Font Size
A
A
A
1
...

Endometrial Cancer

Endometrial Cancer Overview

The endometrium is the tissue lining the uterus (or womb). The uterus, a hollow organ about the size and shape of a pear, is found in a woman's pelvic region and is the organ where the fetus grows until birth. The upper part of the uterus is called the corpus; the lower, narrower part of the uterus is called the cervix. The cervix is the opening between the uterus and the vagina. The outer layer of the uterus is called the myometrium. The myometrium is thick and composed of strong muscles. These muscles contract during labor to push out the baby.

The endometrium is soft and spongy. Each month, the endometrium changes as part of the menstrual cycle. Early in the cycle, the ovaries secrete a hormone called estrogen that causes the endometrium to thicken. In the middle of the cycle, the ovaries start secreting another hormone called progesterone. Progesterone prepares the innermost layer of the endometrium to support an embryo should conception (pregnancy) occur. If conception does not occur, the hormone levels decrease dramatically. The innermost layer of the endometrium is then shed as menstrual fluid. This leads to the cyclical nature of the menstrual cycle.

Endometrial cancer occurs when cells of the endometrium undergo a transformation and begin to grow and multiply without the control mechanisms that normally limit their growth. As the cells grow and multiply, they form a mass called a tumor. Cancer is dangerous because it overwhelms healthy cells by taking their space and the oxygen and nutrients they need to survive and function.

Not all tumors are cancerous. Cancerous tumors are called malignant, meaning they can spread to other tissues and organs. Cancerous tumors may encroach on and invade neighboring organs or lymph nodes, or they may enter the bloodstream and spread to the bones or distant organs, such as the lungs. This process is called metastasis. Metastatic tumors are the most aggressive and serious of all tumors.

Two main types of endometrial cancers exist. Nearly all endometrial cancers are endometrial adenocarcinomas, meaning they originate from glandular (secreting) tissue. The other type of endometrial cancer, uterine sarcomas, originates in the connective tissue or muscle of the uterus. A subtype of endometrial adenocarcinomas, adenosquamous carcinoma, includes squamous cells (that is, the type of cells found on the surface of the skin and cervix). Other subtypes of endometrial adenocarcinomas are papillary serous adenocarcinomas and clear cell carcinomas. Because they are much more common than uterine sarcomas, endometrial adenocarcinomas are the focus of this article.

In developed countries, uterine cancer is the most common cancer of the female genital tract. In the United States, uterine cancer is the fourth most common cancer in women. Uterine cancer occurs in women of reproductive age and older. About one-quarter of cases occur before menopause, but the disease is most often diagnosed in women in their 50s or 60s.

Endometrial Cancer Causes and Risk Factors

The exact cause of endometrial carcinoma remains unknown, although several risk factors have been identified. Possessing one of these risk factors does not mean that a woman will develop endometrial cancer but rather that her risk of developing endometrial cancer is higher than that of another woman without the risk factor. Risk factors for endometrial cancer include the following:

  • Obesity: Women who are more than 50 pounds over ideal weight have a 10-times greater risk of developing endometrial cancer than women of ideal weight. Body fat produces estrogen, and women with excess fat have a higher level of estrogen than women without excess fat. The higher level of estrogen is believed to increase the risk of cancer.
  • No pregnancies: Women who have never been pregnant have a two-to three-times higher risk than women who have been pregnant.
  • Early puberty: Women who begin their periods before 12 years of age are at an increased risk. Early puberty increases the number of years that the endometrium is exposed to estrogen.
  • Late menopause: Women who go through menopause after 52 years of age are at a higher risk of developing endometrial cancer than women who go through menopause earlier in life. Like early puberty, late menopause increases the number of years that the endometrium is exposed to estrogen.
  • Treatment with unopposed estrogen: The risk of developing endometrial cancer is increased by several times in women who take estrogen replacement therapy without added progesterone.
  • High level of estrogen: Women who have a high level of unopposed estrogen in the body are also at an increased risk. Several different conditions, such as polycystic ovarian syndrome, can cause a woman to have a high unopposed estrogen level.
  • Treatment with tamoxifen: Women who have been treated with tamoxifen, a drug used to prevent and treat breast cancer, may have a slightly increased risk of developing endometrial cancer.
  • Other cancers: Cancers of the breast, ovary, and colon are linked with an increased risk of endometrial cancer.
  • Family history: Women who have a close relative with endometrial cancer have an increased risk of the disease.

The use of combination oral contraceptives (birth control pills) decreases the risk of developing endometrial cancer.

  • Women who use oral contraceptives at some time have half the risk of developing endometrial cancer as women who have never used oral contraceptives.
  • This protection occurs in women who have used oral contraceptives for at least 12 months.
  • The protection continues for at least 10 years after oral contraceptive use. The protection is most notable for women who have never been pregnant.
Medically Reviewed by a Doctor on 6/2/2014
Medical Author:

Must Read Articles Related to Endometrial Cancer

Dilation and Curettage (D&C)
Dilation and Curettage (D&C) The dilation and curettage procedure (D&C). This is a save procedure that a woman may need to have performed for a variety of reasons such as irregular bleeding...learn more >>

Patient Comments & Reviews

The eMedicineHealth doctors ask about Endometrial Cancer:

Endometrial Cancer - Symptoms

What were your symptoms of endometrial cancer?



NIH talks about Ebola on WebMD

Read What Your Physician is Reading on Medscape

Endometrial Carcinoma »

Corpus cancer is the most frequently occurring female genital cancer.

Read More on Medscape Reference »


Medical Dictionary