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INTRODUCTION — Endometrial cancer is a type of uterine cancer that involves the lining of the uterus (called 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 at any age, although it is much more common in women who have been through menopause (when monthly periods stop).
This article discusses the risk factors, symptoms, and diagnosis of the most common type of endometrial cancer, called "endometrioid" endometrial cancer. The treatment of this type of endometrial cancer is discussed separately. (See "Patient education: Endometrial cancer treatment after surgery (Beyond the Basics)".)
More detailed information about endometrial cancer, written for health care providers, is available by subscription. (See 'Professional level information' below.)
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 rectum (figure 1). 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 (the prefix "myo" means "muscle").
In women who have not yet been through menopause, the endometrium thickens every month in preparation for a possible 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 education: 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 menopausal hormone therapy (ie, hormones that are often prescribed to relieve symptoms like hot flashes and vaginal dryness).
Women who take menopausal hormone therapy often have some vaginal bleeding in the first few months of treatment. However, if you are taking 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 vaginal 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 education: Dilation and curettage (D&C) (Beyond the Basics)".)
Both of these tests take a small sample of tissue from the lining of your uterus (the endometrium). A doctor will examine the tissue with a microscope to see if there are signs of cancer.
Cancer 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 (this may be determined based on a physical exam, magnetic resonance imaging [MRI] of the abdomen and pelvis, chest X-ray, or other imaging tests)
Endometrial cancer stages range from stage I (meaning the cancer has not invaded beyond the lining of the uterus) to stage IV (meaning 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 sometimes be done by laparoscopy (through small skin incisions in the abdomen, using a tool with a tiny camera to guide the surgeon). In other cases, surgery requires making a larger skin incision in the abdomen (called a laparotomy). The choice between laparoscopy and laparotomy will depend on your situation, your preferences, and your surgeon's recommendation.
Surgery involves the following steps:
●The organs in the pelvis and abdomen are examined for signs of cancer.
●The uterus and ovaries are removed (this is a called "total hysterectomy and bilateral salpingo-oophorectomy"). This procedure is described in detail in a separate article. (See "Patient education: Abdominal hysterectomy (Beyond the Basics)".)
●Fluid from the abdomen, as well as any abnormal tissue in the pelvis or abdomen, is 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. In some cases, the surgeon will do a procedure called "lymphatic mapping." This involves injecting a special substance (often a dye) in order to identify the "sentinel" lymph nodes (the nodes that are most likely to be affected first if the cancer spreads). The surgeon may then remove the sentinel lymph node(s) for testing. Swelling of the legs (lymphedema) affects approximately 5 to 40 percent of women with endometrial cancer following removal of lymph nodes; however, this risk may be lower if the surgeon removes only the sentinel lymph node(s).
If surgery is not possible — If surgery is considered too risky, such as in older women or a woman with other serious medical problems, radiation therapy alone may be recommended. (See "Patient education: Endometrial cancer treatment after surgery (Beyond the Basics)", section on 'Radiation therapy'.)
In some circumstances, hormonal therapy with intrauterine or systemic progestins may also be considered.
FACTORS THAT GUIDE TREATMENT OF ENDOMETRIAL CANCER — 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 the doctors find during surgery. (See 'Cancer 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 more detail separately. (See "Patient education: Endometrial cancer treatment after surgery (Beyond the Basics)".)
ENDOMETRIAL CANCER AND RISK OF OTHER CANCERS — Some women with endometrial cancer are at risk for having something called Lynch syndrome. This is a genetic disorder that predisposes towards various types of cancers, including endometrial, ovarian, and colorectal cancer. If you have endometrial cancer, you should talk with your doctor about whether you should be tested for Lynch syndrome. Women whose tumors display certain high-risk microscopic features, as well as those who developed endometrial cancer prior to age 50 years, and those with a concerning personal or family history of cancer should be referred for genetic counseling and testing for Lynch syndrome.
If testing finds that you do have Lynch syndrome, you will be screened for Lynch-associated cancers on a routine basis.
PREGNANCY AND ENDOMETRIAL CANCER — Although cancer is more common in postmenopausal women, it can also affect younger women. If you have been diagnosed with endometrial cancer and think you may want to have a child in the future, your doctor can talk to you about the best plan for treating your cancer as well as your possible options for future pregnancy (or alternative ways to start a family). (See "Patient education: 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 health care 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 education: 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 education: Endometrial cancer treatment after surgery (Beyond the Basics)
Patient education: Abnormal uterine bleeding (Beyond the Basics)
Patient education: Dilation and curettage (D&C) (Beyond the Basics)
Patient education: 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, risk factors, and prevention
Endometrial carcinoma: Staging and surgical treatment
Endometrial hyperplasia: Clinical features, diagnosis, and differential diagnosis
Overview of the evaluation of the endometrium for malignant or premalignant disease
Endometrial cancer: Pathology and classification
Management of locoregional recurrence of endometrial cancer
Endometrial carcinoma: Serous and clear cell histologies
Uterine sarcoma: Classification, epidemiology, clinical manifestations, and diagnosis
Treatment and prognosis of uterine leiomyosarcoma
The following organizations also provide reliable health information.
●American Society of Clinical Oncology
●Gynecologic Oncology Group
●National Cancer Institute
1-800-4-CANCER
