Endometrial cancer begins in the lining (endometrium) of the uterus.
Endometrial cancer is a type of cancer that begins in the uterus. The uterus is the hollow, pear-shaped pelvic organ where fetal development occurs.
Endometrial cancer begins in the layer of cells that form the lining (endometrium) of the uterus. 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 detected at an early stage because it frequently produces abnormal vaginal bleeding. If endometrial cancer is discovered early, removing the uterus surgically often cures endometrial cancer.
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Signs and symptoms of endometrial cancer may include:
- Vaginal bleeding after menopause
- Bleeding between periods
- Pelvic pain
When to see a doctor
Make an appointment with your doctor if you experience any persistent signs or symptoms that worry you.
Doctors don't know what causes endometrial cancer. What's known is that something occurs to create changes (mutations) in the DNA of cells in the endometrium — the lining of the uterus.
The mutation turns normal, healthy cells into abnormal cells. Healthy cells grow and multiply at a set rate, eventually dying at a set time. Abnormal cells grow and multiply out of control, and they don't die at a set time. The accumulating abnormal cells form a mass (tumor). Cancer cells invade nearby tissues and can separate from an initial tumor to spread elsewhere in the body (metastasize).
Female reproductive system
The ovaries, fallopian tubes, uterus, cervix and vagina (vaginal canal) make up the female reproductive system.
Factors that increase the risk of endometrial cancer include:
Changes in the balance of female hormones in the body. The ovaries make two main female hormones — estrogen and progesterone. Fluctuations 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 your body can increase your risk of endometrial cancer. Examples include irregular ovulation patterns, which might happen in polycystic ovary syndrome, obesity and diabetes. Taking hormones after menopause that contain estrogen but not progesterone increases the risk of endometrial cancer.
A rare type of ovarian tumor that secretes estrogen also can increase the risk of endometrial cancer.
- More years of menstruation. Starting menstruation at an early age — 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 occur because excess body fat alters your body's balance of hormones.
- Hormone therapy for breast cancer. Taking the hormone therapy drug tamoxifen for breast cancer can increase the risk of developing endometrial cancer. If you're taking tamoxifen, discuss this risk with your doctor. For most, the benefits of tamoxifen outweigh the small risk of endometrial cancer.
- An inherited colon cancer syndrome. Lynch syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC), is a syndrome that increases the risk of colon cancer and other cancers, including endometrial cancer. Lynch syndrome is caused by a gene mutation passed from parents to children. If a family member has been diagnosed with Lynch syndrome, discuss your risk of the genetic syndrome with your doctor. If you've been diagnosed with Lynch syndrome, ask your doctor what cancer screening tests you should undergo.
To reduce your risk of endometrial cancer, you may wish to:
- Talk to your doctor about the risks of hormone therapy after menopause. If you're considering hormone replacement therapy to help control menopause symptoms, talk to your doctor about the risks and benefits. Unless you've undergone a hysterectomy, replacing estrogen alone after menopause may increase your risk of endometrial cancer. Taking a combination of estrogen and progestin can reduce this risk. Hormone therapy carries other risks, so weigh the benefits and risks with your doctor.
- Consider taking birth control pills. Using oral contraceptives for at least one year may reduce endometrial cancer risk. 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 doctor.
- 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.
Endometrial cancer care at Mayo Clinic
May 20, 2021
- AskMayoExpert. Endometrial cancer. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2018.
- Niederhuber JE, et al., eds. Uterine cancer. In: Abeloff's Clinical Oncology. 6th ed. Philadelphia, Pa.: Elsevier; 2020. https://www.clinicalkey.com. Accessed May 24, 2019.
- Lobo RA, et al. Neoplastic diseases of the uterus. In: Comprehensive Gynecology. 7th ed. Philadelphia, Pa.: Elsevier; 2017. https://www.clinicalkey.com. Accessed May 24, 2019.
- American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins — Obstetrics. ACOG Practice Bulletin No. 149: Endometrial Cancer. Obstetrics & Gynecology. 2015;125:1006.
- Uterine neoplasms. Plymouth Meeting, Pa.: National Comprehensive Cancer Network. https://www.nccn.org/professionals/physician_gls/default.aspx. Accessed May 24, 2019.
- Palliative care. Plymouth Meeting, Pa.: National Comprehensive Cancer Network. https://www.nccn.org/professionals/physician_gls/default.aspx. Accessed May 24, 2019.
- Fader AN, et al. Utilization of minimally invasive surgery in endometrial cancer care. Obstetrics & Gynecology. 2016;127:91.
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