Facts & Resources

Understanding Endometrial Cancer

Fred Hutchinson Cancer Center has more gynecologic oncologists than any other medical center or clinic in the Pacific Northwest. Our providers specialize in treating gynecologic cancers, including endometrial cancer. 

Endometrial cancer is the most common cancer of the reproductive organs among American women and anyone who menstruates. It can often be cured, especially when diagnosed early. About 46,000 new cases of endometrial cancer are diagnosed every year in this country. Most people with endometrial cancer are diagnosed after menopause, although some women develop the disease earlier, around the time menopause begins.

What is Endometrial Cancer?

The terms “endometrial cancer” and “uterine cancer” are sometimes used interchangeably, but they don’t mean exactly the same thing.

Endometrial cancer develops from a specific part of the uterus—the endometrium, which is the inner lining of the uterus. During your menstrual cycle, this lining thickens so it’s ready to support an embryo if your egg is fertilized. If the egg isn’t fertilized, the innermost layer of the endometrium is shed. This shedding is your menstrual flow. It’s regulated by the hormones estrogen and progesterone.

Most uterine cancers—more than 95 percent—start in the endometrium. These cancers are called endometrial cancers or endometrial carcinomas. (“Carcinoma” is the term for cancer that starts in one of the body’s linings.) Nearly all endometrial cancers start in the glandular cells of the endometrium. These cancers are called endometrioid adenocarcinomas.

Endometrial cancer occurs when cells in the endometrium begin to grow abnormally. They do not respond to regular cell growth, division, and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may break through underlying layers of the uterus.

Cancer can also start in other parts of the uterus besides the endometrium, such as in the uterus’s thick outer layer of muscle (where it’s called uterine leiomyosarcoma) or in the connective tissue that supports the endometrium (where it’s called endometrial stromal sarcoma). These less common uterine sarcomas are discussed in the uterine sarcoma section.

Cancer can start in the cervix, the narrow part at the bottom of the uterus, too. This is referred to as cervical cancer, not uterine cancer.


Many people who have symptoms of endometrial cancer (vaginal bleeding after menopause or abnormal menstrual bleeding) may have a biopsy that shows precancerous changes of the endometrium, called complex hyperplasia with atypia. Risk is high that 25 to 50 percent of these women will go on to develop endometrial cancer.

To reduce the risk, physicians usually advise women with this condition to have a hysterectomy (surgery to remove the uterus) if they are past childbearing years or do not intend to become pregnant. Many gynecologists refer these women to a gynecologic oncologist for their surgery because of the chance of finding true cancer at the time of the hysterectomy.

For younger patients who hope to preserve their ability to have children, physicians may sometimes take a more conservative approach, using hormone therapy (usually progestins) to reduce cancer risk and doing close follow-up to watch for any signs of cancer.

Types of Treatment for Endometrial Cancer

If you have been diagnosed with endometrial cancer, you should know that this is the most common cancer of the female reproductive organs among American people. It can often be cured, especially when diagnosed early.

If you have been referred to Fred Hutch for treatment, here are some of the treatment choices you may be offered. 

Risk Factors

Endometrial cancer rarely affects people before age 40. Most people with endometrial cancer are 50 years old or older.

Risk Factors

Besides age, another important risk factor is your balance of the hormones estrogen and progesterone. Factors that shift your balance toward more estrogen can increase your risk. This is why the following are risk factors:

  • Taking hormone replacement therapy (HRT) for menopause with estrogen alone. (People who have a uterus and who take HRT can take a form that combines estrogen and progestins, which are progesterone-like drugs, to avoid increased risk for endometrial cancer. Discuss your HRT options with your physician.)
  • Having more menstrual periods—starting your period earlier in life or going through menopause later.
  • Never being pregnant.
  • Being overweight or obese (because body fat raises your estrogen level).

Other Factors That May Increase Your Risk

  • Taking tamoxifen (Nolvadex) for breast cancer treatment
  • Having breast cancer, ovarian cancer, polycystic ovary syndrome, or diabetes
  • Eating a high-fat diet
  • Having a sedentary lifestyle
  • Having a family history of endometrial cancer
  • Having Lynch syndrome
  • Having had radiation therapy to your pelvic area before
  • Having had endometrial hyperplasia, especially complex hyperplasia with atypia

Taking birth control pills lowers your risk for endometrial cancer.

Signs and Symptoms

When endometrial cancer is diagnosed, it’s usually because a someone sees their physician about symptoms.

The most common symptom of endometrial cancer is abnormal vaginal bleeding, such as bleeding or spotting between periods or after menopause. Some people have other abnormal vaginal discharge that doesn’t appear to have blood in it.

