Overview

Endometrial cancer is a type of cancer that begins as a growth of cells in the uterus. The uterus is the hollow, pear-shaped pelvic organ where fetal development happens.

Endometrial cancer begins in the layer of cells that form the lining of the uterus, called the endometrium. Endometrial cancer is sometimes called uterine cancer. Other types of cancer can form in the uterus, including uterine sarcoma, but they are much less common than endometrial cancer.

Endometrial cancer is often found at an early stage because it causes symptoms. Often the first symptom is irregular vaginal bleeding. If endometrial cancer is found early, surgically removing the uterus often cures it.

Symptoms

Symptoms of endometrial cancer may include:

  • Vaginal bleeding after menopause.
  • Bleeding between periods.
  • Pelvic pain.

When to see a doctor

Make an appointment with a health care professional if you experience any symptoms that worry you.

Causes

The cause of endometrial cancer isn't known. What's known is that something happens to cells in the lining of the uterus that changes them into cancer cells.

Endometrial cancer starts when cells in the lining of the uterus, called the endometrium, get changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. The changes tell the cells to multiply quickly. The changes also tell the cells to continue living when healthy cells would die as part of their natural life cycle. This causes a lot of extra cells. The cells might form a mass called a tumor. The cells can invade and destroy healthy body tissue. In time, the cells can break away and spread to other parts of the body.

Risk factors

Factors that increase the risk of endometrial cancer include:

  • Changes in the balance of hormones in the body. The two main hormones the ovaries make are estrogen and progesterone. Changes in the balance of these hormones cause changes in the endometrium.

    A disease or condition that increases the amount of estrogen, but not the level of progesterone, in the body can increase the risk of endometrial cancer. Examples include obesity, diabetes and irregular ovulation patterns, which might happen in polycystic ovary syndrome. Taking hormone therapy medicine that contains estrogen but not progestin after menopause increases the risk of endometrial cancer.

    A rare type of ovarian tumor that gives off estrogen also can increase the risk of endometrial cancer.

  • More years of menstruation. Starting menstruation before age 12 or beginning menopause later increases the risk of endometrial cancer. The more periods you've had, the more exposure your endometrium has had to estrogen.
  • Never having been pregnant. If you've never been pregnant, you have a higher risk of endometrial cancer than someone who has had at least one pregnancy.
  • Older age. As you get older, your risk of endometrial cancer increases. Endometrial cancer occurs most often after menopause.
  • Obesity. Being obese increases your risk of endometrial cancer. This may happen because extra body fat can alter your body's balance of hormones.
  • Hormone therapy for breast cancer. Taking the hormone therapy medicine tamoxifen for breast cancer can increase the risk of developing endometrial cancer. If you're taking tamoxifen, talk about the risk with your health care team. For most, the benefits of tamoxifen outweigh the small risk of endometrial cancer.
  • An inherited syndrome that increases the risk of cancer. Lynch syndrome increases the risk of colon cancer and other cancers, including endometrial cancer. Lynch syndrome is caused by a DNA change that's passed from parents to children. If a family member has been diagnosed with Lynch syndrome, ask your health care team about your risk of this genetic syndrome. If you've been diagnosed with Lynch syndrome, ask what cancer screenings you need.

Prevention

To reduce your risk of endometrial cancer, you may wish to:

  • Talk to your health care team about the risks of hormone therapy after menopause. If you're considering hormone replacement therapy to help control menopause symptoms, ask about the risks and benefits. Unless you've had your uterus removed, replacing estrogen alone after menopause may increase your risk of endometrial cancer. A hormone therapy medicine that combines estrogen and progestin can reduce this risk. Hormone therapy carries other risks, so weigh the benefits and risks with your health care team.
  • Consider taking birth control pills. Using oral contraceptives for at least one year may reduce endometrial cancer risk. Oral contraceptives are contraceptives that are taken in pill form. They also are called birth control pills. The risk reduction is thought to last for several years after you stop taking oral contraceptives. Oral contraceptives have side effects, though, so discuss the benefits and risks with your health care team.
  • Maintain a healthy weight. Obesity increases the risk of endometrial cancer, so work to achieve and maintain a healthy weight. If you need to lose weight, increase your physical activity and reduce the number of calories you eat each day.
By Mayo Clinic Staff