system. Uterine cancer begins when healthy cells in the uterus change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor can grow but generally will not invade other tissues.

Noncancerous conditions of the uterus include:

  • Fibroids: Benign tumors in the muscle of the uterus

  • Benign polyps: Abnormal growths in the lining of the uterus

  • Endometriosis: A condition in which endometrial tissue, which usually lines the inside of the uterus, is found on the outside of the uterus or other organs.

  • Endometrial hyperplasia: A condition in which there is an increased number of cells and glandular structures in the uterine lining. Endometrial hyperplasia can have either normal or atypical cells and simple or complex glandular structures. The risk for developing cancer in the lining of the uterus is higher when endometrial hyperplasia has atypical cells and complex glands.

There are 2 major types of uterine cancer:

  • Adenocarcinoma. This type makes up more than 80% of uterine cancers. It develops from cells in the endometrium. This cancer is commonly called endometrial cancer. One common endometrial adenocarcinoma is called endometrioid carcinoma, and treatment varies depending on the grade of the tumor, how far it goes into the uterus, and the stage or extent of disease (see Stages and Grades). A less common type is called endometrial serous carcinoma. This form is treated like ovarian cancer, which is also commonly of the serous type.

  • Sarcoma. This type of uterine cancer develops in the supporting tissues of the uterine glands or in the myometrium, which is the uterine muscle. Sarcoma accounts for about 2% to 4% of uterine cancers. In most situations, sarcomas are treated differently than adenocarcinomas. Types of endometrial sarcoma include leiomyosarcoma and endometrial stromal sarcoma. Learn more about sarcoma.

Cancer confined to the uterine cervix is treated differently than uterine cancer; learn more about cervical cancer. The rest of this section covers the more common endometrial (adenocarcinoma) cancer.

About genetics and family history and uterine cancer

A higher risk for uterine cancers can be inherited, passed from generation to generation, or may skip 1 generation to appear in the next. This happens about 5% of the time, and the syndrome associated with inherited uterine cancer is called Lynch syndrome. Lynch syndrome is associated with several other types of cancer, including types of colon, kidney, bladder, and ovarian cancers.

When cells divide and multiply, DNA errors can occur. There are 6 proteins in the body that fix these errors. If 1 of these proteins does not work properly, errors in the DNA can accumulate and yield enough DNA damage that cancer may develop. This problem with DNA repair is called mismatch repair defect (MMR). MMR is the main sign of Lynch syndrome.

Your cancer can be tested for Lynch syndrome through a special staining process called immunohistochemistry (IHC). If IHC shows that your cancer lacks 1 of these DNA repair proteins or if you have a family history of a cancer associated with Lynch syndrome, discuss this with your doctor or talk with a genetic counselor. Family members may wish to be tested, too. People affected by Lynch syndrome should tell their doctors so they can receive increased screening for Lynch-associated cancers. Other family members may consider preventive surgery for uterine and ovarian cancer. Learn more about Lynch syndrome.

Looking for More of an Introduction?

If you would like more of an introduction, explore the following item. Please note that these links will take you to other sections on Cancer.Net:

  • ASCO Answers Fact Sheet: Read a 1-page fact sheet that offers an introduction to this type of cancer. This fact sheet is available as a PDF, so it is easy to print out.

The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with this disease and general survival rates. You may use the menu to choose a different section to read in this guide.