The following may be signs or symptoms of endometrial cancer, but they are uncommon:

  • Difficult or painful urination
  • Pain during intercourse
  • Pain in the pelvic area
  • A mass in the pelvic area
  • Unexplained weight loss

Conditions other than cancer may cause these signs and symptoms. If you have any of these, see your physician to find out the reason.


If you have signs or symptoms that could be from endometrial cancer (or another problem with your reproductive organs), your physician will probably start by doing a general physical exam and then a pelvic exam.

To diagnose endometrial cancer, physicians have to remove a small sample of tissue from your endometrium and look at the cells under a microscope.

Endometrial Biopsy

The most common and most accurate way to diagnose endometrial cancer is with an endometrial biopsy. The doctor inserts a thin, flexible, straw-like tube into your uterus through your cervix and scrapes or suctions out a small amount of endometrium. A pathologist examines the tissue samples. Fred Hutch has a dedicated pathologist who specializes in the diagnosis of gynecologic cancers.

Dilation and Curettage

Less often, people need dilation and curettage (D&C). A narrow instrument called a dilator is inserted into your cervix to open it. Next the physician uses a spoon-like tool called a curette to scrape some tissue from inside your uterus. The most common reason a person might need a D&C instead of an endometrial biopsy is because she has cervical stenosis—the passageway through her cervix is too narrow to do a biopsy or it’s completely closed.

Imaging Studies

The only way to tell whether you have endometrial cancer is to examine samples of tissue. In certain situation, your doctor may also want you to have imaging studies to get more information, such as whether your cancer has spread. These might include an X-ray, ultrasound, computed tomography (CT) scan, and magnetic resonance imaging (MRI) scan.


Once endometrial cancer has been diagnosed, physicians perform tests to determine the stage of the cancer. Staging is the process of determining:

  • The grade of your cancer (how abnormal the cells look and how likely the cancer is to grow and spread)
  • Whether (and how deeply) it has invaded your uterus’s muscle layer
  • Whether it has spread outside your uterus

Physicians use a cancer’s stage as a key factor in making treatment recommendations and estimating a patient’s chance for recovery. For endometrial cancer, staging is typically done at the time of surgery, which means you and your healthcare team will probably need to wait until after surgery to make some of your treatment decisions.

The most common staging system for gynecological cancers is the International Federation of Gynecology and Obstetrics (FIGO) 2010 system. This is the system that gynecologic oncologists at Fred Hutch use.

  • Stage I: Cancer is only in the body of the uterus (that is, only in the upper uterus, not in the cervix). It may have spread from the endometrium into the myometrium. There’s no cancer in the supporting connective tissue (stroma) of the cervix or outside the uterus.
  • Stage II: Cancer has spread to the supporting connective tissue of the cervix but not beyond the uterus.
  • Stage III: Cancer has spread outside the uterus to nearby tissue in the pelvic area—the outer surface of the uterus (serosa), the fallopian tubes, the ovaries, the vagina, the parametrium (tissue around the uterus), or regional lymph nodes (pelvic or para-aortic nodes). It has not spread outside the pelvic area.
  • Stage IV: Cancer has spread to the bladder or bowel, lymph nodes in the groin (inguinal nodes), or organs outside the pelvis, such as the lungs, liver, or bones.

Fred Hutch has researched and treated endometrial cancer for decades.


There are many resources online for learning about your disease. We’ve compiled a list of trusted sources to help you get started.

If you or your caregiver are seeking additional information or resources, our Patient and Family Resource Center is available to help connect you with what you need.

Cancer Research Organizations

Our list of online resources provides accurate health information from reliable and reputable sources, like the National Cancer Institute (NCI), the American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN).

American Cancer Society

American Cancer Society (ACS): Overview of Endometrial Cancer

If you have endometrial cancer or are a caregiver for someone who does, knowing what to expect can be helpful. Here you can find out all about endometrial cancer in adults, including risk factors, symptoms and how they are found and treated.

American Society of Clinical Oncology

American Society of Clinical Oncology (ASCO): Guide to Uterine Cancer

This is Cancer.Net's Guide to uterine cancers, which includes endometrial cancer. Here you can learn more about uterine cancers, treatment, the latest research and clinical trials. 

American Society of Clinical Oncology

ASCO Answers: Uterine Cancer

ASCO Answers is a collection of oncologist-approved patient education materials developed by ASCO for people with cancer and their caregivers. Here you can find illustrations and information on uterine cancers, which includes endometrial cancer.

National Cancer Institute

National Cancer Institute (NCI): Endometrial Cancer-Patient Version

The NCI is the federal government's principal agency for cancer research and training. Here you can find more information about endometrial cancer treatment, research and coping with cancer.