Endometrial (Uterine) Cancer

Overview:
The uterus is part of a woman's reproductive system. It is the hollow, pear-shaped organ where a baby grows. The uterus is in the pelvis between the bladder and the rectum. 

The narrow, lower portion of the uterus is the cervix. The broad, middle part of the uterus is the body, or corpus. The dome-shaped top of the uterus is the fundus. The fallopian tubes extend from either side of the top of the uterus to the ovaries.
Uterus
Uterus and other reproductive organs

The wall of the uterus has two layers of tissue. The inner layer, or lining, is the endometrium. The outer layer is muscle tissue called the myometrium.

In women of childbearing age, the lining of the uterus grows and thickens each month to prepare for pregnancy. If a woman does not become pregnant, the thick, bloody lining flows out of the body through the vagina. This flow is called menstruation.

 The most common type of cancer of the uterus begins in the lining (endometrium). It is called endometrial cancer, uterine cancer, or cancer of the uterus. In this booklet, we will use the terms uterine cancer or cancer of the uterus to refer to cancer that begins in the endometrium.

A different type of cancer, uterine sarcoma, develops in the muscle (myometrium). Cancer that begins in the cervix is also a different type of cancer. This booklet does not deal with uterine sarcoma or with cancer of the cervix.

Risk Factors:
No one knows the exact causes of uterine cancer. However, it is clear that this disease is not contagious. No one can "catch" cancer from another person.

Women who get this disease are more likely than other women to have certain risk factors. A risk factor is something that increases a person's chance of developing the disease.

Most women who have known risk factors do not get uterine cancer. On the other hand, many who do get this disease have none of these factors. Doctors can seldom explain why one woman gets uterine cancer and another does not.

Studies have found the following risk factors:

  • Age: Cancer of the uterus occurs mostly in women over age 50.
  • Endometrial hyperplasia: The risk of uterine cancer is higher if a woman has endometrial hyperplasia. This condition and its treatment are described above.
  • Hormone replacement therapy (HRT): HRT is used to control the symptoms of menopause, to prevent osteoporosis (thinning of the bones), and to reduce the risk of heart disease or stroke.
    Women who use estrogen without progesterone have an increased risk of uterine cancer. Long-term use and large doses of estrogen seem to increase this risk. Women who use a combination of estrogen and progesterone have a lower risk of uterine cancer than women who use estrogen alone. The progesterone protects the uterus.
    Women should discuss the benefits and risks of HRT with their doctor. Also, having regular checkups while taking HRT may improve the chance that the doctor will find uterine cancer at an early stage, if it does develop.
  • Obesity and related conditions: The body makes some of its estrogen in fatty tissue. That's why obese women are more likely than thin women to have higher levels of estrogen in their bodies. High levels of estrogen may be the reason that obese women have an increased risk of developing uterine cancer. The risk of this disease is also higher in women with diabetes or high blood pressure (conditions that occur in many obese women).
  • Tamoxifen: Women taking the drug tamoxifen to prevent or treat breast cancer have an increased risk of uterine cancer. This risk appears to be related to the estrogen-like effect of this drug on the uterus. Doctors monitor women taking tamoxifen for possible signs or symptoms of uterine cancer.
    The benefits of tamoxifen to treat breast cancer outweigh the risk of developing other cancers. Still, each woman is different. Any woman considering taking tamoxifen should discuss with the doctor her personal and family medical history and her concerns.
  • Race: White women are more likely than African-American women to get uterine cancer.
  • Colorectal cancer: Women who have had an inherited form of colorectal cancer have a higher risk of developing uterine cancer than other women.

Other risk factors are related to how long a woman's body is exposed to estrogen. Women who have no children, begin menstruation at a very young age, or enter menopause late in life are exposed to estrogen longer and have a higher risk.

Women with known risk factors and those who are concerned about uterine cancer should ask their doctor about the symptoms to watch for and how often to have checkups. The doctor's advice will be based on the woman's age, medical history, and other factors.

Screening:
If a woman has symptoms that suggest uterine cancer, her doctor may check general signs of health and may order blood and urine tests. The doctor also may perform one or more of the exams or tests described below.

  • Pelvic exam -- A woman has a pelvic exam to check the vagina, uterus, bladder, and rectum. The doctor feels these organs for any lumps or changes in their shape or size. To see the upper part of the vagina and the cervix, the doctor inserts an instrument called a speculum into the vagina.
  • Pap test -- The doctor collects cells from the cervix and upper vagina. A medical laboratory checks for abnormal cells. Although the Pap test can detect cancer of the cervix, cells from inside the uterus usually do not show up on a Pap test. This is why the doctor collects samples of cells from inside the uterus in a procedure called a biopsy.
  • Transvaginal ultrasound -- The doctor inserts an instrument into the vagina. The instrument aims high-frequency sound waves at the uterus. The pattern of the echoes they produce creates a picture. If the endometrium looks too thick, the doctor can do a biopsy.
  • Biopsy -- The doctor removes a sample of tissue from the uterine lining. This usually can be done in the doctor's office. In some cases, however, a woman may need to have a dilation and curettage (D&C). A D&C is usually done as same-day surgery with anesthesia in a hospital. A pathologist examines the tissue to check for cancer cells, hyperplasia, and other conditions. For a short time after the biopsy, some women have cramps and vaginal bleeding.

