INTRODUCTION

Endometrial cancer is a type of uterine cancer that involves the lining of the uterus (the endometrium). In the United States, endometrial cancer is the most common cancer of the female reproductive system. Fortunately, most women are diagnosed at an early stage (before the cancer has spread outside the uterus), when the disease can usually be cured with surgery alone. Endometrial cancer can occur in a woman of any age, although it is much more common after menopause.

This article discusses the risk factors, symptoms, and diagnosis of the most common type of endometrial cancer, called endometrioid endometrial cancer. A separate article discusses the treatment of the endometrioid type of endometrial cancer. (See "Patient information: Endometrial cancer treatment after surgery (Beyond the Basics)".)

More detailed information about endometrial cancer is available by subscription. (See "Endometrial carcinoma: Epidemiology and risk factors" and "Endometrial carcinoma: Pretreatment evaluation, staging, and surgical treatment".)

THE UTERUS

To understand how endometrial cancer develops, it is helpful to understand the structure of the uterus. The uterus is a pear-shaped organ located between the bladder and the rectum. The cervix connects the uterus to the vagina. The inside of the uterus has two layers. The thin inner layer is called the endometrium. The thick outer layer is composed of muscle and is called the myometrium (myo = muscle) (figure 1).

In women who menstruate, the endometrium thickens every month in preparation for pregnancy. If the woman does not become pregnant, the endometrial lining is shed during the menstrual period. After menopause, when menstrual periods stop, the endometrial lining normally stops growing and shedding. In women who have endometrial cancer, the uterine lining develops abnormal cells.

ENDOMETRIAL CANCER SYMPTOMS

The most common sign of endometrial cancer is abnormal vaginal bleeding.

• In a woman who is still having menstrual periods, abnormal bleeding is defined as bleeding between menstrual periods or heavy menstrual bleeding. (See "Patient information: Abnormal uterine bleeding (Beyond the Basics)".)
• In a postmenopausal woman, any vaginal bleeding is considered abnormal, even if it is only one drop of blood. This is especially true in women who are not taking postmenopausal hormone therapy.

Women who take postmenopausal hormone therapy often have some vaginal bleeding in the first few months of treatment. However, if you are taking postmenopausal hormone therapy and you have bleeding, you should check with your doctor or nurse.

ENDOMETRIAL CANCER DIAGNOSIS AND STAGING

Your doctor or nurse might recommend testing for endometrial cancer if you have abnormal bleeding. The most commonly used tests include:

• A test that is done in the office, called endometrial biopsy.
• A test that is done as a day surgery, called hysteroscopy with dilation and curettage. (See "Patient information: Dilation and curettage (D and C) (Beyond the Basics)".)

These tests take a sample of tissue from the lining of the uterus, called the endometrium. A doctor will examine the tissue with a microscope to see if there are signs of cancer.

Tumor staging — Once endometrial cancer is diagnosed, the next step is to determine its stage. Staging is a system used to describe the spread of a cancer. Endometrial cancer's stage is based on:

• How deeply the cancer has invaded the muscle wall of the uterus
• Whether there are signs that the cancer has spread to other organs on a physical exam, MRI of the abdomen and pelvis, chest X-ray, or other imaging tests

Endometrial cancer stages range from stage I (cancer has not invaded beyond the lining of the uterus) to stage IV (the cancer has spread to distant organs, such as the liver). In general, lower stage cancers are less aggressive and require less treatment than do higher stage cancers.

Surgery — Surgery is usually done to determine how deeply the cancer has invaded the muscle wall of the uterus. At the same time, the cancer can be treated by removing the uterus, ovaries, and fallopian tubes. Surgery is done in an operating room with general anesthesia, and most women stay in the hospital for several days after the surgery.

Surgery can be done by making a vertical (up-and-down) or horizontal (left-to-right) incision in the abdomen, then examining the organs within the pelvis and abdomen for signs of cancer. This is called a laparotomy.

In other cases, surgery can be done laparoscopically, which is done through small incisions in the abdomen. The surgeon uses a thin, lighted instrument with a camera (a laparoscope) to see inside the abdomen and remove tissues.

The choice between laparotomy and laparoscopy depends on your situation and your surgeon's preference.

During the surgery, the following procedures are performed:

• The uterus and ovaries are removed (called total abdominal hysterectomy and bilateral salpingo-oophorectomy). This procedure is described in detail in a separate article. (See "Patient information: Abdominal hysterectomy (Beyond the Basics)".)
• Fluid from the abdomen and any abnormal tissue in the pelvis or abdomen are evaluated to determine whether the cancer has spread outside of the uterus
• The lymph nodes surrounding the uterus are examined. One of the first places that endometrial cancer spreads to is the lymph nodes. Swelling of the legs (lymphedema) affects approximately 5 to 40 percent of women with endometrial cancer following removal of lymph nodes.

If surgery is not possible — If surgery is too risky, such as in elderly women and women with serious medical problems, radiation therapy alone may be recommended.

ENDOMETRIAL CANCER TREATMENT

The treatment of endometrial cancer depends on how likely it is that the cancer will come back after treatment. This risk is based on:

• The stage of the cancer, which is based on what is found during surgery (see 'Tumor staging' above).
• How aggressive the tumor appears (called the tumor grade) when the tissue is examined under a microscope. High-grade tumors are usually faster growing and more likely to spread than low-grade tumors.
• What type of cells make up the tumor (called cell histology). Some cell types have a higher risk of coming back after treatment.

Depending on these characteristics, the cancer is said to have a low, intermediate, or high risk of coming back after surgery. These designations are used to decide which treatments, if any, are needed after surgery to decrease the risk of the cancer coming back.

Endometrial cancer treatment is discussed in a separate article. (See "Patient information: Endometrial cancer treatment after surgery (Beyond the Basics)".)

PREGNANCY AND ENDOMETRIAL CANCER

Although cancer is more common in postmenopausal women, it can develop in younger women. A woman with endometrial cancer who would like to have a child in the future should discuss treatment options with her doctor. (See "Patient information: Endometrial cancer treatment after surgery (Beyond the Basics)", section on 'Endometrial cancer in the young woman'.)

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient information: Uterine cancer (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient information: Endometrial cancer treatment after surgery (Beyond the Basics)
Patient information: Abnormal uterine bleeding (Beyond the Basics)
Patient information: Dilation and curettage (D and C) (Beyond the Basics)
Patient information: Abdominal hysterectomy (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Endometrial carcinoma: Epidemiology and risk factors
Endometrial carcinoma: Pretreatment evaluation, staging, and surgical treatment
Classification and diagnosis of endometrial hyperplasia
Evaluation of the endometrium for malignant or premalignant disease
Endometrial carcinoma: Histopathology and pathogenesis
Treatment of locally advanced, recurrent, or metastatic endometrial cancer
Type II endometrial carcinomas (eg, serous, clear cell, mucinous)
Uterine sarcoma: Classification, clinical manifestations, and diagnosis
Treatment and prognosis of uterine leiomyosarcoma

The following organizations also provide reliable health information.

• American Society of Clinical Oncology

      (www.cancer.net/portal/site/patient)

• National Comprehensive Cancer Network

     (http://www.nccn.org/index.asp)

• Gynecologic Oncology Group

     (www.gog.org/gynecologiccancerinformation.html)

• National Cancer Institute

     1-800-4-CANCER
     (www.cancer.gov)

Patient support — There are a number of online forums where patients can find information and support from other people with similar conditions.

• About.com Cancer Forum

     (http://cancer.about.com/forum)

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