Symptoms:
Uterine cancer usually occurs after menopause. But it may also occur around the time that menopause begins. Abnormal vaginal bleeding is the most common symptom of uterine cancer. Bleeding may start as a watery, blood-streaked flow that gradually contains more blood. Women should not assume that abnormal vaginal bleeding is part of menopause. 

A woman should see her doctor if she has any of the following symptoms:

  • Unusual vaginal bleeding or discharge
  • Difficult or painful urination
  • Pain during intercourse
  • Pain in the pelvic area

These symptoms can be caused by cancer or other less serious conditions. Most often they are not cancer, but only a doctor can tell for sure.

Staging:
If uterine cancer is diagnosed, the doctor needs to know the stage, or extent, of the disease to plan the best treatment. Staging is a careful attempt to find out whether the cancer has spread, and if so, to what parts of the body.

The doctor may order blood and urine tests and chest x-rays. The woman also may have other x-rays, CT scans, an ultrasound test, magnetic resonance imaging (MRI), sigmoidoscopy, or colonoscopy.

In most cases, the most reliable way to stage this disease is to remove the uterus (hysterectomy). (The description of surgery in the "Methods of Treatment" section has more information.) After the uterus has been removed, the surgeon can look for obvious signs that the cancer has invaded the muscle of the uterus. The surgeon also can check the lymph nodes and other organs in the pelvic area for signs of cancer. A pathologist uses a microscope to examine the uterus and other tissues removed by the surgeon.

These are the main features of each stage of the disease:

  • Stage I -- The cancer is only in the body of the uterus. It is not in the cervix.
  • Stage II -- The cancer has spread from the body of the uterus to the cervix.
  • Stage III -- The cancer has spread outside the uterus, but not outside the pelvis (and not to the bladder or rectum). Lymph nodes in the pelvis may contain cancer cells.
  • Stage IV -- The cancer has spread into the bladder or rectum. Or it has spread beyond the pelvis to other body parts.

Treatment:
Women with uterine cancer have many treatment options. Most women with uterine cancer are treated with surgery. Some have radiation therapy. A smaller number of women may be treated with hormonal therapy. Some patients receive a combination of therapies.

The doctor is the best person to describe the treatment choices and discuss the expected results of treatment.

A woman may want to talk with her doctor about taking part in a clinical trial, a research study of new treatment methods. Clinical trials are an important option for women with all stages of uterine cancer. The section on "The Promise of Cancer Research" has more information about clinical trials.

Most women with uterine cancer have surgery to remove the uterus (hysterectomy) through an incision in the abdomen. The doctor also removes both fallopian tubes and both ovaries. (This procedure is called a bilateral salpingo-oophorectomy.)

The doctor may also remove the lymph nodes near the tumor to see if they contain cancer. If cancer cells have reached the lymph nodes, it may mean that the disease has spread to other parts of the body. If cancer cells have not spread beyond the endometrium, the woman may not need to have any other treatment. The length of the hospital stay may vary from several days to a week.

In radiation therapy, high-energy rays are used to kill cancer cells. Like surgery, radiation therapy is a local therapy. It affects cancer cells only in the treated area.

Some women with Stage I, II, or III uterine cancer need both radiation therapy and surgery. They may have radiation before surgery to shrink the tumor or after surgery to destroy any cancer cells that remain in the area. Also, the doctor may suggest radiation treatments for the small number of women who cannot have surgery.

Doctors use two types of radiation therapy to treat uterine cancer:

  • External radiation: In external radiation therapy, a large machine outside the body is used to aim radiation at the tumor area. The woman is usually an outpatient in a hospital or clinic and receives external radiation 5 days a week for several weeks. This schedule helps protect healthy cells and tissue by spreading out the total dose of radiation. No radioactive materials are put into the body for external radiation therapy.
  • Internal radiation: In internal radiation therapy, tiny tubes containing a radioactive substance are inserted through the vagina and left in place for a few days. The woman stays in the hospital during this treatment. To protect others from radiation exposure, the patient may not be able to have visitors or may have visitors only for a short period of time while the implant is in place. Once the implant is removed, the woman has no radioactivity in her body.

Some patients need both external and internal radiation therapies.

Hormonal therapy involves substances that prevent cancer cells from getting or using the hormones they may need to grow. Hormones can attach to hormone receptors, causing changes in uterine tissue. Before therapy begins, the doctor may request a hormone receptor test. This special lab test of uterine tissue helps the doctor learn if estrogen and progesterone receptors are present. If the tissue has receptors, the woman is more likely to respond to hormonal therapy.

Hormonal therapy is called a systemic therapy because it can affect cancer cells throughout the body. Usually, hormonal therapy is a type of progesterone taken as a pill.

The doctor may use hormonal therapy for women with uterine cancer who are unable to have surgery or radiation therapy. Also, the doctor may give hormonal therapy to women with uterine cancer that has spread to the lungs or other distant sites. It is also given to women with uterine cancer that has come back.

Source: National Cancer Institute